summaryrefslogtreecommitdiffstats
path: root/drivers/clk/at91/clk-generated.c
blob: 5f18847965c16bcb89c858ac22958a65761382bb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
/*
 *  Copyright (C) 2015 Atmel Corporation,
 *                     Nicolas Ferre <nicolas.ferre@atmel.com>
 *
 * Based on clk-programmable & clk-peripheral drivers by Boris BREZILLON.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 */

#include <linux/bitfield.h>
#include <linux/clk-provider.h>
#include <linux/clkdev.h>
#include <linux/clk/at91_pmc.h>
#include <linux/of.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>

#include "pmc.h"

#define GENERATED_MAX_DIV	255

#define GCK_INDEX_DT_AUDIO_PLL	5

struct clk_generated {
	struct clk_hw hw;
	struct regmap *regmap;
	struct clk_range range;
	spinlock_t *lock;
	u32 id;
	u32 gckdiv;
	const struct clk_pcr_layout *layout;
	u8 parent_id;
	bool audio_pll_allowed;
};

#define to_clk_generated(hw) \
	container_of(hw, struct clk_generated, hw)

static int clk_generated_enable(struct clk_hw *hw)
{
	struct clk_generated *gck = to_clk_generated(hw);
	unsigned long flags;

	pr_debug("GCLK: %s, gckdiv = %d, parent id = %d\n",
		 __func__, gck->gckdiv, gck->parent_id);

	spin_lock_irqsave(gck->lock, flags);
	regmap_write(gck->regmap, gck->layout->offset,
		     (gck->id & gck->layout->pid_mask));
	regmap_update_bits(gck->regmap, gck->layout->offset,
			   AT91_PMC_PCR_GCKDIV_MASK | gck->layout->gckcss_mask |
			   gck->layout->cmd | AT91_PMC_PCR_GCKEN,
			   field_prep(gck->layout->gckcss_mask, gck->parent_id) |
			   gck->layout->cmd |
			   FIELD_PREP(AT91_PMC_PCR_GCKDIV_MASK, gck->gckdiv) |
			   AT91_PMC_PCR_GCKEN);
	spin_unlock_irqrestore(gck->lock, flags);
	return 0;
}

static void clk_generated_disable(struct clk_hw *hw)
{
	struct clk_generated *gck = to_clk_generated(hw);
	unsigned long flags;

	spin_lock_irqsave(gck->lock, flags);
	regmap_write(gck->regmap, gck->layout->offset,
		     (gck->id & gck->layout->pid_mask));
	regmap_update_bits(gck->regmap, gck->layout->offset,
			   gck->layout->cmd | AT91_PMC_PCR_GCKEN,
			   gck->layout->cmd);
	spin_unlock_irqrestore(gck->lock, flags);
}

static int clk_generated_is_enabled(struct clk_hw *hw)
{
	struct clk_generated *gck = to_clk_generated(hw);
	unsigned long flags;
	unsigned int status;

	spin_lock_irqsave(gck->lock, flags);
	regmap_write(gck->regmap, gck->layout->offset,
		     (gck->id & gck->layout->pid_mask));
	regmap_read(gck->regmap, gck->layout->offset, &status);
	spin_unlock_irqrestore(gck->lock, flags);

	return status & AT91_PMC_PCR_GCKEN ? 1 : 0;
}

static unsigned long
clk_generated_recalc_rate(struct clk_hw *hw,
			  unsigned long parent_rate)
{
	struct clk_generated *gck = to_clk_generated(hw);

	return DIV_ROUND_CLOSEST(parent_rate, gck->gckdiv + 1);
}

static void clk_generated_best_diff(struct clk_rate_request *req,
				    struct clk_hw *parent,
				    unsigned long parent_rate, u32 div,
				    int *best_diff, long *best_rate)
{
	unsigned long tmp_rate;
	int tmp_diff;

	if (!div)
		tmp_rate = parent_rate;
	else
		tmp_rate = parent_rate / div;
	tmp_diff = abs(req->rate - tmp_rate);

	if (*best_diff < 0 || *best_diff > tmp_diff) {
		*best_rate = tmp_rate;
		*best_diff = tmp_diff;
		req->best_parent_rate = parent_rate;
		req->best_parent_hw = parent;
	}
}

static int clk_generated_determine_rate(struct clk_hw *hw,
					struct clk_rate_request *req)
{
	struct clk_generated *gck = to_clk_generated(hw);
	struct clk_hw *parent = NULL;
	struct clk_rate_request req_parent = *req;
	long best_rate = -EINVAL;
	unsigned long min_rate, parent_rate;
	int best_diff = -1;
	int i;
	u32 div;

	for (i = 0; i < clk_hw_get_num_parents(hw) - 1; i++) {
		parent = clk_hw_get_parent_by_index(hw, i);
		if (!parent)
			continue;

		parent_rate = clk_hw_get_rate(parent);
		min_rate = DIV_ROUND_CLOSEST(parent_rate, GENERATED_MAX_DIV + 1);
		if (!parent_rate ||
		    (gck->range.max && min_rate > gck->range.max))
			continue;

		div = DIV_ROUND_CLOSEST(parent_rate, req->rate);

		clk_generated_best_diff(req, parent, parent_rate, div,
					&best_diff, &best_rate);

		if (!best_diff)
			break;
	}

	/*
	 * The audio_pll rate can be modified, unlike the five others clocks
	 * that should never be altered.
	 * The audio_pll can technically be used by multiple consumers. However,
	 * with the rate locking, the first consumer to enable to clock will be
	 * the one definitely setting the rate of the clock.
	 * Since audio IPs are most likely to request the same rate, we enforce
	 * that the only clks able to modify gck rate are those of audio IPs.
	 */

	if (!gck->audio_pll_allowed)
		goto end;

	parent = clk_hw_get_parent_by_index(hw, GCK_INDEX_DT_AUDIO_PLL);
	if (!parent)
		goto end;

	for (div = 1; div < GENERATED_MAX_DIV + 2; div++) {
		req_parent.rate = req->rate * div;
		__clk_determine_rate(parent, &req_parent);
		clk_generated_best_diff(req, parent, req_parent.rate, div,
					&best_diff, &best_rate);

		if (!best_diff)
			break;
	}

end:
	pr_debug("GCLK: %s, best_rate = %ld, parent clk: %s @ %ld\n",
		 __func__, best_rate,
		 __clk_get_name((req->best_parent_hw)->clk),
		 req->best_parent_rate);

	if (best_rate < 0)
		return best_rate;

	req->rate = best_rate;
	return 0;
}

/* No modification of hardware as we have the flag CLK_SET_PARENT_GATE set */
static int clk_generated_set_parent(struct clk_hw *hw, u8 index)
{
	struct clk_generated *gck = to_clk_generated(hw);

	if (index >= clk_hw_get_num_parents(hw))
		return -EINVAL;

	gck->parent_id = index;
	return 0;
}

static u8 clk_generated_get_parent(struct clk_hw *hw)
{
	struct clk_generated *gck = to_clk_generated(hw);

	return gck->parent_id;
}

/* No modification of hardware as we have the flag CLK_SET_RATE_GATE set */
static int clk_generated_set_rate(struct clk_hw *hw,
				  unsigned long rate,
				  unsigned long parent_rate)
{
	struct clk_generated *gck = to_clk_generated(hw);
	u32 div;

	if (!rate)
		return -EINVAL;

	if (gck->range.max && rate > gck->range.max)
		return -EINVAL;

	div = DIV_ROUND_CLOSEST(parent_rate, rate);
	if (div > GENERATED_MAX_DIV + 1 || !div)
		return -EINVAL;

	gck->gckdiv = div - 1;
	return 0;
}

static const struct clk_ops generated_ops = {
	.enable = clk_generated_enable,
	.disable = clk_generated_disable,
	.is_enabled = clk_generated_is_enabled,
	.recalc_rate = clk_generated_recalc_rate,
	.determine_rate = clk_generated_determine_rate,
	.get_parent = clk_generated_get_parent,
	.set_parent = clk_generated_set_parent,
	.set_rate = clk_generated_set_rate,
};

/**
 * clk_generated_startup - Initialize a given clock to its default parent and
 * divisor parameter.
 *
 * @gck:	Generated clock to set the startup parameters for.
 *
 * Take parameters from the hardware and update local clock configuration
 * accordingly.
 */
static void clk_generated_startup(struct clk_generated *gck)
{
	u32 tmp;
	unsigned long flags;

	spin_lock_irqsave(gck->lock, flags);
	regmap_write(gck->regmap, gck->layout->offset,
		     (gck->id & gck->layout->pid_mask));
	regmap_read(gck->regmap, gck->layout->offset, &tmp);
	spin_unlock_irqrestore(gck->lock, flags);

	gck->parent_id = field_get(gck->layout->gckcss_mask, tmp);
	gck->gckdiv = FIELD_GET(AT91_PMC_PCR_GCKDIV_MASK, tmp);
}

struct clk_hw * __init
at91_clk_register_generated(struct regmap *regmap, spinlock_t *lock,
			    const struct clk_pcr_layout *layout,
			    const char *name, const char **parent_names,
			    u8 num_parents, u8 id, bool pll_audio,
			    const struct clk_range *range)
{
	struct clk_generated *gck;
	struct clk_init_data init;
	struct clk_hw *hw;
	int ret;

	gck = kzalloc(sizeof(*gck), GFP_KERNEL);
	if (!gck)
		return ERR_PTR(-ENOMEM);

	init.name = name;
	init.ops = &generated_ops;
	init.parent_names = parent_names;
	init.num_parents = num_parents;
	init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE |
		CLK_SET_RATE_PARENT;

	gck->id = id;
	gck->hw.init = &init;
	gck->regmap = regmap;
	gck->lock = lock;
	gck->range = *range;
	gck->audio_pll_allowed = pll_audio;
	gck->layout = layout;

	clk_generated_startup(gck);
	hw = &gck->hw;
	ret = clk_hw_register(NULL, &gck->hw);
	if (ret) {
		kfree(gck);
		hw = ERR_PTR(ret);
	} else {
		pmc_register_id(id);
	}

	return hw;
}