summaryrefslogtreecommitdiffstats
path: root/drivers/pwm/pwm-stm32.c
blob: 6139512aab7b8953c708279ee9a61580d9adcbc3 (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
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
/*
 * Copyright (C) STMicroelectronics 2016
 *
 * Author: Gerald Baeza <gerald.baeza@st.com>
 *
 * License terms: GNU General Public License (GPL), version 2
 *
 * Inspired by timer-stm32.c from Maxime Coquelin
 *             pwm-atmel.c from Bo Shen
 */

#include <linux/mfd/stm32-timers.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>

#define CCMR_CHANNEL_SHIFT 8
#define CCMR_CHANNEL_MASK  0xFF
#define MAX_BREAKINPUT 2

struct stm32_pwm {
	struct pwm_chip chip;
	struct device *dev;
	struct clk *clk;
	struct regmap *regmap;
	u32 max_arr;
	bool have_complementary_output;
};

struct stm32_breakinput {
	u32 index;
	u32 level;
	u32 filter;
};

static inline struct stm32_pwm *to_stm32_pwm_dev(struct pwm_chip *chip)
{
	return container_of(chip, struct stm32_pwm, chip);
}

static u32 active_channels(struct stm32_pwm *dev)
{
	u32 ccer;

	regmap_read(dev->regmap, TIM_CCER, &ccer);

	return ccer & TIM_CCER_CCXE;
}

static int write_ccrx(struct stm32_pwm *dev, int ch, u32 value)
{
	switch (ch) {
	case 0:
		return regmap_write(dev->regmap, TIM_CCR1, value);
	case 1:
		return regmap_write(dev->regmap, TIM_CCR2, value);
	case 2:
		return regmap_write(dev->regmap, TIM_CCR3, value);
	case 3:
		return regmap_write(dev->regmap, TIM_CCR4, value);
	}
	return -EINVAL;
}

static int stm32_pwm_config(struct stm32_pwm *priv, int ch,
			    int duty_ns, int period_ns)
{
	unsigned long long prd, div, dty;
	unsigned int prescaler = 0;
	u32 ccmr, mask, shift;

	/* Period and prescaler values depends on clock rate */
	div = (unsigned long long)clk_get_rate(priv->clk) * period_ns;

	do_div(div, NSEC_PER_SEC);
	prd = div;

	while (div > priv->max_arr) {
		prescaler++;
		div = prd;
		do_div(div, prescaler + 1);
	}

	prd = div;

	if (prescaler > MAX_TIM_PSC)
		return -EINVAL;

	/*
	 * All channels share the same prescaler and counter so when two
	 * channels are active at the same time we can't change them
	 */
	if (active_channels(priv) & ~(1 << ch * 4)) {
		u32 psc, arr;

		regmap_read(priv->regmap, TIM_PSC, &psc);
		regmap_read(priv->regmap, TIM_ARR, &arr);

		if ((psc != prescaler) || (arr != prd - 1))
			return -EBUSY;
	}

	regmap_write(priv->regmap, TIM_PSC, prescaler);
	regmap_write(priv->regmap, TIM_ARR, prd - 1);
	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, TIM_CR1_ARPE);

	/* Calculate the duty cycles */
	dty = prd * duty_ns;
	do_div(dty, period_ns);

	write_ccrx(priv, ch, dty);

	/* Configure output mode */
	shift = (ch & 0x1) * CCMR_CHANNEL_SHIFT;
	ccmr = (TIM_CCMR_PE | TIM_CCMR_M1) << shift;
	mask = CCMR_CHANNEL_MASK << shift;

	if (ch < 2)
		regmap_update_bits(priv->regmap, TIM_CCMR1, mask, ccmr);
	else
		regmap_update_bits(priv->regmap, TIM_CCMR2, mask, ccmr);

	regmap_update_bits(priv->regmap, TIM_BDTR,
			   TIM_BDTR_MOE | TIM_BDTR_AOE,
			   TIM_BDTR_MOE | TIM_BDTR_AOE);

	return 0;
}

static int stm32_pwm_set_polarity(struct stm32_pwm *priv, int ch,
				  enum pwm_polarity polarity)
{
	u32 mask;

	mask = TIM_CCER_CC1P << (ch * 4);
	if (priv->have_complementary_output)
		mask |= TIM_CCER_CC1NP << (ch * 4);

	regmap_update_bits(priv->regmap, TIM_CCER, mask,
			   polarity == PWM_POLARITY_NORMAL ? 0 : mask);

	return 0;
}

static int stm32_pwm_enable(struct stm32_pwm *priv, int ch)
{
	u32 mask;
	int ret;

	ret = clk_enable(priv->clk);
	if (ret)
		return ret;

	/* Enable channel */
	mask = TIM_CCER_CC1E << (ch * 4);
	if (priv->have_complementary_output)
		mask |= TIM_CCER_CC1NE << (ch * 4);

	regmap_update_bits(priv->regmap, TIM_CCER, mask, mask);

	/* Make sure that registers are updated */
	regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);

	/* Enable controller */
	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, TIM_CR1_CEN);

	return 0;
}

static void stm32_pwm_disable(struct stm32_pwm *priv, int ch)
{
	u32 mask;

	/* Disable channel */
	mask = TIM_CCER_CC1E << (ch * 4);
	if (priv->have_complementary_output)
		mask |= TIM_CCER_CC1NE << (ch * 4);

	regmap_update_bits(priv->regmap, TIM_CCER, mask, 0);

	/* When all channels are disabled, we can disable the controller */
	if (!active_channels(priv))
		regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);

	clk_disable(priv->clk);
}

static int stm32_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
			   struct pwm_state *state)
{
	bool enabled;
	struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
	int ret;

	enabled = pwm->state.enabled;

	if (enabled && !state->enabled) {
		stm32_pwm_disable(priv, pwm->hwpwm);
		return 0;
	}

	if (state->polarity != pwm->state.polarity)
		stm32_pwm_set_polarity(priv, pwm->hwpwm, state->polarity);

	ret = stm32_pwm_config(priv, pwm->hwpwm,
			       state->duty_cycle, state->period);
	if (ret)
		return ret;

	if (!enabled && state->enabled)
		ret = stm32_pwm_enable(priv, pwm->hwpwm);

	return ret;
}

static const struct pwm_ops stm32pwm_ops = {
	.owner = THIS_MODULE,
	.apply = stm32_pwm_apply,
};

static int stm32_pwm_set_breakinput(struct stm32_pwm *priv,
				    int index, int level, int filter)
{
	u32 bke = (index == 0) ? TIM_BDTR_BKE : TIM_BDTR_BK2E;
	int shift = (index == 0) ? TIM_BDTR_BKF_SHIFT : TIM_BDTR_BK2F_SHIFT;
	u32 mask = (index == 0) ? TIM_BDTR_BKE | TIM_BDTR_BKP | TIM_BDTR_BKF
				: TIM_BDTR_BK2E | TIM_BDTR_BK2P | TIM_BDTR_BK2F;
	u32 bdtr = bke;

	/*
	 * The both bits could be set since only one will be wrote
	 * due to mask value.
	 */
	if (level)
		bdtr |= TIM_BDTR_BKP | TIM_BDTR_BK2P;

	bdtr |= (filter & TIM_BDTR_BKF_MASK) << shift;

	regmap_update_bits(priv->regmap, TIM_BDTR, mask, bdtr);

	regmap_read(priv->regmap, TIM_BDTR, &bdtr);

	return (bdtr & bke) ? 0 : -EINVAL;
}

static int stm32_pwm_apply_breakinputs(struct stm32_pwm *priv,
				       struct device_node *np)
{
	struct stm32_breakinput breakinput[MAX_BREAKINPUT];
	int nb, ret, i, array_size;

	nb = of_property_count_elems_of_size(np, "st,breakinput",
					     sizeof(struct stm32_breakinput));

	/*
	 * Because "st,breakinput" parameter is optional do not make probe
	 * failed if it doesn't exist.
	 */
	if (nb <= 0)
		return 0;

	if (nb > MAX_BREAKINPUT)
		return -EINVAL;

	array_size = nb * sizeof(struct stm32_breakinput) / sizeof(u32);
	ret = of_property_read_u32_array(np, "st,breakinput",
					 (u32 *)breakinput, array_size);
	if (ret)
		return ret;

	for (i = 0; i < nb && !ret; i++) {
		ret = stm32_pwm_set_breakinput(priv,
					       breakinput[i].index,
					       breakinput[i].level,
					       breakinput[i].filter);
	}

	return ret;
}

static void stm32_pwm_detect_complementary(struct stm32_pwm *priv)
{
	u32 ccer;

	/*
	 * If complementary bit doesn't exist writing 1 will have no
	 * effect so we can detect it.
	 */
	regmap_update_bits(priv->regmap,
			   TIM_CCER, TIM_CCER_CC1NE, TIM_CCER_CC1NE);
	regmap_read(priv->regmap, TIM_CCER, &ccer);
	regmap_update_bits(priv->regmap, TIM_CCER, TIM_CCER_CC1NE, 0);

	priv->have_complementary_output = (ccer != 0);
}

static int stm32_pwm_detect_channels(struct stm32_pwm *priv)
{
	u32 ccer;
	int npwm = 0;

	/*
	 * If channels enable bits don't exist writing 1 will have no
	 * effect so we can detect and count them.
	 */
	regmap_update_bits(priv->regmap,
			   TIM_CCER, TIM_CCER_CCXE, TIM_CCER_CCXE);
	regmap_read(priv->regmap, TIM_CCER, &ccer);
	regmap_update_bits(priv->regmap, TIM_CCER, TIM_CCER_CCXE, 0);

	if (ccer & TIM_CCER_CC1E)
		npwm++;

	if (ccer & TIM_CCER_CC2E)
		npwm++;

	if (ccer & TIM_CCER_CC3E)
		npwm++;

	if (ccer & TIM_CCER_CC4E)
		npwm++;

	return npwm;
}

static int stm32_pwm_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct device_node *np = dev->of_node;
	struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent);
	struct stm32_pwm *priv;
	int ret;

	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	priv->regmap = ddata->regmap;
	priv->clk = ddata->clk;
	priv->max_arr = ddata->max_arr;

	if (!priv->regmap || !priv->clk)
		return -EINVAL;

	ret = stm32_pwm_apply_breakinputs(priv, np);
	if (ret)
		return ret;

	stm32_pwm_detect_complementary(priv);

	priv->chip.base = -1;
	priv->chip.dev = dev;
	priv->chip.ops = &stm32pwm_ops;
	priv->chip.npwm = stm32_pwm_detect_channels(priv);

	ret = pwmchip_add(&priv->chip);
	if (ret < 0)
		return ret;

	platform_set_drvdata(pdev, priv);

	return 0;
}

static int stm32_pwm_remove(struct platform_device *pdev)
{
	struct stm32_pwm *priv = platform_get_drvdata(pdev);
	unsigned int i;

	for (i = 0; i < priv->chip.npwm; i++)
		pwm_disable(&priv->chip.pwms[i]);

	pwmchip_remove(&priv->chip);

	return 0;
}

static const struct of_device_id stm32_pwm_of_match[] = {
	{ .compatible = "st,stm32-pwm",	},
	{ /* end node */ },
};
MODULE_DEVICE_TABLE(of, stm32_pwm_of_match);

static struct platform_driver stm32_pwm_driver = {
	.probe	= stm32_pwm_probe,
	.remove	= stm32_pwm_remove,
	.driver	= {
		.name = "stm32-pwm",
		.of_match_table = stm32_pwm_of_match,
	},
};
module_platform_driver(stm32_pwm_driver);

MODULE_ALIAS("platform:stm32-pwm");
MODULE_DESCRIPTION("STMicroelectronics STM32 PWM driver");
MODULE_LICENSE("GPL v2");