History log of /drivers/clk/clk.c
Revision Date Author Comments
3a3804ba0a4aa13d0479c6dd823c5c3a5dc5941f 19-Mar-2015 Badhri Jagan Sridharan <Badhri@google.com> clk: debugfs: Support frequency stats accounting

Added frequency statistics accounting to common
clk debug framework. This change tracks the
frequency of the clocks which don't have the
CLK_GET_RATE_NOCACHE flag set. This is done by
monitoring the calls to clk_set_rate, clk_enable
and then clk_disable.

There is a new node called frequency_stats_table
created under DEBUG_FS/clk/<clk_debug_name>/ to
report the collected statistics. In addition,
the stats also gets printed as a part of the
clk_summary. Frequency gets reported in HZ and
the time_spent gets reported in msec units.

sample output of clk_summary:

clock enable_cnt prepare_cnt rate accuracy phase
----------------------------------------------------------------------------------------
clk24mhz 2 3 24000000 0 0
*[ default_freq 48188]
* 400000000 54

default_freq accounts the time for which the
clk was on without an explicit call to the
clk_set_rate API. The [] braces highlight the
latest frequency set through clk_set_rate API.

Frequency accounting can be started(or)stopped
by writing 1(or)0 to /d/clk/freq_stats_on.
Writing 1 also causes the counters to reset.

Enabling CONFIG_FREQ_STATS_ACCOUNTING includes
the feature.

Enabling CONFIG_BEGIN_ACCOUNTING_FROM_BOOT
starts accounting right from boot.

Change-Id: I7333d6afd1494c9a7288c5da70877a734d3a64af
Signed-off-by: Badhri Jagan Sridharan <Badhri@google.com>
9824cf73c3a5e677bee6fcba43c4807e01ff1b4a 14-Jul-2014 Maxime Ripard <maxime.ripard@free-electrons.com> clk: Add a function to retrieve phase

The current phase API doesn't look into the actual hardware to get the phase
value, but will rather get it from a variable only set by the set_phase
function.

This will cause issue when the client driver will never call the set_phase
function, where we can end up having a reported phase that will not match what
the hardware has been programmed to by the bootloader or what phase is
programmed out of reset.

Add a new get_phase function for the drivers to implement so that we can get
this value.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Hans de Goede <hdegoede@redhat.com>
e59c5371fb9d8268d1c043172e88cecab9dc934f 19-Feb-2014 Mike Turquette <mturquette@linaro.org> clk: introduce clk_set_phase function & callback

A common operation for a clock signal generator is to shift the phase of
that signal. This patch introduces a new function to the clk.h API to
dynamically adjust the phase of a clock signal. Additionally this patch
introduces support for the new function in the common clock framework
via the .set_phase call back in struct clk_ops.

Signed-off-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Hans de Goede <hdegoede@redhat.com>
6314b6796e3c070d4c8086b08dfd453a0aeac4cf 05-Sep-2014 Stephen Boyd <sboyd@codeaurora.org> clk: Don't hold prepare_lock across debugfs creation

Rob Clark reports a lockdep splat that involves the prepare_lock
chained with the mmap semaphore.

======================================================
[ INFO: possible circular locking dependency detected ]
3.17.0-rc1-00050-g07a489b #802 Tainted: G W
-------------------------------------------------------
Xorg.bin/5413 is trying to acquire lock:
(prepare_lock){+.+.+.}, at: [<c0781280>] clk_prepare_lock+0x88/0xfc

but task is already holding lock:
(qcom_iommu_lock){+.+...}, at: [<c079f664>] qcom_iommu_unmap+0x1c/0x1f0

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #4 (qcom_iommu_lock){+.+...}:
[<c079f860>] qcom_iommu_map+0x28/0x450
[<c079eb50>] iommu_map+0xc8/0x12c
[<c056c1fc>] msm_iommu_map+0xb4/0x130
[<c05697bc>] msm_gem_get_iova_locked+0x9c/0xe8
[<c0569854>] msm_gem_get_iova+0x4c/0x64
[<c0562208>] mdp4_kms_init+0x4c4/0x6c0
[<c056881c>] msm_load+0x2ac/0x34c
[<c0545724>] drm_dev_register+0xac/0x108
[<c0547510>] drm_platform_init+0x50/0xf0
[<c0578a60>] try_to_bring_up_master.part.3+0xc8/0x108
[<c0578b48>] component_master_add_with_match+0xa8/0x104
[<c0568294>] msm_pdev_probe+0x64/0x70
[<c057e704>] platform_drv_probe+0x2c/0x60
[<c057cff8>] driver_probe_device+0x108/0x234
[<c057b65c>] bus_for_each_drv+0x64/0x98
[<c057cec0>] device_attach+0x78/0x8c
[<c057c590>] bus_probe_device+0x88/0xac
[<c057c9b8>] deferred_probe_work_func+0x68/0x9c
[<c0259db4>] process_one_work+0x1a0/0x40c
[<c025a710>] worker_thread+0x44/0x4d8
[<c025ec54>] kthread+0xd8/0xec
[<c020e9a8>] ret_from_fork+0x14/0x2c

-> #3 (&dev->struct_mutex){+.+.+.}:
[<c0541188>] drm_gem_mmap+0x38/0xd0
[<c05695b8>] msm_gem_mmap+0xc/0x5c
[<c02f0b6c>] mmap_region+0x35c/0x6c8
[<c02f11ec>] do_mmap_pgoff+0x314/0x398
[<c02de1e0>] vm_mmap_pgoff+0x84/0xb4
[<c02ef83c>] SyS_mmap_pgoff+0x94/0xbc
[<c020e8e0>] ret_fast_syscall+0x0/0x48

-> #2 (&mm->mmap_sem){++++++}:
[<c0321138>] filldir64+0x68/0x180
[<c0333fe0>] dcache_readdir+0x188/0x22c
[<c0320ed0>] iterate_dir+0x9c/0x11c
[<c03213b0>] SyS_getdents64+0x78/0xe8
[<c020e8e0>] ret_fast_syscall+0x0/0x48

-> #1 (&sb->s_type->i_mutex_key#3){+.+.+.}:
[<c03fc544>] __create_file+0x58/0x1dc
[<c03fc70c>] debugfs_create_dir+0x1c/0x24
[<c0781c7c>] clk_debug_create_subtree+0x20/0x170
[<c0be2af8>] clk_debug_init+0xec/0x14c
[<c0208c70>] do_one_initcall+0x8c/0x1c8
[<c0b9cce4>] kernel_init_freeable+0x13c/0x1dc
[<c0877bc4>] kernel_init+0x8/0xe8
[<c020e9a8>] ret_from_fork+0x14/0x2c

-> #0 (prepare_lock){+.+.+.}:
[<c087c408>] mutex_lock_nested+0x70/0x3e8
[<c0781280>] clk_prepare_lock+0x88/0xfc
[<c0782c50>] clk_prepare+0xc/0x24
[<c079f474>] __enable_clocks.isra.4+0x18/0xa4
[<c079f614>] __flush_iotlb_va+0xe0/0x114
[<c079f6f4>] qcom_iommu_unmap+0xac/0x1f0
[<c079ea3c>] iommu_unmap+0x9c/0xe8
[<c056c2fc>] msm_iommu_unmap+0x64/0x84
[<c0569da4>] msm_gem_free_object+0x11c/0x338
[<c05413ec>] drm_gem_object_handle_unreference_unlocked+0xfc/0x130
[<c0541604>] drm_gem_object_release_handle+0x50/0x68
[<c0447a98>] idr_for_each+0xa8/0xdc
[<c0541c10>] drm_gem_release+0x1c/0x28
[<c0540b3c>] drm_release+0x370/0x428
[<c031105c>] __fput+0x98/0x1e8
[<c025d73c>] task_work_run+0xb0/0xfc
[<c02477ec>] do_exit+0x2ec/0x948
[<c0247ec0>] do_group_exit+0x4c/0xb8
[<c025180c>] get_signal+0x28c/0x6ac
[<c0211204>] do_signal+0xc4/0x3e4
[<c02116cc>] do_work_pending+0xb4/0xc4
[<c020e938>] work_pending+0xc/0x20

other info that might help us debug this:

Chain exists of:
prepare_lock --> &dev->struct_mutex --> qcom_iommu_lock

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(qcom_iommu_lock);
lock(&dev->struct_mutex);
lock(qcom_iommu_lock);
lock(prepare_lock);

*** DEADLOCK ***

3 locks held by Xorg.bin/5413:
#0: (drm_global_mutex){+.+.+.}, at: [<c0540800>] drm_release+0x34/0x428
#1: (&dev->struct_mutex){+.+.+.}, at: [<c05413bc>] drm_gem_object_handle_unreference_unlocked+0xcc/0x130
#2: (qcom_iommu_lock){+.+...}, at: [<c079f664>] qcom_iommu_unmap+0x1c/0x1f0

stack backtrace:
CPU: 1 PID: 5413 Comm: Xorg.bin Tainted: G W 3.17.0-rc1-00050-g07a489b #802
[<c0216290>] (unwind_backtrace) from [<c0211d8c>] (show_stack+0x10/0x14)
[<c0211d8c>] (show_stack) from [<c087a078>] (dump_stack+0x98/0xb8)
[<c087a078>] (dump_stack) from [<c027f024>] (print_circular_bug+0x218/0x340)
[<c027f024>] (print_circular_bug) from [<c0283e08>] (__lock_acquire+0x1d24/0x20b8)
[<c0283e08>] (__lock_acquire) from [<c0284774>] (lock_acquire+0x9c/0xbc)
[<c0284774>] (lock_acquire) from [<c087c408>] (mutex_lock_nested+0x70/0x3e8)
[<c087c408>] (mutex_lock_nested) from [<c0781280>] (clk_prepare_lock+0x88/0xfc)
[<c0781280>] (clk_prepare_lock) from [<c0782c50>] (clk_prepare+0xc/0x24)
[<c0782c50>] (clk_prepare) from [<c079f474>] (__enable_clocks.isra.4+0x18/0xa4)
[<c079f474>] (__enable_clocks.isra.4) from [<c079f614>] (__flush_iotlb_va+0xe0/0x114)
[<c079f614>] (__flush_iotlb_va) from [<c079f6f4>] (qcom_iommu_unmap+0xac/0x1f0)
[<c079f6f4>] (qcom_iommu_unmap) from [<c079ea3c>] (iommu_unmap+0x9c/0xe8)
[<c079ea3c>] (iommu_unmap) from [<c056c2fc>] (msm_iommu_unmap+0x64/0x84)
[<c056c2fc>] (msm_iommu_unmap) from [<c0569da4>] (msm_gem_free_object+0x11c/0x338)
[<c0569da4>] (msm_gem_free_object) from [<c05413ec>] (drm_gem_object_handle_unreference_unlocked+0xfc/0x130)
[<c05413ec>] (drm_gem_object_handle_unreference_unlocked) from [<c0541604>] (drm_gem_object_release_handle+0x50/0x68)
[<c0541604>] (drm_gem_object_release_handle) from [<c0447a98>] (idr_for_each+0xa8/0xdc)
[<c0447a98>] (idr_for_each) from [<c0541c10>] (drm_gem_release+0x1c/0x28)
[<c0541c10>] (drm_gem_release) from [<c0540b3c>] (drm_release+0x370/0x428)
[<c0540b3c>] (drm_release) from [<c031105c>] (__fput+0x98/0x1e8)
[<c031105c>] (__fput) from [<c025d73c>] (task_work_run+0xb0/0xfc)
[<c025d73c>] (task_work_run) from [<c02477ec>] (do_exit+0x2ec/0x948)
[<c02477ec>] (do_exit) from [<c0247ec0>] (do_group_exit+0x4c/0xb8)
[<c0247ec0>] (do_group_exit) from [<c025180c>] (get_signal+0x28c/0x6ac)
[<c025180c>] (get_signal) from [<c0211204>] (do_signal+0xc4/0x3e4)
[<c0211204>] (do_signal) from [<c02116cc>] (do_work_pending+0xb4/0xc4)
[<c02116cc>] (do_work_pending) from [<c020e938>] (work_pending+0xc/0x20)

We can break this chain if we don't hold the prepare_lock while
creating debugfs directories. We only hold the prepare_lock right
now because we're traversing the clock tree recursively and we
don't want the hierarchy to change during the traversal.
Replacing this traversal with a simple linked list walk allows us
to only grab a list lock instead of the prepare_lock, thus
breaking the lock chain.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
067bb1741c27c8d3b74ac98c0b8fc12b31e67005 21-Aug-2014 Tero Kristo <t-kristo@ti.com> clk: prevent erronous parsing of children during rate change

In some cases, clocks can switch their parent with clk_set_rate, for
example clk_mux can do this in some cases. Current implementation of
clk_change_rate uses un-safe list iteration on the clock children, which
will cause wrong clocks to be parsed in case any of the clock children
change their parents during the change rate operation. Fixed by using
the safe list iterator instead.

The problem was detected due to some divide by zero errors generated
by clock init on dra7-evm board, see discussion under
http://article.gmane.org/gmane.linux.ports.arm.kernel/349180 for details.

Fixes: 71472c0c06cf ("clk: add support for clock reparent on set_rate")
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Reported-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
abeab450bfe823079c8a3abf5123f41a0da62392 03-Jul-2014 Chris Brand <chris.brand@linaro.org> clk: Propagate any error return from debug_init()

If the .debug_init op is provided, it will be called by
clk_debug_create_one(). If debug_init() returns an error code,
clk_debug_create_one() will return -ENOMEM, regardless of the
value returned from debug_init(). Tweak the code to return
the actual value returned by debug_init() instead.

Signed-off-by: Chris Brand <chris.brand@linaro.org>
Reviewed-by: Matt Porter <mporter@linaro.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
86be408bfbd846fab3c4ac21d6f9298bd2e4b790 18-Jun-2014 Sylwester Nawrocki <s.nawrocki@samsung.com> clk: Support for clock parents and rates assigned from device tree

This patch adds helper functions to configure clock parents and rates
as specified through 'assigned-clock-parents', 'assigned-clock-rates'
DT properties for a clock provider or clock consumer device.
The helpers are now being called by the bus code for the platform, I2C
and SPI busses, before the driver probing and also in the clock core
after registration of a clock provider.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
fb2b3c9f68574738c70b9df5fc2bea40f91dd8be 26-Jun-2014 Peter De Schrijver <pdeschrijver@nvidia.com> clk: define and export clk_debugs_add_file

Define and export a new function clk_debugs_add_file which adds a file
to a existing clock's debugfs directory. This can be used by clock
providers to add debugfs entries which are not related to a specific clock
type. Examples include the ability to measure the rate of a clock. It can
also be used by modules to create new debugfs entries. This is useful if you
want to expose features for testing which can potentially cause system
instability such as allowing to change a clock's rate from userspace.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
6b44c854b0f75d8dd1ea7f1d37621cfd82fbd2a9 01-Jul-2014 Sachin Kamat <sachin.kamat@samsung.com> clk: Fix build warnings

‘all_lists’ and ‘orphan_list’ is accessed only when DEBUG_FS is defined.
Thus, make their compilation conditional to fix the below warnings introduced
by commit 27b8d5f723 ("clk: flatten clk tree in debugfs"):
drivers/clk/clk.c:40:27: warning: ‘all_lists’ defined but not used [-Wunused-variable]
drivers/clk/clk.c:46:27: warning: ‘orphan_list’ defined but not used [-Wunused-variable]

Signed-off-by: Sachin Kamat <sachin.kamat@samsung.com>
Cc: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
27b8d5f723e64b5f7beac45a4d5785906d0a2f9d 30-May-2014 Peter De Schrijver <pdeschrijver@nvidia.com> clk: flatten clk tree in debugfs

This patch flattens the clk tree in CCF debugfs. Instead of representing the
clocks and their hierarchy as a directory structure under
/sys/kernel/debug/clk, each clock gets a single directory directly under
/sys/kernel/debug/clk. The orphans directory is replaced by a file called
clk_orphan_summary.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
1cdf8ee2f88bbc14c697a0b8a2f25f58ed57d591 03-Jun-2014 Arnd Bergmann <arnd@arndb.de> clk: export __clk_round_rate for providers

Commit 99cbd064b0 ("clk: qcom: Support display RCG clocks") adds
a use of the __clk_round_rate in a clock provided that can be built
as a loadable module.

This exports the symbol to avoid the build error from compiling
the qcom clock as a module.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
fb8abb7aefe8454e3b478ef11da78ea25b891ad4 25-Mar-2014 Geert Uytterhoeven <geert+renesas@glider.be> clk: Neaten clk_summary output

- Limit ruler to 80 characters (was: 81),
- Widen rate column by 1 for nicer spacing,
- Right-align numbers and their column headers,
- Move a newline to reduce the number of seq_printf() calls,
- Use set_puts() for fixed strings.

Before:

clock enable_cnt prepare_cnt rate accuracy
---------------------------------------------------------------------------------
extal 2 2 20000000 0
thermal 1 1 20000000 0
cp 0 0 10000000 0
tpu0 0 0 10000000 0
tmu0 0 0 10000000 0
main 1 1 20000000 0
pll3 0 0 1600000000 0
ddr 0 0 200000000 0
zb3d2 0 0 200000000 0
zb3 0 0 400000000 0
pll1 4 4 1560000000 0
oscclk 0 0 126953 0
rclk 1 1 31738 0
cmt1 0 0 31738 0
cmt0 1 1 31738 0
imp 0 0 390000000 0

After:

clock enable_cnt prepare_cnt rate accuracy
--------------------------------------------------------------------------------
extal 2 2 20000000 0
thermal 1 1 20000000 0
cp 0 0 10000000 0
tpu0 0 0 10000000 0
tmu0 0 0 10000000 0
main 1 1 20000000 0
pll3 0 0 1600000000 0
ddr 0 0 200000000 0
zb3d2 0 0 200000000 0
zb3 0 0 400000000 0
pll1 4 4 1560000000 0
oscclk 0 0 126953 0
rclk 1 1 31738 0
cmt1 0 0 31738 0
cmt0 1 1 31738 0
imp 0 0 390000000 0

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
63589e92c2d975cc63222e5bd4a9a1fa2a1187ac 27-Mar-2014 Stephen Boyd <sboyd@codeaurora.org> clk: Ignore error and NULL pointers passed to clk_{unprepare, disable}()

This simplifies error paths in drivers that use optional clocks
by allowing the NULL or error pointer to be passed
unconditionally.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
8f2c2db132cf5f4ffb4b9702ddb7e6bc5a343814 27-Mar-2014 Stephen Boyd <sboyd@codeaurora.org> clk: Consolidate recalc rate logic

The same if-else statement exists four times to recalculate the
rate of a clock. Consolidate this logic into a single function to
save some lines.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
86a612349fa58467cd63b30748114ec377d61807 27-Mar-2014 Stephen Boyd <sboyd@codeaurora.org> clk: Don't check for missing ops in clk_set_parent()

We dereference clk->ops during clock registration so this check
for NULL ops can't possibly ever be true.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
874f224cc52d64c912087e68e3724be95ad80ee7 19-Apr-2014 Stephen Boyd <sboyd@codeaurora.org> clk: Fix slab corruption in clk_unregister()

When a clock is unregsitered, we iterate over the list of
children and reparent them to NULL (i.e. orphan list). While
iterating the list, we should use the safe iterators because the
children list for this clock is changing when we reparent the
children to NULL. Failure to iterate safely can lead to slab
corruption like this:

=============================================================================
BUG kmalloc-128 (Not tainted): Poison overwritten
-----------------------------------------------------------------------------

Disabling lock debugging due to kernel taint
INFO: 0xed0c4900-0xed0c4903. First byte 0x0 instead of 0x6b
INFO: Allocated in clk_register+0x20/0x1bc age=297 cpu=2 pid=70
__slab_alloc.isra.39.constprop.42+0x410/0x454
kmem_cache_alloc_trace+0x200/0x24c
clk_register+0x20/0x1bc
devm_clk_register+0x34/0x68
0xbf0000f0
platform_drv_probe+0x18/0x48
driver_probe_device+0x94/0x360
__driver_attach+0x94/0x98
bus_for_each_dev+0x54/0x88
bus_add_driver+0xe8/0x204
driver_register+0x78/0xf4
do_one_initcall+0xc4/0x17c
load_module+0x19ac/0x2294
SyS_init_module+0xa4/0x110
ret_fast_syscall+0x0/0x48
INFO: Freed in clk_unregister+0xd4/0x140 age=23 cpu=2 pid=73
__slab_free+0x38/0x41c
clk_unregister+0xd4/0x140
release_nodes+0x164/0x1d8
__device_release_driver+0x60/0xb0
driver_detach+0xb4/0xb8
bus_remove_driver+0x5c/0xc4
SyS_delete_module+0x148/0x1d8
ret_fast_syscall+0x0/0x48
INFO: Slab 0xeec50b90 objects=25 used=0 fp=0xed0c5400 flags=0x4080
INFO: Object 0xed0c48c0 @offset=2240 fp=0xed0c4a00

Bytes b4 ed0c48b0: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ
Object ed0c48c0: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
Object ed0c48d0: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
Object ed0c48e0: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
Object ed0c48f0: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
Object ed0c4900: 00 00 00 00 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b ....kkkkkkkkkkkk
Object ed0c4910: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
Object ed0c4920: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
Object ed0c4930: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5 kkkkkkkkkkkkkkk.
Redzone ed0c4940: bb bb bb bb ....
Padding ed0c49e8: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ
Padding ed0c49f8: 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ
CPU: 3 PID: 75 Comm: mdev Tainted: G B 3.14.0-11033-g2054ba5ca781 #35
[<c0014be0>] (unwind_backtrace) from [<c0012240>] (show_stack+0x10/0x14)
[<c0012240>] (show_stack) from [<c04b74a0>] (dump_stack+0x70/0xbc)
[<c04b74a0>] (dump_stack) from [<c00f7a78>] (check_bytes_and_report+0xbc/0x100)
[<c00f7a78>] (check_bytes_and_report) from [<c00f7c48>] (check_object+0x18c/0x218)
[<c00f7c48>] (check_object) from [<c00f7efc>] (__free_slab+0x104/0x144)
[<c00f7efc>] (__free_slab) from [<c04b6668>] (__slab_free+0x3dc/0x41c)
[<c04b6668>] (__slab_free) from [<c014c008>] (load_elf_binary+0x88/0x12b4)
[<c014c008>] (load_elf_binary) from [<c0105a44>] (search_binary_handler+0x78/0x18c)
[<c0105a44>] (search_binary_handler) from [<c0106fc0>] (do_execve+0x490/0x5dc)
[<c0106fc0>] (do_execve) from [<c0036b8c>] (____call_usermodehelper+0x134/0x168)
[<c0036b8c>] (____call_usermodehelper) from [<c000f048>] (ret_from_fork+0x14/0x2c)
FIX kmalloc-128: Restoring 0xed0c4900-0xed0c4903=0x6b

Fixes: fcb0ee6a3d33 (clk: Implement clk_unregister)
Cc: Jiada Wang <jiada_wang@mentor.com>
Cc: Sylwester Nawrocki <s.nawrocki@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Cc: stable@vger.kernel.org
293ba3b4a4fd54891b900f2911d1a57e1ed4a843 19-Apr-2014 Stephen Boyd <sboyd@codeaurora.org> clk: Fix double free due to devm_clk_register()

Now that clk_unregister() frees the struct clk we're
unregistering we'll free memory twice: first we'll call kfree()
in __clk_release() with an address kmalloc doesn't know about and
second we'll call kfree() in the devres layer. Remove the
allocation of struct clk in devm_clk_register() and let
clk_release() handle it. This fixes slab errors like:

=============================================================================
BUG kmalloc-128 (Not tainted): Invalid object pointer 0xed08e8d0
-----------------------------------------------------------------------------

Disabling lock debugging due to kernel taint
INFO: Slab 0xeec503f8 objects=25 used=15 fp=0xed08ea00 flags=0x4081
CPU: 2 PID: 73 Comm: rmmod Tainted: G B 3.14.0-11032-g526e9c764381 #34
[<c0014be0>] (unwind_backtrace) from [<c0012240>] (show_stack+0x10/0x14)
[<c0012240>] (show_stack) from [<c04b74dc>] (dump_stack+0x70/0xbc)
[<c04b74dc>] (dump_stack) from [<c00f6778>] (slab_err+0x74/0x84)
[<c00f6778>] (slab_err) from [<c04b6278>] (free_debug_processing+0x2cc/0x31c)
[<c04b6278>] (free_debug_processing) from [<c04b6300>] (__slab_free+0x38/0x41c)
[<c04b6300>] (__slab_free) from [<c03931bc>] (clk_unregister+0xd4/0x140)
[<c03931bc>] (clk_unregister) from [<c02fb774>] (release_nodes+0x164/0x1d8)
[<c02fb774>] (release_nodes) from [<c02f8698>] (__device_release_driver+0x60/0xb0)
[<c02f8698>] (__device_release_driver) from [<c02f9080>] (driver_detach+0xb4/0xb8)
[<c02f9080>] (driver_detach) from [<c02f8480>] (bus_remove_driver+0x5c/0xc4)
[<c02f8480>] (bus_remove_driver) from [<c008c9b8>] (SyS_delete_module+0x148/0x1d8)
[<c008c9b8>] (SyS_delete_module) from [<c000ef80>] (ret_fast_syscall+0x0/0x48)
FIX kmalloc-128: Object at 0xed08e8d0 not freed

Fixes: fcb0ee6a3d33 (clk: Implement clk_unregister)
Cc: Jiada Wang <jiada_wang@mentor.com>
Cc: Sylwester Nawrocki <s.nawrocki@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Cc: stable@vger.kernel.org
e5ca8fb4cca90706e115f65097a775795415eca5 27-Mar-2014 Sylwester Nawrocki <s.nawrocki@samsung.com> clk: Fix minor errors in of_clk_init() function comments

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
3f6d439f202243a1594f2e1b86620af0d342bbe6 27-Mar-2014 Sylwester Nawrocki <s.nawrocki@samsung.com> clk: reverse default clk provider initialization order in of_clk_init()

This restores the default clocks registration order as parsed from
devicetree, i.e. as before commit 1771b10d605d26ccee771a7fb4b08718
"clk: respect the clock dependencies in of_clk_init", for when there
is no explicit parent clock dependencies between clock providers
specified in the device tree.

It prevents regressions (boot failure, division by 0 errors) on
imx and exynos platforms.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Tested-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
c646cbf10fb3347ecda290dfce96b813a423ca07 21-Mar-2014 Alex Elder <elder@linaro.org> clk: support hardware-specific debugfs entries

Add a new clk_ops->debug_init method to allow a clock hardware
driver to populate the clock's debugfs directory with entries
beyond those common for every clock.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
f736386160f7d7419499f877b5abb1412ab4aa32 16-Jan-2014 Sascha Hauer <s.hauer@pengutronix.de> clk: turn rate change failed warning into pr_debug

If a rate change failed it's the opportunity of the caller to handle
this. Do not spam the log with a message.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Mike Turquette <mturquette@linaro.org>
1771b10d605d26ccee771a7fb4b08718c124097a 24-Feb-2014 Gregory CLEMENT <gregory.clement@free-electrons.com> clk: respect the clock dependencies in of_clk_init

Until now the clock providers were initialized in the order found in
the device tree. This led to have the dependencies between the clocks
not respected: children clocks could be initialized before their
parent clocks.

Instead of forcing each platform to manage its own initialization order,
this patch adds this work inside the framework itself.

Using the data of the device tree the of_clk_init function now delayed
the initialization of a clock provider if its parent provider was not
ready yet.

The strict dependency check (all parents of a given clk must be
initialized) was added by Boris BREZILLON

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
00efcb1c8e1c3c5e5d3ce6f0682d66402911a84f 07-Jan-2014 Sylwester Nawrocki <s.nawrocki@samsung.com> clk: Correct handling of NULL clk in __clk_{get, put}

Ensure clk->kref is dereferenced only when clk is not NULL.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Tested-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
a34cd4666f3da84228a82f70c94b8d9b692034ea 25-Nov-2013 Jean-Francois Moine <moinejf@free.fr> clk: return probe defer when DT clock not yet ready

At probe time, a clock device may not be ready when some other device
wants to use it.

This patch lets the functions clk_get/devm_clk_get return a probe defer
when the clock is defined in the DT but not yet available.

Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Tested-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
86bcfa2e87c42b8af77188e7a939e952199d4da1 25-Feb-2014 Mike Turquette <mturquette@linaro.org> clk: add pr_debug & kerneldoc around clk notifiers

Both the pr_err and the additional kerneldoc aim to help when debugging
errors thrown from within a clock rate-change notifier callback.

Reported-by: Sören Brinkmann <soren.brinkmann@xilinx.com>
Acked-by: Sören Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
7a0fc1a3df82d29e00b4c9f88a6b37450d6711f1 13-Feb-2014 Ben Dooks <ben.dooks@codethink.co.uk> clk: add clock-indices support

Add a property called clock-indices to allow clock-output-names
to be used where the index used to lookup a clock is not a 1:1
mapping to the array position in the clock-output-names

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
5324fda79e28d1d4db0631369b39ff263d0142b4 22-Jan-2014 Soren Brinkmann <soren.brinkmann@xilinx.com> clk: Fix notifier documentation

Contradicting to documenation, the notifier callbacks do receive
the original clock rate in struct clk_notifier_data.old_rate and the new
frequency struct clk_notifier_data.new_rate, independent of the
notification reason.

This behavior also seems to make more sense, since callbacks can use the
same code to deterimine whether clocks are scaled up or down. Something
which would not even possible in the post-rate-change case if the
behavior was as documented.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
0b7f04b868ec1230cf2dd698697dbc32a509ea4d 18-Jan-2014 Stephen Boyd <sboyd@codeaurora.org> clk: Export more clk-provider functions

Allow drivers to be compiled as modules by exporting more clock
provider functions.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
819b4861c18d602463cfe815041d11fd81002654 22-Oct-2013 Tero Kristo <t-kristo@ti.com> CLK: ti: add init support for clock IP blocks

ti_dt_clk_init_provider() can now be used to initialize the contents of
a single clock IP block. This parses all the clocks under the IP block
and calls the corresponding init function for them.

This patch also introduces a helper function for the TI clock drivers
to get register info from DT and append the master IP info to this.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
3fa2252b7a78a8057017471a28f47b306e95ee26 15-Jan-2014 Stephen Boyd <sboyd@codeaurora.org> clk: Add set_rate_and_parent() op

Some of Qualcomm's clocks can change their parent and rate at the
same time with a single register write. Add support for this
hardware to the common clock framework by adding a new
set_rate_and_parent() op. When the clock framework determines
that both the parent and the rate are going to change during
clk_set_rate() it will call the .set_rate_and_parent() op if
available and fall back to calling .set_parent() followed by
.set_rate() otherwise.

Reviewed-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
ea72dc2cf9552631e43327ce593bdbb0b9fdf058 19-Dec-2013 Mike Turquette <mturquette@linaro.org> clk: remove CONFIG_COMMON_CLK_DEBUG

Populate ${DEBUGS_MOUNT_POINT}/clk if CONFIG_DEBUG_FS is set. This
eliminates the extra (annoying) step of enabling the config option
manually.

Signed-off-by: Mike Turquette <mturquette@linaro.org>
5279fc402ae59361a224d641d5823b21b4206232 21-Dec-2013 Boris BREZILLON <b.brezillon@overkiz.com> clk: add clk accuracy retrieval support

The clock accuracy is expressed in ppb (parts per billion) and represents
the possible clock drift.
Say you have a clock (e.g. an oscillator) which provides a fixed clock of
20MHz with an accuracy of +- 20Hz. This accuracy expressed in ppb is
20Hz/20MHz = 1000 ppb (or 1 ppm).

Clock users may need the clock accuracy information in order to choose
the best clock (the one with the best accuracy) across several available
clocks.

This patch adds clk accuracy retrieval support for common clk framework by
means of a new function called clk_get_accuracy.
This function returns the given clock accuracy expressed in ppb.

In order to get the clock accuracy, this implementation adds one callback
called recalc_accuracy to the clk_ops structure.
This callback is given the parent clock accuracy (if the clock is not a
root clock) and should recalculate the given clock accuracy.

This callback is optional and may be implemented if the clock is not
a perfect clock (accuracy != 0 ppb).

Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
3a5aec246f294004564cbe960724fa0ace59a4c5 16-Oct-2013 Stephen Boyd <sboyd@codeaurora.org> clk: Fix debugfs reparenting NULL pointer dereference

Adding clocks from a kernel module can cause a NULL pointer
dereference if the parent of a clock is added after the clock is
added. This happens because __clk_init() iterates over the list
of orphans and reparents the orphans to the clock being
registered before creating the debugfs entry for the clock.
Create the debugfs entry first before reparenting the orphans.

Unable to handle kernel NULL pointer dereference at virtual address 00000028
pgd = ef3e4000
[00000028] *pgd=bf810831
Internal error: Oops: 17 [#1] PREEMPT SMP ARM
Modules linked in: mmcc_8960(+)
CPU: 0 PID: 52 Comm: modprobe Not tainted 3.12.0-rc2-00023-g1021a28-dirty #659
task: ef319200 ti: ef3a6000 task.ti: ef3a6000
PC is at lock_rename+0x24/0xc4
LR is at debugfs_rename+0x34/0x208
pc : [<c0317238>] lr : [<c047dfe4>] psr: 00000013
sp : ef3a7b88 ip : ef3a7ba8 fp : ef3a7ba4
r10: ef3d51cc r9 : ef3bc680 r8 : ef3d5210
r7 : ef3bc640 r6 : eee287e0 r5 : eee287e0 r4 : 00000000
r3 : ef3bc640 r2 : 00000000 r1 : eee287e0 r0 : 00000000
Flags: nzcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
Control: 10c5787d Table: af3e406a DAC: 00000015
Process modprobe (pid: 52, stack limit = 0xef3a6240)
Stack: (0xef3a7b88 to 0xef3a8000)
7b80: ef3bc640 ee4047e0 00000000 eee287e0 ef3a7bec ef3a7ba8
7ba0: c047dfe4 c0317220 ef3bc680 ef3d51cc ef3a7bdc ef3a7bc0 c06e29d0 c0268784
7bc0: c08946e8 ef3d5210 00000000 ef3bc700 ef3d5290 ef3d5210 ef3bc680 ef3d51cc
7be0: ef3a7c0c ef3a7bf0 c05b9e9c c047dfbc 00000000 00000000 ef3d5210 ef3d5290
7c00: ef3a7c24 ef3a7c10 c05baebc c05b9e30 00000001 00000001 ef3a7c64 ef3a7c28
7c20: c05bb124 c05bae9c bf000cd8 ef3bc7c0 000000d0 c0ff129c bf001774 00000002
7c40: ef3bc740 ef3d5290 ef0f9a10 bf001774 bf00042c 00000061 ef3a7c8c ef3a7c68
7c60: c05bb480 c05baed8 bf001774 ef3d5290 ef0f9a10 bf001774 ef38bc10 ef0f9a00
7c80: ef3a7cac ef3a7c90 c05bb5a8 c05bb3a0 bf001774 00000062 ef0f9a10 ef38bc18
7ca0: ef3a7cec ef3a7cb0 bf00010c c05bb56c 00000000 ef38ba00 00000000 ef3d60d0
7cc0: ef3a7cdc c0fefc24 ef0f9a10 c0a091c0 bf000d24 00000000 bf0029f0 bf006000
7ce0: ef3a7cfc ef3a7cf0 c05156c0 bf000040 ef3a7d2c ef3a7d00 c0513f5c c05156a8
7d00: ef3a7d2c ef0f9a10 ef0f9a10 bf000d24 ef0f9a44 c09ca588 00000000 bf006000
7d20: ef3a7d4c ef3a7d30 c05142b8 c0513ecc ef0fd25c 00000000 bf000d24 c0514214
7d40: ef3a7d74 ef3a7d50 c0512030 c0514220 ef0050a8 ef0fd250 ef0050f8 bf000d24
7d60: ef37c100 c09ed150 ef3a7d84 ef3a7d78 c05139c8 c0511fd8 ef3a7
7d80: c051344c c05139a8 bf000864 c09ca588 ef3a7db4 bf000d24 bf002
7da0: c09ca588 00000000 ef3a7dcc ef3a7db8 c05149dc c0513360 ef3a7
7dc0: ef3a7ddc ef3a7dd0 c0515914 c0514960 ef3a7dec ef3a7de0 bf006
7de0: ef3a7e74 ef3a7df0 c0208800 bf00600c ef3a7e1c ef3a7e00 c04c5
7e00: ffffffff c09d46c4 00000000 bf0029a8 ef3a7e34 ef3a7e20 c024c
7e20: ffffffff c09d46c4 ef3a7e5c ef3a7e38 c024e2fc c024ce40 00000
7e40: ef3a7f48 bf0029b4 bf0029a8 271aeb1c ef3a7f48 bf0029a8 00000001 ef383c00
7e60: bf0029f0 00000001 ef3a7f3c ef3a7e78 c028fac4 c0208718 bf0029b4 00007fff
7e80: c028cd58 000000d2 f0065000 00000000 ef3a7ebc 00000000 00000000 bf0029b4
7ea0: 00000000 bf0029ac bf0029b4 ef3a6000 ef3a7efc c08bf128 00000000 00000000
7ec0: 00000000 00000000 00000000 00000000 6e72656b 00006c65 00000000 00000000
7ee0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
7f00: 00000000 00000000 00000000 271aeb1c ef3a7f2c 00016376 b6f38008 001d3774
7f20: 00000080 c020f968 ef3a6000 00000000 ef3a7fa4 ef3a7f40 c02904dc c028e178
7f40: c020f898 010ccfa8 f0065000 00016376 f0073f60 f0073d7d f007a1e8 00002b24
7f60: 000039e4 00000000 00000000 00000000 0000002f 00000030 00000019 00000016
7f80: 00000012 00000000 00000000 010de1b2 b6f38008 010ccfa8 00000000 ef3a7fa8
7fa0: c020f6c0 c0290434 010de1b2 b6f38008 b6f38008 00016376 001d3774 00000000
7fc0: 010de1b2 b6f38008 010ccfa8 00000080 010de1b2 bedb6f90 010de1c9 0001d8dc
7fe0: 0000000c bedb674c 0001ce30 000094c4 60000010 b6f38008 00000008 0000001d
[<c0317238>] (lock_rename+0x24/0xc4) from [<c047dfe4>] (debugfs_rename+0x34/0x208)
[<c047dfe4>] (debugfs_rename+0x34/0x208) from [<c05b9e9c>] (clk_debug_reparent+0x78/0xc0)
[<c05baebc>] (__clk_reparent+0x2c/0x3c) from [<c05bb124>] (__clk_init+0x258/0x4c8)
[<c05bb124>] (__clk_init+0x258/0x4c8) from [<c05bb480>] (_clk_register+0xec/0x1cc)
[<c05bb480>] (_clk_register+0xec/0x1cc) from [<c05bb5a8>] (devm_clk_register+0x48/0x7c)
[<c05bb5a8>] (devm_clk_register+0x48/0x7c) from [<bf00010c>] (msm_mmcc_8960_probe+0xd8/0x190 [mmcc_8960])
[<bf00010c>] (msm_mmcc_8960_probe+0xd8/0x190 [mmcc_8960]) from [<c05156c0>] (platform_drv_probe+0x24/0x28)
[<c05156c0>] (platform_drv_probe+0x24/0x28) from [<c0513f5c>] (driver_probe_device+0x9c/0x354)
[<c0513f5c>] (driver_probe_device+0x9c/0x354) from [<c05142b8>] (__driver_attach+0xa4/0xa8)
[<c05142b8>] (__driver_attach+0xa4/0xa8) from [<c0512030>] (bus_for_each_dev+0x64/0x98)
[<c0512030>] (bus_for_each_dev+0x64/0x98) from [<c05139c8>] (driver_attach+0x2c/0x30)
[<c05139c8>] (driver_attach+0x2c/0x30) from [<c051344c>] (bus_add_driver+0xf8/0x2a8)
[<c051344c>] (bus_add_driver+0xf8/0x2a8) from [<c05149dc>] (driver_register+0x88/0x104)
[<c05149dc>] (driver_register+0x88/0x104) from [<c0515914>] (__platform_driver_register+0x58/0x6c)
[<c0515914>] (__platform_driver_register+0x58/0x6c) from [<bf006018>] (msm_mmcc_8960_driver_init+0x18/0x24 [mmcc_8960])
[<bf006018>] (msm_mmcc_8960_driver_init+0x18/0x24 [mmcc_8960]) from [<c0208800>] (do_one_initcall+0xf4/0x1b8)
[<c0208800>] (do_one_initcall+0xf4/0x1b8) from [<c028fac4>] (load_module+0x1958/0x22bc)
[<c028fac4>] (load_module+0x1958/0x22bc) from [<c02904dc>] (SyS_init_module+0xb4/0x120)
[<c02904dc>] (SyS_init_module+0xb4/0x120) from [<c020f6c0>] (ret_fast_syscall+0x0/0x48)
Code: e1500001 e1a04000 e1a05001 0a000021 (e5903028)

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
fcb0ee6a3d331fb23dbb546500021f6e4cac5689 24-Aug-2013 Sylwester Nawrocki <s.nawrocki@samsung.com> clk: Implement clk_unregister

clk_unregister() is currently not implemented and it is required when
a clock provider module needs to be unloaded.

Normally the clock supplier module is prevented to be unloaded by
taking reference on the module in clk_get().

For cases when the clock supplier module deinitializes despite the
consumers of its clocks holding a reference on the module, e.g. when
the driver is unbound through "unbind" sysfs attribute, there are
empty clock ops added. These ops are assigned temporarily to struct
clk and used until all consumers release the clock, to avoid invoking
callbacks from the module which just got removed.

Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
ac2df527fb407b61f9c812a99035b62a75a77d6d 24-Aug-2013 Sylwester Nawrocki <s.nawrocki@samsung.com> clk: Add common __clk_get(), __clk_put() implementations

This patch adds common __clk_get(), __clk_put() clkdev helpers that
replace their platform specific counterparts when the common clock
API is used.

The owner module pointer field is added to struct clk so a reference
to the clock supplier module can be taken by the clock consumers.

The owner module is assigned while the clock is being registered,
in functions _clk_register() and __clk_register().

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
d6782c263661abd6c7e8a375141d69fdc457f9e1 23-Aug-2013 Sylwester Nawrocki <s.nawrocki@samsung.com> clk: Provide not locked variant of of_clk_get_from_provider()

Add helper functions for the of_clk_providers list locking and
an unlocked variant of of_clk_get_from_provider().
These functions are intended to be used in the clkdev to avoid
race condition in the device tree based clock look up in clk_get().

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
b5f98e65c0d887388eb9cbf55c76cb97fb4c2187 27-Nov-2013 Alex Elder <alex.elder@linaro.org> clk: clean up everything on debugfs error

[Maybe the third time will be the charm. -Alex]

If CONFIG_COMMON_CLK_DEBUG is defined, clk_debug_create_one() is
called to populate a debugfs directory with a few entries that are
common for all clock types.

If an error happens after creating the first one debugfs_remove() is
called on the clock's directory. The problem with this is that no
cleanup is done on the debugfs files already created in that
directory, so the directory never actually gets removed. This
problem is silently ignored.

Fix this by calling debugfs_remove_recursive() instead. Reset the
clk->dentry field to null afterward, to ensure it can't be mistaken
as a valid pointer.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
f61027426a5bc7093aa8359a411b053a35bb4b68 08-Oct-2013 Mike Turquette <mturquette@linaro.org> clk: of: helper for determining number of parent clocks

Walks the "clocks" array of parent clock phandles and returns the
number.

Signed-off-by: Mike Turquette <mturquette@linaro.org>
da0f0b2c3ad2ad9533c8c5cae84ad88d57a5e8dc 29-Sep-2013 Tomasz Figa <tomasz.figa@gmail.com> clk: Correct lookup logic in clk_fetch_parent_index()

This function is supposed to iterate over all parents of given child
clock to find the index of given parent clock in its parent list,
using parent cache if possible and falling back to string compare
otherwise. However currently the logic falls back to string compare in
every iteration in which clock cache entry does not match given parent,
due to wrong check conditions.

This patch corrects the logic to continue the loop if parent cache entry
is present and does not match requested parent clock. In addition,
redundant checks for parent cache array presence are removed, because it
is always allocated in the beginning of the function.

Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
96a7ed9079a3483c5681b17f4713c37c1cf2b1c9 29-Sep-2013 Tomasz Figa <tomasz.figa@gmail.com> clk: Use kcalloc() to allocate arrays

Instead of calculating sizes of arrays manually, kcalloc() can be used
to allocate arrays of elements with defined size. This is just a cleanup
patch without any functional changes.

Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
f1c8b2edf916b5be9dc29e98989a5eaff3c6e75b 29-Sep-2013 Tomasz Figa <tomasz.figa@gmail.com> clk: Add error handling to clk_fetch_parent_index()

There are at least two different error cases that can happen in
clk_fetch_parent_index() function:
- allocation failure,
- parent clock lookup failure,
however it returns only an u8, which is supposed to contain parent clock
index.

This patch modified the function to return full int instead allowing
positive clock indices and negative error codes to be returned. All
users of this function are adjusted as well to handle the return value
correctly.

Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
12d298865ec5d0f14dd570c3506c270880769ed7 05-Sep-2013 Alex Elder <alex.elder@linaro.org> clk: only call get_parent if there is one

In __clk_init(), after a clock is mostly initialized, a scan is done
of the orphan clocks to see if the clock being registered is the
parent of any of them.

This code assumes that any clock that provides a get_parent method
actually has at least one parent, and that's not a valid assumption.

As a result, an orphan clock with no parent can return *something*
as the parent index, and that value is blindly used to dereference
the orphan's parent_names[] array (which will be ZERO_SIZE_PTR or
NULL).

Fix this by ensuring get_parent is only called for orphans with at
least one parent.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
b05c683637fd538686030ec46c6717439d5571ab 03-Sep-2013 Thierry Reding <thierry.reding@gmail.com> clk: Move symbol export to proper location

The __clk_get_flags() symbol is exported immediately following the
clk_unprepare_unused_subtree() function. This is unusual, since a symbol
export typically follows body of the function that it exports.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
903efc553f738030a4ffa23fa03e7f329655c1c2 29-Aug-2013 James Hogan <james.hogan@imgtec.com> clk: fix new_parent dereference before null check

Commit 71472c0 (clk: add support for clock reparent on set_rate) added a
dereference of the new_parent pointer in clk_reparent(), but as detected
by smatch clk_reparent() later checks whether new_parent is NULL.

The dereference was in order to clear the new parent's new_child pointer
to avoid duplicate POST_RATE_CHANGE notifications, so clearly isn't
necessary if the new parent is NULL, so move it inside the "if
(new_parent)" block.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
7f7ed584d11be77a7521d170431bb14bc32a5980 22-Aug-2013 Alex Elder <alex.elder@linaro.org> clk: get matching entry under lock in of_clk_init()

Currently of_clk_init() finds a matching device node while holding
the device tree spinlock. When a matching device node is found, the
lock is dropped and then re-acquired in order to get a reference
to the matching device id structure.

Acquiring the spinlock twice is unnecessary (and it opens a
vulnerable window that could conceivably lead to errors).

There already exists an interface for both finding and taking a
reference to a device id under lock, so use it.

Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Christian Daudt <csd@broadcom.com>
Reviewed-by: Markus Mayer <markus.mayer@linaro.org>
Reviewed-by: Matt Porter <matt.porter@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
89ac8d7ae1cde0f8c7a2f85c2e3b475d54aa9163 22-Aug-2013 Mike Turquette <mturquette@linaro.org> clk: handle NULL struct clk gracefully

At some point changes to clk_set_rate and clk_set_parent introduced a
bug whereby NULL struct clk pointers were treated as an error. This is
in violation of the API in include/linux/clk.h. Reintroduce graceful
handling of NULL clk's by bailing from clk_set_rate and clk_set_parent
with return codes of zero.

Signed-off-by: Mike Turquette <mturquette@linaro.org>
e366fdd72529c545ccf327569ee250c1673be221 29-Jul-2013 James Hogan <james.hogan@imgtec.com> clk: clk-mux: implement remuxing on set_rate

Implement clk-mux remuxing if the CLK_SET_RATE_NO_REPARENT flag isn't
set. This implements determine_rate for clk-mux to propagate to each
parent and to choose the best one (like clk-divider this chooses the
parent which provides the fastest rate <= the requested rate).

The determine_rate op is implemented as a core helper function so that
it can be easily used by more complex clocks which incorporate muxes.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Mike Turquette <mturquette@linaro.org>
71472c0c06cf9a3d1540762ea205654c584e3bc4 29-Jul-2013 James Hogan <james.hogan@imgtec.com> clk: add support for clock reparent on set_rate

Add core support to allow clock implementations to select the best
parent clock when rounding a rate, e.g. the one which can provide the
closest clock rate to that requested. This is by way of adding a new
clock op, determine_rate(), which is like round_rate() but has an extra
parameter to allow the clock implementation to optionally select a
different parent clock. The core then takes care of reparenting the
clock when setting the rate.

The parent change takes place with the help of some new private data
members. struct clk::new_parent specifies a clock's new parent (NULL
indicates no change), and struct clk::new_child specifies a clock's new
child (whose new_parent member points back to it). The purpose of these
are to allow correct walking of the future tree for notifications prior
to actually reparenting any clocks, specifically to skip child clocks
who are being reparented to another clock (they will be notified via the
new parent), and to include any new child clock. These pointers are set
by clk_calc_subtree(), and the new_child pointer gets cleared when a
child is actually reparented to avoid duplicate POST_RATE_CHANGE
notifications.

Each place where round_rate() is called, determine_rate() is checked
first and called in preference. This restructures a few of the call
sites to simplify the logic into if/else blocks.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Mike Turquette <mturquette@linaro.org>
4935b22c46ea5e2dc44ef0b72db50741649eb3a4 29-Jul-2013 James Hogan <james.hogan@imgtec.com> clk: move some parent related functions upwards

Move some parent related functions up in clk.c so they can be used by
the modifications in the following patch which enables clock reparenting
during set_rate. No other changes are made so this patch makes no
functional difference in isolation. This is separate from the following
patch primarily to ease readability of that patch.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Mike Turquette <mturquette@linaro.org>
7ef3dcc8145263cb5a8c7059f82d44c948eb46a8 29-Jul-2013 James Hogan <james.hogan@imgtec.com> clk: abstract parent cache

Abstract access to the clock parent cache by defining
clk_get_parent_by_index(clk, index). This allows access to parent
clocks from clock drivers.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Mike Turquette <mturquette@linaro.org>
24ee1a083cbe0b0364a27404dc01a665b31839cb 29-Jun-2013 Peter Meerwald <pmeerw@pmeerw.net> clk: fix typos

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
f3aab5d61400b794ec759b9345e93e7ba57eb369 16-Apr-2013 Soren Brinkmann <soren.brinkmann@xilinx.com> clk: Always notify whole subtree when reparenting

A clock's notifier count only reflects notifiers which are registered
directly for that clock. A reparent operation though affects the whole
subtree because of a potential rate change.
When issuing the pre rate change notifications only the notifier count
for the clock to be changed is considered and notifiers for subclocks
may never be called. Resulting in clocks in the subtree which have
registered notifiers, may receive a POST_- or ABORT_RATE_CHANGE
notification, without a PRE_RATE_CHANGE_NOTIFICATION.
Therefore always traverse the whole subtree when issueing pre rate
change notifications during a reparent operation.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
34e452a152efd25d654b7bc809df429337115b03 05-Jun-2013 Peter De Schrijver <pdeschrijver@nvidia.com> clk: honor CLK_GET_RATE_NOCACHE in clk_set_rate

clk_set_rate() uses clk->rate directly. This causes problems if the clock
is marked as CLK_GET_RATE_NOCACHE. Hence call clk_get_rate() to get the
current rate.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
670decdd9544eddbc2ecf14789da4845f8afdab0 05-Jun-2013 Peter De Schrijver <pdeschrijver@nvidia.com> clk: use clk_get_rate() for debugfs

debugfs uses the rate field directly. However this ignores the
CLK_GET_RATE_NOCACHE flag. Call clk_get_rate() instead.

Tested-by: Mark Zhang <markz@nvidia.com>
Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
72b5322f11ff0abf6a52b3007486656578d2c982 03-Jun-2013 Lai Jiangshan <laijs@cn.fujitsu.com> clk: remove notifier from list before freeing it

The @cn is stay in @clk_notifier_list after it is freed, it cause
memory corruption.

Example, if @clk is registered(first), unregistered(first),
registered(second), unregistered(second).

The freed @cn will be used when @clk is registered(second),
and the bug will be happened when @clk is unregistered(second):

[ 517.040000] clk_notif_dbg clk_notif_dbg.1: clk_notifier_unregister()
[ 517.040000] Unable to handle kernel paging request at virtual address 00df3008
[ 517.050000] pgd = ed858000
[ 517.050000] [00df3008] *pgd=00000000
[ 517.060000] Internal error: Oops: 5 [#1] PREEMPT SMP ARM
[ 517.060000] Modules linked in: clk_notif_dbg(O-) [last unloaded: clk_notif_dbg]
[ 517.060000] CPU: 1 PID: 499 Comm: modprobe Tainted: G O 3.10.0-rc3-00119-ga93cb29-dirty #85
[ 517.060000] task: ee1e0180 ti: ee3e6000 task.ti: ee3e6000
[ 517.060000] PC is at srcu_readers_seq_idx+0x48/0x84
[ 517.060000] LR is at srcu_readers_seq_idx+0x60/0x84
[ 517.060000] pc : [<c0052720>] lr : [<c0052738>] psr: 80070013
[ 517.060000] sp : ee3e7d48 ip : 00000000 fp : ee3e7d6c
[ 517.060000] r10: 00000000 r9 : ee3e6000 r8 : 00000000
[ 517.060000] r7 : ed84fe4c r6 : c068ec90 r5 : c068e430 r4 : 00000000
[ 517.060000] r3 : 00df3000 r2 : 00000000 r1 : 00000002 r0 : 00000000
[ 517.060000] Flags: Nzcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
[ 517.060000] Control: 18c5387d Table: 2d85804a DAC: 00000015
[ 517.060000] Process modprobe (pid: 499, stack limit = 0xee3e6238)
[ 517.060000] Stack: (0xee3e7d48 to 0xee3e8000)
....
[ 517.060000] [<c0052720>] (srcu_readers_seq_idx+0x48/0x84) from [<c0052790>] (try_check_zero+0x34/0xfc)
[ 517.060000] [<c0052790>] (try_check_zero+0x34/0xfc) from [<c00528b0>] (srcu_advance_batches+0x58/0x114)
[ 517.060000] [<c00528b0>] (srcu_advance_batches+0x58/0x114) from [<c0052c30>] (__synchronize_srcu+0x114/0x1ac)
[ 517.060000] [<c0052c30>] (__synchronize_srcu+0x114/0x1ac) from [<c0052d14>] (synchronize_srcu+0x2c/0x34)
[ 517.060000] [<c0052d14>] (synchronize_srcu+0x2c/0x34) from [<c0053a08>] (srcu_notifier_chain_unregister+0x68/0x74)
[ 517.060000] [<c0053a08>] (srcu_notifier_chain_unregister+0x68/0x74) from [<c0375a78>] (clk_notifier_unregister+0x7c/0xc0)
[ 517.060000] [<c0375a78>] (clk_notifier_unregister+0x7c/0xc0) from [<bf008034>] (clk_notif_dbg_remove+0x34/0x9c [clk_notif_dbg])
[ 517.060000] [<bf008034>] (clk_notif_dbg_remove+0x34/0x9c [clk_notif_dbg]) from [<c02bb974>] (platform_drv_remove+0x24/0x28)
[ 517.060000] [<c02bb974>] (platform_drv_remove+0x24/0x28) from [<c02b9bf8>] (__device_release_driver+0x8c/0xd4)
[ 517.060000] [<c02b9bf8>] (__device_release_driver+0x8c/0xd4) from [<c02ba680>] (driver_detach+0x9c/0xc4)
[ 517.060000] [<c02ba680>] (driver_detach+0x9c/0xc4) from [<c02b99c4>] (bus_remove_driver+0xcc/0xfc)
[ 517.060000] [<c02b99c4>] (bus_remove_driver+0xcc/0xfc) from [<c02bace4>] (driver_unregister+0x54/0x78)
[ 517.060000] [<c02bace4>] (driver_unregister+0x54/0x78) from [<c02bbb44>] (platform_driver_unregister+0x1c/0x20)
[ 517.060000] [<c02bbb44>] (platform_driver_unregister+0x1c/0x20) from [<bf0081f8>] (clk_notif_dbg_driver_exit+0x14/0x1c [clk_notif_dbg])
[ 517.060000] [<bf0081f8>] (clk_notif_dbg_driver_exit+0x14/0x1c [clk_notif_dbg]) from [<c00835e4>] (SyS_delete_module+0x200/0x28c)
[ 517.060000] [<c00835e4>] (SyS_delete_module+0x200/0x28c) from [<c000edc0>] (ret_fast_syscall+0x0/0x48)
[ 517.060000] Code: e5973004 e7911102 e0833001 e2881002 (e7933101)

Cc: stable@kernel.org
Reported-by: Sören Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Tested-by: Sören Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: shortened $SUBJECT]
d41d5805875a628bdef75b624bab245da436f816 09-May-2013 Saravana Kannan <skannan@codeaurora.org> clk: Disable unused clocks after deferred probing is done

With deferred probing, late_initcall() is too soon to declare a clock as
unused. Wait for deferred probing to finish before declaring a clock as
unused. Since deferred probing is done in late_initcall(), do the unused
check to late_initcall_sync.

Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
f8aa0bd5c9b28f80bf372d0f486737b13ff01910 16-May-2013 Saravana Kannan <skannan@codeaurora.org> clk: Fix race condition between clk_set_parent and clk_enable()

Without this patch, the following race condition is possible.
* clk-A has two parents - clk-X and clk-Y.
* All three are disabled and clk-X is current parent.
* Thread A: clk_set_parent(clk-A, clk-Y).
* Thread A: <snip execution flow>
* Thread A: Grabs enable lock.
* Thread A: Sees enable count of clk-A is 0, so doesn't enable clk-Y.
* Thread A: Updates clk-A SW parent to clk-Y
* Thread A: Releases enable lock.
* Thread B: clk_enable(clk-A).
* Thread B: clk_enable() enables clk-Y, then enabled clk-A and returns.

clk-A is now enabled in software, but not clocking in hardware since the
hardware parent is still clk-X.

The only way to avoid race conditions between clk_set_parent() and
clk_enable/disable() is to ensure that clk_enable/disable() calls don't
require changes to hardware enable state between changes to software clock
topology and hardware clock topology.

The options to achieve the above are:
1. Grab the enable lock before changing software/hardware topology and
release it afterwards.
2. Keep the clock enabled for the duration of software/hardware topology
change so that any additional enable/disable calls don't try to change
the hardware state. Once the topology change is complete, the clock can
be put back in its original enable state.

Option (1) is not an acceptable solution since the set_parent() ops might
need to sleep.

Therefore, this patch implements option (2).

This patch doesn't violate any API semantics. clk_disable() doesn't
guarantee that the clock is actually disabled. So, no clients of a clock
can assume that a clock is disabled after their last call to clk_disable().
So, enabling the clock during a parent change is not a violation of any API
semantics.

This also has the nice side effect of simplifying the error handling code.

Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: fixed up whitespace issue]
1e435256d625c203660f0105f1155cd2af283051 27-Apr-2013 Olof Johansson <olof@lixom.net> clk: add clk_ignore_unused option to keep boot clocks on

This is primarily useful when there's a driver that doesn't claim clocks
properly, but the bootloader leaves them on. It's not expected to be used
in normal cases, but for bringup and debug it's very useful to have the
option to not gate unclaimed clocks that are still on.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: fixed up trivial merge issue]
496620ccf8905b39058adc998475125325a7e753 15-Apr-2013 Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com> clk: export __clk_get_flags for modular clock providers

The common clock api provides some helpers for clk-providers but does
not export these helpers. This hinders clk-providers to be built as modules.
This patch adds __clk_get_flags() to the list of exported symbols.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
fb72a0590b770f7da6a02bde6b8a147a3d9f6168 03-Apr-2013 Soren Brinkmann <soren.brinkmann@xilinx.com> clk: Properly handle notifier return values

Notifiers may return NOTIFY_(OK|DONE|STOP|BAD). The CCF uses an
inconsistent mix of checking against NOTIFY_STOP or NOTIFY_BAD.
This inconsistency leaves errors undetected in some cases:
clk_set_parent() calls __clk_speculate_rates(), which stops when it
hits a NOTIFIER_BAD (STOP is ignored), and passes this value back to the
caller.
clk_set_parent() compares this return value against NOTIFY_STOP only,
ignoring NOTIFY_BAD returns.

Use NOTIFY_STOP_MASK to detect a negative notifier return value and
document all four return value options.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
a68de8e4ab2756d8e125cf327f044c895b6a6b3d 02-Apr-2013 Ulf Hansson <ulf.hansson@linaro.org> clk: Fixup locking issues for clk_set_parent

Updating the clock tree topology must be protected with the spinlock
when doing clk_set_parent, otherwise we can not handle the migration
of the enable_count in a safe manner.

While issuing the .set_parent callback to make the clk-hw perform the
switch to the new parent, we can not hold the spinlock since it is must
be allowed to be slow path. This complicates error handling, but is still
possible to achieve.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
031dcc9bd4164a7482b89987d5b9ecb3af5e9033 02-Apr-2013 Ulf Hansson <ulf.hansson@linaro.org> clk: Fixup errorhandling for clk_set_parent

Fixup the broken feature of allowing reparent of a clk to the
orhpan list and vice verse. When operating on a single-parent
clk, the .set_parent callback for the clk hw is optional to
implement, but for a multi-parent clk it is mandatory.

Moreover improve the errorhandling by verifying the prerequisites
before triggering clk notifiers. This will prevent unnecessary
rollback with ABORT_RATE_CHANGE.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
b33d212f4910ca44bd37d5e08422230687bd1378 02-Apr-2013 Ulf Hansson <ulf.hansson@linaro.org> clk: Restructure code for __clk_reparent

Split __clk_reparent into three pieces, one for doing the actual
reparent for updating the clock tree topology, one for the
COMMON_CLK_DEBUG code and one for doing the rate recalculation.

This patch also makes it possible to hold the spinlock over the
update of the clock tree topology, which could not be done before
when both debugfs updates and clock rate updates was done within
the same function.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
533ddeb1e86f506129ee388a6cc13796dcf31311 28-Mar-2013 Mike Turquette <mturquette@linaro.org> clk: allow reentrant calls into the clk framework

Reentrancy into the clock framework is necessary for clock operations
that result in nested calls to the clk api. A common example is a clock
that is prepared via an i2c transaction, such as a clock inside of a
discrete audio chip or a power management IC. The i2c subsystem itself
will use the clk api resulting in a deadlock:

clk_prepare(audio_clk)
i2c_transfer(..)
clk_prepare(i2c_controller_clk)

The ability to reenter the clock framework prevents this deadlock.

Other use cases exist such as allowing .set_rate callbacks to call
clk_set_parent to achieve the best rate, or to save power in certain
configurations. Yet another example is performing pinctrl operations
from a clk_ops callback. Calls into the pinctrl subsystem may call
clk_{un}prepare on an unrelated clock. Allowing for nested calls to
reenter the clock framework enables both of these use cases.

Reentrancy is implemented by two global pointers that track the owner
currently holding a global lock. One pointer tracks the owner during
sleepable, mutex-protected operations and the other one tracks the owner
during non-interruptible, spinlock-protected operations.

When the clk framework is entered we try to hold the global lock. If it
is held we compare the current task against the current owner; a match
implies a nested call and we reenter. If the values do not match then
we block on the lock until it is released.

Signed-off-by: Mike Turquette <mturquette@linaro.org>
Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org>
Cc: David Brown <davidb@codeaurora.org>
Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
eab89f690ee0805c02017d7959f4f930379a8c46 28-Mar-2013 Mike Turquette <mturquette@linaro.org> clk: abstract locking out into helper functions

Create locking helpers for the global mutex and global spinlock. The
definitions of these helpers will be expanded upon in the next patch
which introduces reentrancy into the locking scheme.

Signed-off-by: Mike Turquette <mturquette@linaro.org>
Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org>
Cc: David Brown <davidb@codeaurora.org>
Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
5fda6858a49c2d8706adcc05f083b64af172d3eb 13-Mar-2013 Sachin Kamat <sachin.kamat@linaro.org> clk: Fix incorrect return type in clk.c

Return type of function clk_propagate_rate_change is a pointer.
But 0 was being returned. Change it to NULL.
Silences the following warning:
drivers/clk/clk.c:977:24: warning: Using plain integer as NULL pointer

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Reviewed-by: Pankaj Jangra <jangra.pankaj9@gmail.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
3cc8247f1dce79511de8bf0f69ab02a46cc315b7 12-Mar-2013 Ulf Hansson <ulf.hansson@linaro.org> clk: Introduce optional unprepare_unused callback

An unprepare_unused callback is introduced due to the same reasons to
why the disable_unused callback was added.

During the clk_disable_unused sequence, those clk_hw that needs specific
treatment with regards to being unprepared, shall implement the
unprepare_unused callback.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
1c155b3dfe08351f5fc811062648969f1ba7af53 12-Mar-2013 Ulf Hansson <ulf.hansson@linaro.org> clk: Unprepare the unused prepared slow clocks at late init

The unused ungated fast clocks are already being disabled from
clk_disable_unused at late init. This patch extend this sequence
to the slow unused prepared clocks to be unprepared.

Unless the optional .is_prepared callback is implemented by a
clk_hw the clk_disable_unused sequence will not unprepare any
unused clocks, since it will fall back to use the software
prepare counter.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: fixed hlist accessors per b67bfe0d]
3d6ee287a3e341c88eafd0b4620b12d640b3736b 12-Mar-2013 Ulf Hansson <ulf.hansson@linaro.org> clk: Introduce optional is_prepared callback

To reflect whether a clk_hw is prepared the clk_hw may implement
the optional is_prepared callback. If not implemented we fall back
to use the software prepare counter.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
b67bfe0d42cac56c512dd5da4b1b347a23f4b70a 28-Feb-2013 Sasha Levin <sasha.levin@oracle.com> hlist: drop the node parameter from iterators

I'm not sure why, but the hlist for each entry iterators were conceived

list_for_each_entry(pos, head, member)

The hlist ones were greedy and wanted an extra parameter:

hlist_for_each_entry(tpos, pos, head, member)

Why did they need an extra pos parameter? I'm not quite sure. Not only
they don't really need it, it also prevents the iterator from looking
exactly like the list iterator, which is unfortunate.

Besides the semantic patch, there was some manual work required:

- Fix up the actual hlist iterators in linux/list.h
- Fix up the declaration of other iterators based on the hlist ones.
- A very small amount of places were using the 'node' parameter, this
was modified to use 'obj->member' instead.
- Coccinelle didn't handle the hlist_for_each_entry_safe iterator
properly, so those had to be fixed up manually.

The semantic patch which is mostly the work of Peter Senna Tschudin is here:

@@
iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host;

type T;
expression a,c,d,e;
identifier b;
statement S;
@@

-T b;
<+... when != b
(
hlist_for_each_entry(a,
- b,
c, d) S
|
hlist_for_each_entry_continue(a,
- b,
c) S
|
hlist_for_each_entry_from(a,
- b,
c) S
|
hlist_for_each_entry_rcu(a,
- b,
c, d) S
|
hlist_for_each_entry_rcu_bh(a,
- b,
c, d) S
|
hlist_for_each_entry_continue_rcu_bh(a,
- b,
c) S
|
for_each_busy_worker(a, c,
- b,
d) S
|
ax25_uid_for_each(a,
- b,
c) S
|
ax25_for_each(a,
- b,
c) S
|
inet_bind_bucket_for_each(a,
- b,
c) S
|
sctp_for_each_hentry(a,
- b,
c) S
|
sk_for_each(a,
- b,
c) S
|
sk_for_each_rcu(a,
- b,
c) S
|
sk_for_each_from
-(a, b)
+(a)
S
+ sk_for_each_from(a) S
|
sk_for_each_safe(a,
- b,
c, d) S
|
sk_for_each_bound(a,
- b,
c) S
|
hlist_for_each_entry_safe(a,
- b,
c, d, e) S
|
hlist_for_each_entry_continue_rcu(a,
- b,
c) S
|
nr_neigh_for_each(a,
- b,
c) S
|
nr_neigh_for_each_safe(a,
- b,
c, d) S
|
nr_node_for_each(a,
- b,
c) S
|
nr_node_for_each_safe(a,
- b,
c, d) S
|
- for_each_gfn_sp(a, c, d, b) S
+ for_each_gfn_sp(a, c, d) S
|
- for_each_gfn_indirect_valid_sp(a, c, d, b) S
+ for_each_gfn_indirect_valid_sp(a, c, d) S
|
for_each_host(a,
- b,
c) S
|
for_each_host_safe(a,
- b,
c, d) S
|
for_each_mesh_entry(a,
- b,
c, d) S
)
...+>

[akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c]
[akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c]
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foudnation.org: redo intrusive kvm changes]
Tested-by: Peter Senna Tschudin <peter.senna@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
f2f6c2556dcc432e50003bc8fa4d62d95906f149 03-Jan-2013 Prashant Gaikwad <pgaikwad@nvidia.com> clk: add common of_clk_init() function

Modify of_clk_init function so that it will determine which
driver to initialize based on device tree instead of each driver
registering to it.

Based on a similar patch for drivers/irqchip by Thomas Petazzoni and
drivers/clocksource by Stephen Warren.

Signed-off-by: Prashant Gaikwad <pgaikwad@nvidia.com>
Tested-by: Tony Prisk <linux@prisktech.co.nz>
Tested-by: Pawel Moll <pawel.moll@arm.com>
Tested-by: Rob Herring <rob.herring@calxeda.com>
Tested-by: Josh Cartwright <josh.cartwright@ni.com>
Reviewed-by: Josh Cartwright <josh.cartwright@ni.com>
Acked-by: Maxime Ripard <maxime.ripard@anandra.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: merge conflict from missing CLKSRC_OF_TABLES()]

Signed-off-by: Mike Turquette <mturquette@linaro.org>
4cfe54e57910b59444d34a05284db27df416f20b 18-Jan-2013 Nestor Ovroy <novroy@riseup.net> clk: Deduplicate exit code in clk_set_rate

On non-out case 'return ret;' is equivalent to 'return 0;' as the ret
variable is initialized at 0 and never changed.

Signed-off-by: Nestor Ovroy <novroy@riseup.net>
bddca8944a7ab6699984c4b1b677261eb1c8d819 26-Dec-2012 Prashant Gaikwad <pgaikwad@nvidia.com> clk: JSON debugfs clock tree summary

Clock information is dumped in JSON format which is easy
for machines to parse.

Each clock is represented as an object which has same name as
clock and following properties
- enable_count
- prepare_count
- rate

Output is verified using online JSON editor.

Signed-off-by: Prashant Gaikwad <pgaikwad@nvidia.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
1af599df6bdad9ee34ae9e50efcda273e12b9d4f 26-Dec-2012 Prashant Gaikwad <pgaikwad@nvidia.com> clk: human-readable debugfs clock tree summary

Adds debug file "clk_summary" in /sys/kernel/debug/clk dir.
It helps to view all the clock registered in human-readable format.

For example:
clock enable_cnt prepare_cnt rate
---------------------------------------------------------------------
i2s0_sync 0 0 24000000
spdif_in_sync 0 0 24000000
spdif_mux 0 0 24000000
spdif 0 0 24000000
spdif_doubler 0 0 48000000
spdif_div 0 0 48000000
spdif_2x 0 0 48000000
clk_32k 2 2 32768
blink_override 1 1 32768
blink 1 1 32768
clk_m 2 2 12000000
clk_out_3_mux 0 0 12000000
clk_out_3 0 0 12000000
pll_ref 3 3 12000000
pll_e_mux 0 0 12000000
pll_e 0 0 100000000
cml0 0 0 100000000
cml1 0 0 100000000
pciex 0 0 100000000
pll_d2 0 0 1000000
pll_d2_out0 0 0 500000
pll_d 0 0 1000000
pll_d_out0 0 0 500000
dsib_mux 0 0 500000
dsib 0 0 500000
dsia 0 0 500000

Signed-off-by: Prashant Gaikwad <pgaikwad@nvidia.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
4895084c87ab0973308021d755596798160b682a 13-Dec-2012 Niels de Vos <ndevos@redhat.com> clk: export __clk_get_name for re-use in imx-ipu-v3 and others

This fixes the following error when building for arm-imx:
> ERROR: "__clk_get_name" [drivers/staging/imx-drm/ipu-v3/imx-ipu-v3.ko] undefined!
> make[1]: *** [__modpost] Error 1
> make: *** [modules] Error 2

There are valid usecases to get the name of a clock, be it for debugging
purposes or to register a children of a clock like done in this IPU driver.
Therefore exporting __clk_get_name() and make it available for others makes
sense.

Reported-by: Peter Robinson <pbrobinson@gmail.com>
CC: Sascha Hauer <s.hauer@pengutronix.de>
CC: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Niels de Vos <ndevos@redhat.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: removal of inline made redundant by 65800b2]
65800b2c4012e11f1c33692e6727e743a05c6efe 26-Nov-2012 Russ Dill <Russ.Dill@ti.com> clk: Don't mark shared helper functions as inline

The helper functions that access the opaque struct clk should
not be marked inline since they are contained in clk.c, but expected
to be used by other compilation units. This causes compile errors
under gcc-4.7

In file included from arch/arm/mach-omap2/clockdomain.c:25:0:
arch/arm/mach-omap2/clockdomain.c: In function ‘clkdm_clk_disable’:
include/linux/clk-provider.h:338:12: error: inlining failed in call to always_inline ‘__clk_get_enable_count’: function body not available
arch/arm/mach-omap2/clockdomain.c:1001:28: error: called from here
make[1]: *** [arch/arm/mach-omap2/clockdomain.o] Error 1
make: *** [arch/arm/mach-omap2] Error 2

Signed-off-by: Russ Dill <Russ.Dill@ti.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: removed fixes made redundant by commit 93532c8a]
[mturquette@linaro.org: improved $SUBJECT]
7c045a55c97fb83a2e5e9c6c857162c4866cc602 04-Dec-2012 Mike Turquette <mturquette@linaro.org> clk: introduce optional disable_unused callback

Some gate clocks have special needs which must be handled during the
disable-unused clocks sequence. These needs might be driven by software
due to the fact that we're disabling a clock outside of the normal
clk_disable path and a clk's enable_count will not be accurate. On the
other hand a specific hardware programming sequence might need to be
followed for this corner case.

This change is needed for the upcoming OMAP port to the common clock
framework. Specifically, it is undesirable to treat the disable-unused
path identically to the normal clk_disable path since other software
layers are involved. In this case OMAP's clockdomain code throws WARNs
and bails early due to the clock's enable_count being set to zero. A
custom callback mitigates this problem nicely.

Cc: Paul Walmsley <paul@pwsan.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
1f61e5f143b578606389887887af549bc5554353 22-Nov-2012 Martin Fuzzey <mfuzzey@parkeon.com> clk: clock multiplexers may register out of order

When a clock, C is initialised any orphan clocks listing C as
a possible parent are reparented to it regardless of the
parent requested by the orphan's get_parent() operation.

This means that multiplexers registered before their parents
are reparented to the first parent subsequently declared,
regardless of the selection made by the hardware registers.

For example:
static const char *sel[] = { "srcA", "srcB", "dummy", "srcC" };

child = clk_register_mux(NULL, "child", sel, ARRAY_SIZE(sel), ...);
clk_register_fixed(NULL, "dummy", ...);
clk_register_fixed(NULL, "srcA", ...);
clk_register_fixed(NULL, "srcB", ...);
clk_register_fixed(NULL, "srcC", ...);

Causes child's parent to always be "dummy".

To fix this, when an orphanned clock has a get_parent() operation,
only reparent to the clock indicated by get_parent().

Signed-off-by: Martin Fuzzey <mfuzzey@parkeon.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: improve $SUBJECT]
46c8773a58010d31f228e148b8b774d94cc9810d 24-Sep-2012 Stephen Boyd <sboyd@codeaurora.org> clk: Add devm_clk_{register,unregister}()

Some clock drivers can be simplified if devres takes care of
unregistering any registered clocks along error paths. Introduce
devm_clk_register() so that clock drivers get unregistration for
free along with simplified error paths.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
2ac6b1f50a397580b8dc28f2833e54af7926fc71 04-Oct-2012 Stephen Boyd <sboyd@codeaurora.org> clk: Don't return negative numbers for unsigned values with !clk

Some of the helper functions return negative error codes if
passed a NULL clock. This can lead to confusing behavior when the
expected return value is unsigned. Fix up these accessors so that
they return unsigned values (or bool in the case of is_enabled).
This way we can't interpret NULL clocks as having valid and
interesting values.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
494bfec99922d54054d2d0873f1017680cfc3f13 22-Aug-2012 Shawn Guo <shawn.guo@linaro.org> clk: add of_clk_src_onecell_get() support

For those SoCs that have hundreds of clock outputs, their clock
DT bindings could reasonably define #clock-cells as 1 and require
the client device specify the index of the clock it consumes in the
cell of its "clocks" phandle.

Add a generic of_clk_src_onecell_get() function for this purpose.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Reviewed-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
a093bde2b45a0a745f12c018e2d13c027d58641f 31-Aug-2012 Ulf Hansson <ulf.hansson@linaro.org> clk: Provide option for clk_get_rate to issue hw for new rate

By using CLK_GET_RATE_NOCACHE flag, we tell the clk_get_rate API to
issue the hw for an updated clock rate. This can be used for a clock
which rate may be updated without a client necessary modifying it.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
e47c6a3408ea6bcfc5204f23d5a5b209de6e68b9 30-Jul-2012 Fengguang Wu <fengguang.wu@intel.com> clk: validate pointer in __clk_disable()

clk_get() returns -ENOENT on error and some careless caller might
dereference it without error checking:

In mxc_rnga_remove():

struct clk *clk = clk_get(&pdev->dev, "rng");

// ...

clk_disable(clk);

Since it's insane to audit the lots of existing and future clk users,
let's add a check in the callee to avoid kernel panic and warn about
any buggy user.

Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Viresh Kumar <viresh.kumar@st.com>
Cc: viresh kumar <viresh.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
766e6a4ec602d0c107553b91b3434fe9c03474f4 09-Apr-2012 Grant Likely <grant.likely@secretlab.ca> clk: add DT clock binding support

Based on work 1st by Ben Herrenschmidt and Jeremy Kerr, then by Grant
Likely, this patch adds support to clk_get to allow drivers to retrieve
clock data from the device tree.

Platforms scan for clocks in DT with of_clk_init and a match table, and
the register a provider through of_clk_add_provider. The provider's
clk_src_get function will be called when a device references the
provider's OF node for a clock reference.

v6 (Rob Herring):
- Return error values instead of NULL to match clock framework
expectations

v5 (Rob Herring):
- Move from drivers/of into common clock subsystem
- Squashed "dt/clock: add a simple provider get function" and
"dt/clock: add function to get parent clock name"
- Rebase to 3.4-rc1
- Drop CONFIG_OF_CLOCK and just use CONFIG_OF
- Add missing EXPORT_SYMBOL to various functions
- s/clock-output-name/clock-output-names/
- Define that fixed-clock binding is a single output

v4 (Rob Herring):
- Rework for common clk subsystem
- Add of_clk_get_parent_name function

v3: - Clarified documentation

v2: - fixed errant ';' causing compile error
- Editorial fixes from Shawn Guo
- merged in adding lookup to clkdev
- changed property names to match established convention. After
working with the binding a bit it really made more sense to follow the
lead of 'reg', 'gpios' and 'interrupts' by making the input simply
'clocks' & 'clock-names' instead of 'clock-input-*', and to only use
clock-output* for the producer nodes. (Sorry Shawn, this will mean
you need to change some code, but it should be trivial)
- Add ability to inherit clocks from parent nodes by using an empty
'clock-ranges' property. Useful for busses. I could use some feedback
on the new property name, 'clock-ranges' doesn't feel right to me.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Reviewed-by: Shawn Guo <shawn.guo@freescale.com>
Cc: Sascha Hauer <kernel@pengutronix.de>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
9ca1c5a4bf4105d6f2f2a46892495953dd3e2fec 06-Jun-2012 Rajendra Nayak <rnayak@ti.com> clk: cache parent clocks only for muxes

caching parent clocks makes sense only when a clock has more
than one parent (mux clocks).
Avoid doing this for every other clock.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
[mturquette@linaro.org: removed extra parentheses]
Signed-off-by: Mike Turquette <mturquette@linaro.org>
863b13271f1608ab3af6f7a371047d9a66693e38 02-Jul-2012 Rajendra Nayak <rnayak@ti.com> clk: fix parent validation in __clk_set_parent()

The below commit introduced a bug in __clk_set_parent()
which could cause it to *skip* the parent validation
which makes sure the parent passed to the api is a valid
one.

commit 7975059db572eb47f0fb272a62afeae272a4b209
Author: Rajendra Nayak <rnayak@ti.com>
Date: Wed Jun 6 14:41:31 2012 +0530

clk: Allow late cache allocation for clk->parents

This was identified by the following compiler warning..

drivers/clk/clk.c: In function '__clk_set_parent':
drivers/clk/clk.c:1083:5: warning: 'i' may be used uninitialized in this function [-Wuninitialized]

.. as reported by Marc Kleine-Budde.

There were various options discussed on how to fix this, one
being initing 'i' to clk->num_parents, but the below approach
was found to be more appropriate as it also makes the 'parent
validation' code simpler to read.

Reported-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Cc: stable@kernel.org
bf47b4fd8f9f81cd5ce40e1945c6334d088226d1 08-Jun-2012 Pawel Moll <pawel.moll@arm.com> clk: Check parent for NULL in clk_change_rate

clk_change_rate() is accessing parent's rate without checking
if the parent exists at all. In case of root clocks this will
cause NULL pointer dereference.

This patch follows what clk_calc_new_rates() does in such
situation.

Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Cc: stable@kernel.org
7975059db572eb47f0fb272a62afeae272a4b209 06-Jun-2012 Rajendra Nayak <rnayak@ti.com> clk: Allow late cache allocation for clk->parents

Parent clocks for muxes are cached in clk->parents to
avoid frequent lookups, however the cache allocation happens
only during clock registeration and later clk_set_parent()
assumes a cache space available and allocated.

This is not entirely true for platforms which do early clock
registerations wherein the cache allocation using kzalloc
could fail during clock registeration.

Allow cache allocation to happen later as part of clk_set_parent()
to help such cases and avoid crashes assuming a cache being
available.

While here also replace existing kmalloc() with kzalloc()
in the file.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Cc: stable@kernel.org
7e0fa1b5fa91d9aa456d102c273b2cf0f2e95d39 15-May-2012 Saravana Kannan <skannan@codeaurora.org> clk: Fix CLK_SET_RATE_GATE flag validation in clk_set_rate().

The clk_set_rate() code shouldn't check the clock's enable count when
validating CLK_SET_RATE_GATE flag since the enable count could change after
the validation. Similar to clk_set_parent(), it should instead check the
prepare count. The prepare count should go to zero only when the end user
expects the clock to not be enabled in the future. Since the code already
grabs the prepare count before validation, it's not possible for prepare
count to change after validation and by association not possible for a well
behaving end user to enable the clock while the set rate is in progress.

Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
Reviewed-by: Richard Zhao <richard.zhao@freescale.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
1df5c939f6d9dff7dfbe108d93133b9636baa607 18-Apr-2012 Mark Brown <broonie@opensource.wolfsonmicro.com> clk: Provide dummy clk_unregister()

While there's no actual implementation behind it having the call to use
in drivers makes them feel neater from a driver author point of view. An
actual implementation can wait for someone who needs to use the function
in a real system.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
[mturquette@linaro.org: void return type instead of int -EINVAL]
Signed-off-by: Mike Turquette <mturquette@linaro.org>
d269b974e32c5dcf043acd07f9ad96e715019ffd 03-May-2012 Mike Turquette <mturquette@linaro.org> clk: remove COMMON_CLK_DISABLE_UNUSED

Exposing this option generates confusion and incorrect behavior for
single-image builds across platforms. Enable this behavior permanently.

Signed-off-by: Mike Turquette <mturquette@linaro.org>
Acked-by: Saravana Kannan <skannan@codeaurora.org>
63f5c3b2b18dcaca0fc8983b52a3f5d4d70a0590 03-May-2012 Mike Turquette <mturquette@linaro.org> clk: prevent spurious parent rate propagation

Patch 'clk: always pass parent_rate into .round_rate' made a subtle
change to the semantics of .round_rate. It is now expected for the
parent's rate to always be passed in, simplifying the implemenation of
various .round_rate callback definitions.

However the patch also introduced a bug in clk_calc_new_rates whereby a
clock without the CLK_SET_RATE_PARENT flag set could still propagate a
rate change up to a parent clock if the the .round_rate callback
modified the &best_parent_rate value in any way.

This patch fixes the issue at the framework level (in
clk_calc_new_rates) by specifically handling the case where the
CLK_SET_RATE_PARENT flag is not set.

Signed-off-by: Mike Turquette <mturquette@linaro.org>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
0e1c03017549a9df513622b3f15ff38eb8d35a62 11-Apr-2012 Viresh Kumar <viresh.kumar@st.com> clk: clk_set_rate() must fail if CLK_SET_RATE_GATE is set and clk is enabled

This is well documented but isn't implemented. clk_set_rate() must check if
flags have CLK_SET_RATE_GATE bit set and is enabled too.

Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
0197b3ea0f66cd2a11417f58fe1812858ea77908 26-Apr-2012 Saravana Kannan <skannan@codeaurora.org> clk: Use a separate struct for holding init data.

Create a struct clk_init_data to hold all data that needs to be passed from
the platfrom specific driver to the common clock framework during clock
registration. Add a pointer to this struct inside clk_hw.

This has several advantages:
* Completely hides struct clk from many clock platform drivers and static
clock initialization code that don't care for static initialization of
the struct clks.
* For platforms that want to do complete static initialization, it removed
the need to directly mess with the struct clk's fields while still
allowing to statically allocate struct clk. This keeps the code more
future proof even if they include clk-private.h.
* Simplifies the generic clk_register() function and allows adding optional
fields in the future without modifying the function signature.
* Simplifies the static initialization of clocks on all platforms by
removing the need for forward delcarations or convoluted macros.

Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
[mturquette@linaro.org: kept DEFINE_CLK_* macros and __clk_init]
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Jeremy Kerr <jeremy.kerr@canonical.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnd Bergman <arnd.bergmann@linaro.org>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Shawn Guo <shawn.guo@freescale.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Jamie Iles <jamie@jamieiles.com>
Cc: Richard Zhao <richard.zhao@linaro.org>
Cc: Saravana Kannan <skannan@codeaurora.org>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Linus Walleij <linus.walleij@stericsson.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Amit Kucheria <amit.kucheria@linaro.org>
Cc: Deepak Saxena <dsaxena@linaro.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
1b2f99037a29d48d03ddd2fd0dc117888ec737f4 17-Apr-2012 Viresh Kumar <viresh.kumar@st.com> clk: Don't set clk->new_rate twice

if (!clk->ops->round_rate && (clk->flags & CLK_SET_RATE_PARENT)) is true, then
we don't need to set clk->new_rate here, as we will call clk_calc_subtree()
afterwards and it also sets clk->new_rate.

Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
f4d8af2e5ae6294d5e2220d3963def6f7ffc0873 12-Apr-2012 Shawn Guo <shawn.guo@linaro.org> clk: propagate round_rate for CLK_SET_RATE_PARENT case

Need to propagate round_rate call for the clk that has no .round_rate
operation but with flag CLK_SET_RATE_PARENT set.

For example, clk_mux is a clk with no .round_rate operation. However,
it could likely be in a clk_set_rate propagation path, saying it has
parent clk who has .round_rate and .set_rate operations.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
1c0035d710dd3bfa86d58f851b8737c7f11a9bbc 12-Apr-2012 Shawn Guo <shawn.guo@linaro.org> clk: pass parent_rate into .set_rate

For most of .set_rate implementation, parent_rate will be used, so just
like passing parent_rate into .recalc_rate, let's pass parent_rate into
.set_rate too.

It also updates the kernel doc for .set_rate ops.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
81536e072b54e30bbfd1a9a6b8094f7b3dd5321c 12-Apr-2012 Shawn Guo <shawn.guo@linaro.org> clk: always pass parent_rate into .round_rate

The parent_rate will likely be used by most .round_rate implementation
no matter whether flag CLK_SET_RATE_PARENT is set or not, so let's
always pass parent_rate into .round_rate.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
d1302a36a7f1c33d1a8babc6a510e1401a5e5aed 29-Mar-2012 Mike Turquette <mturquette@linaro.org> clk: core: copy parent_names & return error codes

This patch cleans up clk_register and solves a few bugs by teaching
clk_register and __clk_init to return error codes (instead of just NULL)
to better align with the existing clk.h api.

Along with that change this patch also introduces a new behavior whereby
clk_register copies the parent_names array, thus allowing platforms to
declare their parent_names arrays as __initdata.

Signed-off-by: Mike Turquette <mturquette@linaro.org>
d305fb78f31209596c9135d396a0d3af7ac86947 21-Mar-2012 Mark Brown <broonie@opensource.wolfsonmicro.com> clk: Constify parent name arrays

Drivers should be able to declare their arrays of parent names as const
so the APIs need to accept const arguments.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
[mturquette@linaro.org: constified gate]
Signed-off-by: Mike Turquette <mturquette@linaro.org>
34e44fe87437b6a5aad856f15f7a849e5fc137aa 26-Mar-2012 Rajendra Nayak <rnayak@ti.com> clk: Make clk_get_rate() return 0 on error

Most users of clk_get_rate() actually assume a non zero
return value as a valid rate returned. Returing -EINVAL
might confuse such users, so make it instead return zero
on error.

Besides the return value of clk_get_rate seems to be
'unsigned long'.

Signed-off-by: Rajendra nayak <rnayak@ti.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
d4d7e3ddc76c5ae3b4fbd15cb6f30aa78c28d788 27-Mar-2012 Mike Turquette <mturquette@linaro.org> clk: core: enforce clk_ops consistency

Documentation/clk.txt has some handsome ASCII art outlining which
clk_ops are mandatory for a given clock, given the capability of the
hardware. Enforce those mandates with sanity checks in __clk_init.

Signed-off-by: Mike Turquette <mturquette@linaro.org>
7452b2191cd55fb3fd6ad65344466ddcdbe4676e 26-Mar-2012 Mike Turquette <mturquette@linaro.org> clk: core: clk_calc_new_rates handles NULL parents

It is possible to call clk_set_rate on a clock with a NULL parent. One
such example is an adjustable-rate root clock. Ensure that
clk_calc_new_rates does not dereference parent without checking first
and also handle the corner cases gracefully.

Reported-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
70d347e6cd0d2a7ecc023b44ef721bc2c2a38f22 26-Mar-2012 Mike Turquette <mturquette@linaro.org> clk: core: remove dead code paths

Some static inline dummy functions were left over from before the clock
core was consolidated from several C files down to one. Remove them.

Reported-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
5654dc94f872f823aa13941a8fdba69a3feca39c 26-Mar-2012 Mike Turquette <mturquette@linaro.org> clk: core: correct clk_set_rate kerneldoc

Remove old and misleading documentation from the previous clk_set_rate
implementaion.

Reported-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
b2476490ef11134b65544d8f062cff96c53e941b 16-Mar-2012 Mike Turquette <mturquette@linaro.org> clk: introduce the common clock framework

The common clock framework defines a common struct clk useful across
most platforms as well as an implementation of the clk api that drivers
can use safely for managing clocks.

The net result is consolidation of many different struct clk definitions
and platform-specific clock framework implementations.

This patch introduces the common struct clk, struct clk_ops and an
implementation of the well-known clock api in include/clk/clk.h.
Platforms may define their own hardware-specific clock structure and
their own clock operation callbacks, so long as it wraps an instance of
struct clk_hw.

See Documentation/clk.txt for more details.

This patch is based on the work of Jeremy Kerr, which in turn was based
on the work of Ben Herrenschmidt.

Signed-off-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Mike Turquette <mturquette@ti.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Rob Herring <rob.herring <at> calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Jeremy Kerr <jeremy.kerr@canonical.com>
Cc: Arnd Bergman <arnd.bergmann@linaro.org>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Shawn Guo <shawn.guo@freescale.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Richard Zhao <richard.zhao@linaro.org>
Cc: Saravana Kannan <skannan@codeaurora.org>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Linus Walleij <linus.walleij@stericsson.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Amit Kucheria <amit.kucheria@linaro.org>
Cc: Deepak Saxena <dsaxena@linaro.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>