clk-programmable.c revision 141c71dd2c00ca7d807138ece55a17c61085c793 
1/*
2 *  Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 */
10
11#include <linux/clk-provider.h>
12#include <linux/clkdev.h>
13#include <linux/clk/at91_pmc.h>
14#include <linux/of.h>
15#include <linux/of_address.h>
16#include <linux/io.h>
17#include <linux/wait.h>
18#include <linux/sched.h>
19
20#include "pmc.h"
21
22#define PROG_SOURCE_MAX		5
23#define PROG_ID_MAX		7
24
25#define PROG_STATUS_MASK(id)	(1 << ((id) + 8))
26#define PROG_PRES_MASK		0x7
27#define PROG_MAX_RM9200_CSS	3
28
29struct clk_programmable_layout {
30	u8 pres_shift;
31	u8 css_mask;
32	u8 have_slck_mck;
33};
34
35struct clk_programmable {
36	struct clk_hw hw;
37	struct at91_pmc *pmc;
38	u8 id;
39	const struct clk_programmable_layout *layout;
40};
41
42#define to_clk_programmable(hw) container_of(hw, struct clk_programmable, hw)
43
44static unsigned long clk_programmable_recalc_rate(struct clk_hw *hw,
45						  unsigned long parent_rate)
46{
47	u32 pres;
48	struct clk_programmable *prog = to_clk_programmable(hw);
49	struct at91_pmc *pmc = prog->pmc;
50	const struct clk_programmable_layout *layout = prog->layout;
51
52	pres = (pmc_read(pmc, AT91_PMC_PCKR(prog->id)) >> layout->pres_shift) &
53	       PROG_PRES_MASK;
54	return parent_rate >> pres;
55}
56
57static long clk_programmable_determine_rate(struct clk_hw *hw,
58					    unsigned long rate,
59					    unsigned long *best_parent_rate,
60					    struct clk **best_parent_clk)
61{
62	struct clk *parent = NULL;
63	long best_rate = -EINVAL;
64	unsigned long parent_rate;
65	unsigned long tmp_rate;
66	int shift;
67	int i;
68
69	for (i = 0; i < __clk_get_num_parents(hw->clk); i++) {
70		parent = clk_get_parent_by_index(hw->clk, i);
71		if (!parent)
72			continue;
73
74		parent_rate = __clk_get_rate(parent);
75		for (shift = 0; shift < PROG_PRES_MASK; shift++) {
76			tmp_rate = parent_rate >> shift;
77			if (tmp_rate <= rate)
78				break;
79		}
80
81		if (tmp_rate > rate)
82			continue;
83
84		if (best_rate < 0 || (rate - tmp_rate) < (rate - best_rate)) {
85			best_rate = tmp_rate;
86			*best_parent_rate = parent_rate;
87			*best_parent_clk = parent;
88		}
89
90		if (!best_rate)
91			break;
92	}
93
94	return best_rate;
95}
96
97static int clk_programmable_set_parent(struct clk_hw *hw, u8 index)
98{
99	struct clk_programmable *prog = to_clk_programmable(hw);
100	const struct clk_programmable_layout *layout = prog->layout;
101	struct at91_pmc *pmc = prog->pmc;
102	u32 tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id)) & ~layout->css_mask;
103
104	if (layout->have_slck_mck)
105		tmp &= AT91_PMC_CSSMCK_MCK;
106
107	if (index > layout->css_mask) {
108		if (index > PROG_MAX_RM9200_CSS && layout->have_slck_mck) {
109			tmp |= AT91_PMC_CSSMCK_MCK;
110			return 0;
111		} else {
112			return -EINVAL;
113		}
114	}
115
116	pmc_write(pmc, AT91_PMC_PCKR(prog->id), tmp | index);
117	return 0;
118}
119
120static u8 clk_programmable_get_parent(struct clk_hw *hw)
121{
122	u32 tmp;
123	u8 ret;
124	struct clk_programmable *prog = to_clk_programmable(hw);
125	struct at91_pmc *pmc = prog->pmc;
126	const struct clk_programmable_layout *layout = prog->layout;
127
128	tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id));
129	ret = tmp & layout->css_mask;
130	if (layout->have_slck_mck && (tmp & AT91_PMC_CSSMCK_MCK) && !ret)
131		ret = PROG_MAX_RM9200_CSS + 1;
132
133	return ret;
134}
135
136static int clk_programmable_set_rate(struct clk_hw *hw, unsigned long rate,
137				     unsigned long parent_rate)
138{
139	struct clk_programmable *prog = to_clk_programmable(hw);
140	struct at91_pmc *pmc = prog->pmc;
141	const struct clk_programmable_layout *layout = prog->layout;
142	unsigned long div = parent_rate / rate;
143	int shift = 0;
144	u32 tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id)) &
145		  ~(PROG_PRES_MASK << layout->pres_shift);
146
147	if (!div)
148		return -EINVAL;
149
150	shift = fls(div) - 1;
151
152	if (div != (1<<shift))
153		return -EINVAL;
154
155	if (shift >= PROG_PRES_MASK)
156		return -EINVAL;
157
158	pmc_write(pmc, AT91_PMC_PCKR(prog->id),
159		  tmp | (shift << layout->pres_shift));
160
161	return 0;
162}
163
164static const struct clk_ops programmable_ops = {
165	.recalc_rate = clk_programmable_recalc_rate,
166	.determine_rate = clk_programmable_determine_rate,
167	.get_parent = clk_programmable_get_parent,
168	.set_parent = clk_programmable_set_parent,
169	.set_rate = clk_programmable_set_rate,
170};
171
172static struct clk * __init
173at91_clk_register_programmable(struct at91_pmc *pmc,
174			       const char *name, const char **parent_names,
175			       u8 num_parents, u8 id,
176			       const struct clk_programmable_layout *layout)
177{
178	struct clk_programmable *prog;
179	struct clk *clk = NULL;
180	struct clk_init_data init;
181
182	if (id > PROG_ID_MAX)
183		return ERR_PTR(-EINVAL);
184
185	prog = kzalloc(sizeof(*prog), GFP_KERNEL);
186	if (!prog)
187		return ERR_PTR(-ENOMEM);
188
189	init.name = name;
190	init.ops = &programmable_ops;
191	init.parent_names = parent_names;
192	init.num_parents = num_parents;
193	init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
194
195	prog->id = id;
196	prog->layout = layout;
197	prog->hw.init = &init;
198	prog->pmc = pmc;
199
200	clk = clk_register(NULL, &prog->hw);
201	if (IS_ERR(clk))
202		kfree(prog);
203
204	return clk;
205}
206
207static const struct clk_programmable_layout at91rm9200_programmable_layout = {
208	.pres_shift = 2,
209	.css_mask = 0x3,
210	.have_slck_mck = 0,
211};
212
213static const struct clk_programmable_layout at91sam9g45_programmable_layout = {
214	.pres_shift = 2,
215	.css_mask = 0x3,
216	.have_slck_mck = 1,
217};
218
219static const struct clk_programmable_layout at91sam9x5_programmable_layout = {
220	.pres_shift = 4,
221	.css_mask = 0x7,
222	.have_slck_mck = 0,
223};
224
225static void __init
226of_at91_clk_prog_setup(struct device_node *np, struct at91_pmc *pmc,
227		       const struct clk_programmable_layout *layout)
228{
229	int num;
230	u32 id;
231	int i;
232	struct clk *clk;
233	int num_parents;
234	const char *parent_names[PROG_SOURCE_MAX];
235	const char *name;
236	struct device_node *progclknp;
237
238	num_parents = of_count_phandle_with_args(np, "clocks", "#clock-cells");
239	if (num_parents <= 0 || num_parents > PROG_SOURCE_MAX)
240		return;
241
242	for (i = 0; i < num_parents; ++i) {
243		parent_names[i] = of_clk_get_parent_name(np, i);
244		if (!parent_names[i])
245			return;
246	}
247
248	num = of_get_child_count(np);
249	if (!num || num > (PROG_ID_MAX + 1))
250		return;
251
252	for_each_child_of_node(np, progclknp) {
253		if (of_property_read_u32(progclknp, "reg", &id))
254			continue;
255
256		if (of_property_read_string(np, "clock-output-names", &name))
257			name = progclknp->name;
258
259		clk = at91_clk_register_programmable(pmc, name,
260						     parent_names, num_parents,
261						     id, layout);
262		if (IS_ERR(clk))
263			continue;
264
265		of_clk_add_provider(progclknp, of_clk_src_simple_get, clk);
266	}
267}
268
269
270void __init of_at91rm9200_clk_prog_setup(struct device_node *np,
271					 struct at91_pmc *pmc)
272{
273	of_at91_clk_prog_setup(np, pmc, &at91rm9200_programmable_layout);
274}
275
276void __init of_at91sam9g45_clk_prog_setup(struct device_node *np,
277					  struct at91_pmc *pmc)
278{
279	of_at91_clk_prog_setup(np, pmc, &at91sam9g45_programmable_layout);
280}
281
282void __init of_at91sam9x5_clk_prog_setup(struct device_node *np,
283					 struct at91_pmc *pmc)
284{
285	of_at91_clk_prog_setup(np, pmc, &at91sam9x5_programmable_layout);
286}
287