clk-provider.h revision 1c0035d710dd3bfa86d58f851b8737c7f11a9bbc
1/* 2 * linux/include/linux/clk-provider.h 3 * 4 * Copyright (c) 2010-2011 Jeremy Kerr <jeremy.kerr@canonical.com> 5 * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 */ 11#ifndef __LINUX_CLK_PROVIDER_H 12#define __LINUX_CLK_PROVIDER_H 13 14#include <linux/clk.h> 15 16#ifdef CONFIG_COMMON_CLK 17 18/** 19 * struct clk_hw - handle for traversing from a struct clk to its corresponding 20 * hardware-specific structure. struct clk_hw should be declared within struct 21 * clk_foo and then referenced by the struct clk instance that uses struct 22 * clk_foo's clk_ops 23 * 24 * clk: pointer to the struct clk instance that points back to this struct 25 * clk_hw instance 26 */ 27struct clk_hw { 28 struct clk *clk; 29}; 30 31/* 32 * flags used across common struct clk. these flags should only affect the 33 * top-level framework. custom flags for dealing with hardware specifics 34 * belong in struct clk_foo 35 */ 36#define CLK_SET_RATE_GATE BIT(0) /* must be gated across rate change */ 37#define CLK_SET_PARENT_GATE BIT(1) /* must be gated across re-parent */ 38#define CLK_SET_RATE_PARENT BIT(2) /* propagate rate change up one level */ 39#define CLK_IGNORE_UNUSED BIT(3) /* do not gate even if unused */ 40#define CLK_IS_ROOT BIT(4) /* root clk, has no parent */ 41 42/** 43 * struct clk_ops - Callback operations for hardware clocks; these are to 44 * be provided by the clock implementation, and will be called by drivers 45 * through the clk_* api. 46 * 47 * @prepare: Prepare the clock for enabling. This must not return until 48 * the clock is fully prepared, and it's safe to call clk_enable. 49 * This callback is intended to allow clock implementations to 50 * do any initialisation that may sleep. Called with 51 * prepare_lock held. 52 * 53 * @unprepare: Release the clock from its prepared state. This will typically 54 * undo any work done in the @prepare callback. Called with 55 * prepare_lock held. 56 * 57 * @enable: Enable the clock atomically. This must not return until the 58 * clock is generating a valid clock signal, usable by consumer 59 * devices. Called with enable_lock held. This function must not 60 * sleep. 61 * 62 * @disable: Disable the clock atomically. Called with enable_lock held. 63 * This function must not sleep. 64 * 65 * @recalc_rate Recalculate the rate of this clock, by quering hardware. The 66 * parent rate is an input parameter. It is up to the caller to 67 * insure that the prepare_mutex is held across this call. 68 * Returns the calculated rate. Optional, but recommended - if 69 * this op is not set then clock rate will be initialized to 0. 70 * 71 * @round_rate: Given a target rate as input, returns the closest rate actually 72 * supported by the clock. 73 * 74 * @get_parent: Queries the hardware to determine the parent of a clock. The 75 * return value is a u8 which specifies the index corresponding to 76 * the parent clock. This index can be applied to either the 77 * .parent_names or .parents arrays. In short, this function 78 * translates the parent value read from hardware into an array 79 * index. Currently only called when the clock is initialized by 80 * __clk_init. This callback is mandatory for clocks with 81 * multiple parents. It is optional (and unnecessary) for clocks 82 * with 0 or 1 parents. 83 * 84 * @set_parent: Change the input source of this clock; for clocks with multiple 85 * possible parents specify a new parent by passing in the index 86 * as a u8 corresponding to the parent in either the .parent_names 87 * or .parents arrays. This function in affect translates an 88 * array index into the value programmed into the hardware. 89 * Returns 0 on success, -EERROR otherwise. 90 * 91 * @set_rate: Change the rate of this clock. The requested rate is specified 92 * by the second argument, which should typically be the return 93 * of .round_rate call. The third argument gives the parent rate 94 * which is likely helpful for most .set_rate implementation. 95 * Returns 0 on success, -EERROR otherwise. 96 * 97 * The clk_enable/clk_disable and clk_prepare/clk_unprepare pairs allow 98 * implementations to split any work between atomic (enable) and sleepable 99 * (prepare) contexts. If enabling a clock requires code that might sleep, 100 * this must be done in clk_prepare. Clock enable code that will never be 101 * called in a sleepable context may be implement in clk_enable. 102 * 103 * Typically, drivers will call clk_prepare when a clock may be needed later 104 * (eg. when a device is opened), and clk_enable when the clock is actually 105 * required (eg. from an interrupt). Note that clk_prepare MUST have been 106 * called before clk_enable. 107 */ 108struct clk_ops { 109 int (*prepare)(struct clk_hw *hw); 110 void (*unprepare)(struct clk_hw *hw); 111 int (*enable)(struct clk_hw *hw); 112 void (*disable)(struct clk_hw *hw); 113 int (*is_enabled)(struct clk_hw *hw); 114 unsigned long (*recalc_rate)(struct clk_hw *hw, 115 unsigned long parent_rate); 116 long (*round_rate)(struct clk_hw *hw, unsigned long, 117 unsigned long *); 118 int (*set_parent)(struct clk_hw *hw, u8 index); 119 u8 (*get_parent)(struct clk_hw *hw); 120 int (*set_rate)(struct clk_hw *hw, unsigned long, 121 unsigned long); 122 void (*init)(struct clk_hw *hw); 123}; 124 125/* 126 * DOC: Basic clock implementations common to many platforms 127 * 128 * Each basic clock hardware type is comprised of a structure describing the 129 * clock hardware, implementations of the relevant callbacks in struct clk_ops, 130 * unique flags for that hardware type, a registration function and an 131 * alternative macro for static initialization 132 */ 133 134/** 135 * struct clk_fixed_rate - fixed-rate clock 136 * @hw: handle between common and hardware-specific interfaces 137 * @fixed_rate: constant frequency of clock 138 */ 139struct clk_fixed_rate { 140 struct clk_hw hw; 141 unsigned long fixed_rate; 142 u8 flags; 143}; 144 145extern const struct clk_ops clk_fixed_rate_ops; 146struct clk *clk_register_fixed_rate(struct device *dev, const char *name, 147 const char *parent_name, unsigned long flags, 148 unsigned long fixed_rate); 149 150/** 151 * struct clk_gate - gating clock 152 * 153 * @hw: handle between common and hardware-specific interfaces 154 * @reg: register controlling gate 155 * @bit_idx: single bit controlling gate 156 * @flags: hardware-specific flags 157 * @lock: register lock 158 * 159 * Clock which can gate its output. Implements .enable & .disable 160 * 161 * Flags: 162 * CLK_GATE_SET_DISABLE - by default this clock sets the bit at bit_idx to 163 * enable the clock. Setting this flag does the opposite: setting the bit 164 * disable the clock and clearing it enables the clock 165 */ 166struct clk_gate { 167 struct clk_hw hw; 168 void __iomem *reg; 169 u8 bit_idx; 170 u8 flags; 171 spinlock_t *lock; 172}; 173 174#define CLK_GATE_SET_TO_DISABLE BIT(0) 175 176extern const struct clk_ops clk_gate_ops; 177struct clk *clk_register_gate(struct device *dev, const char *name, 178 const char *parent_name, unsigned long flags, 179 void __iomem *reg, u8 bit_idx, 180 u8 clk_gate_flags, spinlock_t *lock); 181 182/** 183 * struct clk_divider - adjustable divider clock 184 * 185 * @hw: handle between common and hardware-specific interfaces 186 * @reg: register containing the divider 187 * @shift: shift to the divider bit field 188 * @width: width of the divider bit field 189 * @lock: register lock 190 * 191 * Clock with an adjustable divider affecting its output frequency. Implements 192 * .recalc_rate, .set_rate and .round_rate 193 * 194 * Flags: 195 * CLK_DIVIDER_ONE_BASED - by default the divisor is the value read from the 196 * register plus one. If CLK_DIVIDER_ONE_BASED is set then the divider is 197 * the raw value read from the register, with the value of zero considered 198 * invalid 199 * CLK_DIVIDER_POWER_OF_TWO - clock divisor is 2 raised to the value read from 200 * the hardware register 201 */ 202struct clk_divider { 203 struct clk_hw hw; 204 void __iomem *reg; 205 u8 shift; 206 u8 width; 207 u8 flags; 208 spinlock_t *lock; 209}; 210 211#define CLK_DIVIDER_ONE_BASED BIT(0) 212#define CLK_DIVIDER_POWER_OF_TWO BIT(1) 213 214extern const struct clk_ops clk_divider_ops; 215struct clk *clk_register_divider(struct device *dev, const char *name, 216 const char *parent_name, unsigned long flags, 217 void __iomem *reg, u8 shift, u8 width, 218 u8 clk_divider_flags, spinlock_t *lock); 219 220/** 221 * struct clk_mux - multiplexer clock 222 * 223 * @hw: handle between common and hardware-specific interfaces 224 * @reg: register controlling multiplexer 225 * @shift: shift to multiplexer bit field 226 * @width: width of mutliplexer bit field 227 * @num_clks: number of parent clocks 228 * @lock: register lock 229 * 230 * Clock with multiple selectable parents. Implements .get_parent, .set_parent 231 * and .recalc_rate 232 * 233 * Flags: 234 * CLK_MUX_INDEX_ONE - register index starts at 1, not 0 235 * CLK_MUX_INDEX_BITWISE - register index is a single bit (power of two) 236 */ 237struct clk_mux { 238 struct clk_hw hw; 239 void __iomem *reg; 240 u8 shift; 241 u8 width; 242 u8 flags; 243 spinlock_t *lock; 244}; 245 246#define CLK_MUX_INDEX_ONE BIT(0) 247#define CLK_MUX_INDEX_BIT BIT(1) 248 249extern const struct clk_ops clk_mux_ops; 250struct clk *clk_register_mux(struct device *dev, const char *name, 251 const char **parent_names, u8 num_parents, unsigned long flags, 252 void __iomem *reg, u8 shift, u8 width, 253 u8 clk_mux_flags, spinlock_t *lock); 254 255/** 256 * clk_register - allocate a new clock, register it and return an opaque cookie 257 * @dev: device that is registering this clock 258 * @name: clock name 259 * @ops: operations this clock supports 260 * @hw: link to hardware-specific clock data 261 * @parent_names: array of string names for all possible parents 262 * @num_parents: number of possible parents 263 * @flags: framework-level hints and quirks 264 * 265 * clk_register is the primary interface for populating the clock tree with new 266 * clock nodes. It returns a pointer to the newly allocated struct clk which 267 * cannot be dereferenced by driver code but may be used in conjuction with the 268 * rest of the clock API. In the event of an error clk_register will return an 269 * error code; drivers must test for an error code after calling clk_register. 270 */ 271struct clk *clk_register(struct device *dev, const char *name, 272 const struct clk_ops *ops, struct clk_hw *hw, 273 const char **parent_names, u8 num_parents, unsigned long flags); 274 275/* helper functions */ 276const char *__clk_get_name(struct clk *clk); 277struct clk_hw *__clk_get_hw(struct clk *clk); 278u8 __clk_get_num_parents(struct clk *clk); 279struct clk *__clk_get_parent(struct clk *clk); 280inline int __clk_get_enable_count(struct clk *clk); 281inline int __clk_get_prepare_count(struct clk *clk); 282unsigned long __clk_get_rate(struct clk *clk); 283unsigned long __clk_get_flags(struct clk *clk); 284int __clk_is_enabled(struct clk *clk); 285struct clk *__clk_lookup(const char *name); 286 287/* 288 * FIXME clock api without lock protection 289 */ 290int __clk_prepare(struct clk *clk); 291void __clk_unprepare(struct clk *clk); 292void __clk_reparent(struct clk *clk, struct clk *new_parent); 293unsigned long __clk_round_rate(struct clk *clk, unsigned long rate); 294 295#endif /* CONFIG_COMMON_CLK */ 296#endif /* CLK_PROVIDER_H */ 297