xref: /openbmc/linux/drivers/pwm/pwm-stm32.c (revision 0c874100)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) STMicroelectronics 2016
4  *
5  * Author: Gerald Baeza <gerald.baeza@st.com>
6  *
7  * Inspired by timer-stm32.c from Maxime Coquelin
8  *             pwm-atmel.c from Bo Shen
9  */
10 
11 #include <linux/bitfield.h>
12 #include <linux/mfd/stm32-timers.h>
13 #include <linux/module.h>
14 #include <linux/of.h>
15 #include <linux/platform_device.h>
16 #include <linux/pwm.h>
17 
18 #define CCMR_CHANNEL_SHIFT 8
19 #define CCMR_CHANNEL_MASK  0xFF
20 #define MAX_BREAKINPUT 2
21 
22 struct stm32_pwm {
23 	struct pwm_chip chip;
24 	struct mutex lock; /* protect pwm config/enable */
25 	struct clk *clk;
26 	struct regmap *regmap;
27 	u32 max_arr;
28 	bool have_complementary_output;
29 	u32 capture[4] ____cacheline_aligned; /* DMA'able buffer */
30 };
31 
32 struct stm32_breakinput {
33 	u32 index;
34 	u32 level;
35 	u32 filter;
36 };
37 
38 static inline struct stm32_pwm *to_stm32_pwm_dev(struct pwm_chip *chip)
39 {
40 	return container_of(chip, struct stm32_pwm, chip);
41 }
42 
43 static u32 active_channels(struct stm32_pwm *dev)
44 {
45 	u32 ccer;
46 
47 	regmap_read(dev->regmap, TIM_CCER, &ccer);
48 
49 	return ccer & TIM_CCER_CCXE;
50 }
51 
52 static int write_ccrx(struct stm32_pwm *dev, int ch, u32 value)
53 {
54 	switch (ch) {
55 	case 0:
56 		return regmap_write(dev->regmap, TIM_CCR1, value);
57 	case 1:
58 		return regmap_write(dev->regmap, TIM_CCR2, value);
59 	case 2:
60 		return regmap_write(dev->regmap, TIM_CCR3, value);
61 	case 3:
62 		return regmap_write(dev->regmap, TIM_CCR4, value);
63 	}
64 	return -EINVAL;
65 }
66 
67 #define TIM_CCER_CC12P (TIM_CCER_CC1P | TIM_CCER_CC2P)
68 #define TIM_CCER_CC12E (TIM_CCER_CC1E | TIM_CCER_CC2E)
69 #define TIM_CCER_CC34P (TIM_CCER_CC3P | TIM_CCER_CC4P)
70 #define TIM_CCER_CC34E (TIM_CCER_CC3E | TIM_CCER_CC4E)
71 
72 /*
73  * Capture using PWM input mode:
74  *                              ___          ___
75  * TI[1, 2, 3 or 4]: ........._|   |________|
76  *                             ^0  ^1       ^2
77  *                              .   .        .
78  *                              .   .        XXXXX
79  *                              .   .   XXXXX     |
80  *                              .  XXXXX     .    |
81  *                            XXXXX .        .    |
82  * COUNTER:        ______XXXXX  .   .        .    |_XXX
83  *                 start^       .   .        .        ^stop
84  *                      .       .   .        .
85  *                      v       v   .        v
86  *                                  v
87  * CCR1/CCR3:       tx..........t0...........t2
88  * CCR2/CCR4:       tx..............t1.........
89  *
90  * DMA burst transfer:          |            |
91  *                              v            v
92  * DMA buffer:                  { t0, tx }   { t2, t1 }
93  * DMA done:                                 ^
94  *
95  * 0: IC1/3 snapchot on rising edge: counter value -> CCR1/CCR3
96  *    + DMA transfer CCR[1/3] & CCR[2/4] values (t0, tx: doesn't care)
97  * 1: IC2/4 snapchot on falling edge: counter value -> CCR2/CCR4
98  * 2: IC1/3 snapchot on rising edge: counter value -> CCR1/CCR3
99  *    + DMA transfer CCR[1/3] & CCR[2/4] values (t2, t1)
100  *
101  * DMA done, compute:
102  * - Period     = t2 - t0
103  * - Duty cycle = t1 - t0
104  */
105 static int stm32_pwm_raw_capture(struct stm32_pwm *priv, struct pwm_device *pwm,
106 				 unsigned long tmo_ms, u32 *raw_prd,
107 				 u32 *raw_dty)
108 {
109 	struct device *parent = priv->chip.dev->parent;
110 	enum stm32_timers_dmas dma_id;
111 	u32 ccen, ccr;
112 	int ret;
113 
114 	/* Ensure registers have been updated, enable counter and capture */
115 	regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
116 	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, TIM_CR1_CEN);
117 
118 	/* Use cc1 or cc3 DMA resp for PWM input channels 1 & 2 or 3 & 4 */
119 	dma_id = pwm->hwpwm < 2 ? STM32_TIMERS_DMA_CH1 : STM32_TIMERS_DMA_CH3;
120 	ccen = pwm->hwpwm < 2 ? TIM_CCER_CC12E : TIM_CCER_CC34E;
121 	ccr = pwm->hwpwm < 2 ? TIM_CCR1 : TIM_CCR3;
122 	regmap_update_bits(priv->regmap, TIM_CCER, ccen, ccen);
123 
124 	/*
125 	 * Timer DMA burst mode. Request 2 registers, 2 bursts, to get both
126 	 * CCR1 & CCR2 (or CCR3 & CCR4) on each capture event.
127 	 * We'll get two capture snapchots: { CCR1, CCR2 }, { CCR1, CCR2 }
128 	 * or { CCR3, CCR4 }, { CCR3, CCR4 }
129 	 */
130 	ret = stm32_timers_dma_burst_read(parent, priv->capture, dma_id, ccr, 2,
131 					  2, tmo_ms);
132 	if (ret)
133 		goto stop;
134 
135 	/* Period: t2 - t0 (take care of counter overflow) */
136 	if (priv->capture[0] <= priv->capture[2])
137 		*raw_prd = priv->capture[2] - priv->capture[0];
138 	else
139 		*raw_prd = priv->max_arr - priv->capture[0] + priv->capture[2];
140 
141 	/* Duty cycle capture requires at least two capture units */
142 	if (pwm->chip->npwm < 2)
143 		*raw_dty = 0;
144 	else if (priv->capture[0] <= priv->capture[3])
145 		*raw_dty = priv->capture[3] - priv->capture[0];
146 	else
147 		*raw_dty = priv->max_arr - priv->capture[0] + priv->capture[3];
148 
149 	if (*raw_dty > *raw_prd) {
150 		/*
151 		 * Race beetween PWM input and DMA: it may happen
152 		 * falling edge triggers new capture on TI2/4 before DMA
153 		 * had a chance to read CCR2/4. It means capture[1]
154 		 * contains period + duty_cycle. So, subtract period.
155 		 */
156 		*raw_dty -= *raw_prd;
157 	}
158 
159 stop:
160 	regmap_update_bits(priv->regmap, TIM_CCER, ccen, 0);
161 	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
162 
163 	return ret;
164 }
165 
166 static int stm32_pwm_capture(struct pwm_chip *chip, struct pwm_device *pwm,
167 			     struct pwm_capture *result, unsigned long tmo_ms)
168 {
169 	struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
170 	unsigned long long prd, div, dty;
171 	unsigned long rate;
172 	unsigned int psc = 0, icpsc, scale;
173 	u32 raw_prd = 0, raw_dty = 0;
174 	int ret = 0;
175 
176 	mutex_lock(&priv->lock);
177 
178 	if (active_channels(priv)) {
179 		ret = -EBUSY;
180 		goto unlock;
181 	}
182 
183 	ret = clk_enable(priv->clk);
184 	if (ret) {
185 		dev_err(priv->chip.dev, "failed to enable counter clock\n");
186 		goto unlock;
187 	}
188 
189 	rate = clk_get_rate(priv->clk);
190 	if (!rate) {
191 		ret = -EINVAL;
192 		goto clk_dis;
193 	}
194 
195 	/* prescaler: fit timeout window provided by upper layer */
196 	div = (unsigned long long)rate * (unsigned long long)tmo_ms;
197 	do_div(div, MSEC_PER_SEC);
198 	prd = div;
199 	while ((div > priv->max_arr) && (psc < MAX_TIM_PSC)) {
200 		psc++;
201 		div = prd;
202 		do_div(div, psc + 1);
203 	}
204 	regmap_write(priv->regmap, TIM_ARR, priv->max_arr);
205 	regmap_write(priv->regmap, TIM_PSC, psc);
206 
207 	/* Map TI1 or TI2 PWM input to IC1 & IC2 (or TI3/4 to IC3 & IC4) */
208 	regmap_update_bits(priv->regmap,
209 			   pwm->hwpwm < 2 ? TIM_CCMR1 : TIM_CCMR2,
210 			   TIM_CCMR_CC1S | TIM_CCMR_CC2S, pwm->hwpwm & 0x1 ?
211 			   TIM_CCMR_CC1S_TI2 | TIM_CCMR_CC2S_TI2 :
212 			   TIM_CCMR_CC1S_TI1 | TIM_CCMR_CC2S_TI1);
213 
214 	/* Capture period on IC1/3 rising edge, duty cycle on IC2/4 falling. */
215 	regmap_update_bits(priv->regmap, TIM_CCER, pwm->hwpwm < 2 ?
216 			   TIM_CCER_CC12P : TIM_CCER_CC34P, pwm->hwpwm < 2 ?
217 			   TIM_CCER_CC2P : TIM_CCER_CC4P);
218 
219 	ret = stm32_pwm_raw_capture(priv, pwm, tmo_ms, &raw_prd, &raw_dty);
220 	if (ret)
221 		goto stop;
222 
223 	/*
224 	 * Got a capture. Try to improve accuracy at high rates:
225 	 * - decrease counter clock prescaler, scale up to max rate.
226 	 * - use input prescaler, capture once every /2 /4 or /8 edges.
227 	 */
228 	if (raw_prd) {
229 		u32 max_arr = priv->max_arr - 0x1000; /* arbitrary margin */
230 
231 		scale = max_arr / min(max_arr, raw_prd);
232 	} else {
233 		scale = priv->max_arr; /* bellow resolution, use max scale */
234 	}
235 
236 	if (psc && scale > 1) {
237 		/* 2nd measure with new scale */
238 		psc /= scale;
239 		regmap_write(priv->regmap, TIM_PSC, psc);
240 		ret = stm32_pwm_raw_capture(priv, pwm, tmo_ms, &raw_prd,
241 					    &raw_dty);
242 		if (ret)
243 			goto stop;
244 	}
245 
246 	/* Compute intermediate period not to exceed timeout at low rates */
247 	prd = (unsigned long long)raw_prd * (psc + 1) * NSEC_PER_SEC;
248 	do_div(prd, rate);
249 
250 	for (icpsc = 0; icpsc < MAX_TIM_ICPSC ; icpsc++) {
251 		/* input prescaler: also keep arbitrary margin */
252 		if (raw_prd >= (priv->max_arr - 0x1000) >> (icpsc + 1))
253 			break;
254 		if (prd >= (tmo_ms * NSEC_PER_MSEC) >> (icpsc + 2))
255 			break;
256 	}
257 
258 	if (!icpsc)
259 		goto done;
260 
261 	/* Last chance to improve period accuracy, using input prescaler */
262 	regmap_update_bits(priv->regmap,
263 			   pwm->hwpwm < 2 ? TIM_CCMR1 : TIM_CCMR2,
264 			   TIM_CCMR_IC1PSC | TIM_CCMR_IC2PSC,
265 			   FIELD_PREP(TIM_CCMR_IC1PSC, icpsc) |
266 			   FIELD_PREP(TIM_CCMR_IC2PSC, icpsc));
267 
268 	ret = stm32_pwm_raw_capture(priv, pwm, tmo_ms, &raw_prd, &raw_dty);
269 	if (ret)
270 		goto stop;
271 
272 	if (raw_dty >= (raw_prd >> icpsc)) {
273 		/*
274 		 * We may fall here using input prescaler, when input
275 		 * capture starts on high side (before falling edge).
276 		 * Example with icpsc to capture on each 4 events:
277 		 *
278 		 *       start   1st capture                     2nd capture
279 		 *         v     v                               v
280 		 *         ___   _____   _____   _____   _____   ____
281 		 * TI1..4     |__|    |__|    |__|    |__|    |__|
282 		 *            v  v    .  .    .  .    .       v  v
283 		 * icpsc1/3:  .  0    .  1    .  2    .  3    .  0
284 		 * icpsc2/4:  0       1       2       3       0
285 		 *            v  v                            v  v
286 		 * CCR1/3  ......t0..............................t2
287 		 * CCR2/4  ..t1..............................t1'...
288 		 *               .                            .  .
289 		 * Capture0:     .<----------------------------->.
290 		 * Capture1:     .<-------------------------->.  .
291 		 *               .                            .  .
292 		 * Period:       .<------>                    .  .
293 		 * Low side:                                  .<>.
294 		 *
295 		 * Result:
296 		 * - Period = Capture0 / icpsc
297 		 * - Duty = Period - Low side = Period - (Capture0 - Capture1)
298 		 */
299 		raw_dty = (raw_prd >> icpsc) - (raw_prd - raw_dty);
300 	}
301 
302 done:
303 	prd = (unsigned long long)raw_prd * (psc + 1) * NSEC_PER_SEC;
304 	result->period = DIV_ROUND_UP_ULL(prd, rate << icpsc);
305 	dty = (unsigned long long)raw_dty * (psc + 1) * NSEC_PER_SEC;
306 	result->duty_cycle = DIV_ROUND_UP_ULL(dty, rate);
307 stop:
308 	regmap_write(priv->regmap, TIM_CCER, 0);
309 	regmap_write(priv->regmap, pwm->hwpwm < 2 ? TIM_CCMR1 : TIM_CCMR2, 0);
310 	regmap_write(priv->regmap, TIM_PSC, 0);
311 clk_dis:
312 	clk_disable(priv->clk);
313 unlock:
314 	mutex_unlock(&priv->lock);
315 
316 	return ret;
317 }
318 
319 static int stm32_pwm_config(struct stm32_pwm *priv, int ch,
320 			    int duty_ns, int period_ns)
321 {
322 	unsigned long long prd, div, dty;
323 	unsigned int prescaler = 0;
324 	u32 ccmr, mask, shift;
325 
326 	/* Period and prescaler values depends on clock rate */
327 	div = (unsigned long long)clk_get_rate(priv->clk) * period_ns;
328 
329 	do_div(div, NSEC_PER_SEC);
330 	prd = div;
331 
332 	while (div > priv->max_arr) {
333 		prescaler++;
334 		div = prd;
335 		do_div(div, prescaler + 1);
336 	}
337 
338 	prd = div;
339 
340 	if (prescaler > MAX_TIM_PSC)
341 		return -EINVAL;
342 
343 	/*
344 	 * All channels share the same prescaler and counter so when two
345 	 * channels are active at the same time we can't change them
346 	 */
347 	if (active_channels(priv) & ~(1 << ch * 4)) {
348 		u32 psc, arr;
349 
350 		regmap_read(priv->regmap, TIM_PSC, &psc);
351 		regmap_read(priv->regmap, TIM_ARR, &arr);
352 
353 		if ((psc != prescaler) || (arr != prd - 1))
354 			return -EBUSY;
355 	}
356 
357 	regmap_write(priv->regmap, TIM_PSC, prescaler);
358 	regmap_write(priv->regmap, TIM_ARR, prd - 1);
359 	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, TIM_CR1_ARPE);
360 
361 	/* Calculate the duty cycles */
362 	dty = prd * duty_ns;
363 	do_div(dty, period_ns);
364 
365 	write_ccrx(priv, ch, dty);
366 
367 	/* Configure output mode */
368 	shift = (ch & 0x1) * CCMR_CHANNEL_SHIFT;
369 	ccmr = (TIM_CCMR_PE | TIM_CCMR_M1) << shift;
370 	mask = CCMR_CHANNEL_MASK << shift;
371 
372 	if (ch < 2)
373 		regmap_update_bits(priv->regmap, TIM_CCMR1, mask, ccmr);
374 	else
375 		regmap_update_bits(priv->regmap, TIM_CCMR2, mask, ccmr);
376 
377 	regmap_update_bits(priv->regmap, TIM_BDTR,
378 			   TIM_BDTR_MOE | TIM_BDTR_AOE,
379 			   TIM_BDTR_MOE | TIM_BDTR_AOE);
380 
381 	return 0;
382 }
383 
384 static int stm32_pwm_set_polarity(struct stm32_pwm *priv, int ch,
385 				  enum pwm_polarity polarity)
386 {
387 	u32 mask;
388 
389 	mask = TIM_CCER_CC1P << (ch * 4);
390 	if (priv->have_complementary_output)
391 		mask |= TIM_CCER_CC1NP << (ch * 4);
392 
393 	regmap_update_bits(priv->regmap, TIM_CCER, mask,
394 			   polarity == PWM_POLARITY_NORMAL ? 0 : mask);
395 
396 	return 0;
397 }
398 
399 static int stm32_pwm_enable(struct stm32_pwm *priv, int ch)
400 {
401 	u32 mask;
402 	int ret;
403 
404 	ret = clk_enable(priv->clk);
405 	if (ret)
406 		return ret;
407 
408 	/* Enable channel */
409 	mask = TIM_CCER_CC1E << (ch * 4);
410 	if (priv->have_complementary_output)
411 		mask |= TIM_CCER_CC1NE << (ch * 4);
412 
413 	regmap_update_bits(priv->regmap, TIM_CCER, mask, mask);
414 
415 	/* Make sure that registers are updated */
416 	regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
417 
418 	/* Enable controller */
419 	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, TIM_CR1_CEN);
420 
421 	return 0;
422 }
423 
424 static void stm32_pwm_disable(struct stm32_pwm *priv, int ch)
425 {
426 	u32 mask;
427 
428 	/* Disable channel */
429 	mask = TIM_CCER_CC1E << (ch * 4);
430 	if (priv->have_complementary_output)
431 		mask |= TIM_CCER_CC1NE << (ch * 4);
432 
433 	regmap_update_bits(priv->regmap, TIM_CCER, mask, 0);
434 
435 	/* When all channels are disabled, we can disable the controller */
436 	if (!active_channels(priv))
437 		regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
438 
439 	clk_disable(priv->clk);
440 }
441 
442 static int stm32_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
443 			   struct pwm_state *state)
444 {
445 	bool enabled;
446 	struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
447 	int ret;
448 
449 	enabled = pwm->state.enabled;
450 
451 	if (enabled && !state->enabled) {
452 		stm32_pwm_disable(priv, pwm->hwpwm);
453 		return 0;
454 	}
455 
456 	if (state->polarity != pwm->state.polarity)
457 		stm32_pwm_set_polarity(priv, pwm->hwpwm, state->polarity);
458 
459 	ret = stm32_pwm_config(priv, pwm->hwpwm,
460 			       state->duty_cycle, state->period);
461 	if (ret)
462 		return ret;
463 
464 	if (!enabled && state->enabled)
465 		ret = stm32_pwm_enable(priv, pwm->hwpwm);
466 
467 	return ret;
468 }
469 
470 static int stm32_pwm_apply_locked(struct pwm_chip *chip, struct pwm_device *pwm,
471 				  struct pwm_state *state)
472 {
473 	struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
474 	int ret;
475 
476 	/* protect common prescaler for all active channels */
477 	mutex_lock(&priv->lock);
478 	ret = stm32_pwm_apply(chip, pwm, state);
479 	mutex_unlock(&priv->lock);
480 
481 	return ret;
482 }
483 
484 static const struct pwm_ops stm32pwm_ops = {
485 	.owner = THIS_MODULE,
486 	.apply = stm32_pwm_apply_locked,
487 	.capture = IS_ENABLED(CONFIG_DMA_ENGINE) ? stm32_pwm_capture : NULL,
488 };
489 
490 static int stm32_pwm_set_breakinput(struct stm32_pwm *priv,
491 				    int index, int level, int filter)
492 {
493 	u32 bke = (index == 0) ? TIM_BDTR_BKE : TIM_BDTR_BK2E;
494 	int shift = (index == 0) ? TIM_BDTR_BKF_SHIFT : TIM_BDTR_BK2F_SHIFT;
495 	u32 mask = (index == 0) ? TIM_BDTR_BKE | TIM_BDTR_BKP | TIM_BDTR_BKF
496 				: TIM_BDTR_BK2E | TIM_BDTR_BK2P | TIM_BDTR_BK2F;
497 	u32 bdtr = bke;
498 
499 	/*
500 	 * The both bits could be set since only one will be wrote
501 	 * due to mask value.
502 	 */
503 	if (level)
504 		bdtr |= TIM_BDTR_BKP | TIM_BDTR_BK2P;
505 
506 	bdtr |= (filter & TIM_BDTR_BKF_MASK) << shift;
507 
508 	regmap_update_bits(priv->regmap, TIM_BDTR, mask, bdtr);
509 
510 	regmap_read(priv->regmap, TIM_BDTR, &bdtr);
511 
512 	return (bdtr & bke) ? 0 : -EINVAL;
513 }
514 
515 static int stm32_pwm_apply_breakinputs(struct stm32_pwm *priv,
516 				       struct device_node *np)
517 {
518 	struct stm32_breakinput breakinput[MAX_BREAKINPUT];
519 	int nb, ret, i, array_size;
520 
521 	nb = of_property_count_elems_of_size(np, "st,breakinput",
522 					     sizeof(struct stm32_breakinput));
523 
524 	/*
525 	 * Because "st,breakinput" parameter is optional do not make probe
526 	 * failed if it doesn't exist.
527 	 */
528 	if (nb <= 0)
529 		return 0;
530 
531 	if (nb > MAX_BREAKINPUT)
532 		return -EINVAL;
533 
534 	array_size = nb * sizeof(struct stm32_breakinput) / sizeof(u32);
535 	ret = of_property_read_u32_array(np, "st,breakinput",
536 					 (u32 *)breakinput, array_size);
537 	if (ret)
538 		return ret;
539 
540 	for (i = 0; i < nb && !ret; i++) {
541 		ret = stm32_pwm_set_breakinput(priv,
542 					       breakinput[i].index,
543 					       breakinput[i].level,
544 					       breakinput[i].filter);
545 	}
546 
547 	return ret;
548 }
549 
550 static void stm32_pwm_detect_complementary(struct stm32_pwm *priv)
551 {
552 	u32 ccer;
553 
554 	/*
555 	 * If complementary bit doesn't exist writing 1 will have no
556 	 * effect so we can detect it.
557 	 */
558 	regmap_update_bits(priv->regmap,
559 			   TIM_CCER, TIM_CCER_CC1NE, TIM_CCER_CC1NE);
560 	regmap_read(priv->regmap, TIM_CCER, &ccer);
561 	regmap_update_bits(priv->regmap, TIM_CCER, TIM_CCER_CC1NE, 0);
562 
563 	priv->have_complementary_output = (ccer != 0);
564 }
565 
566 static int stm32_pwm_detect_channels(struct stm32_pwm *priv)
567 {
568 	u32 ccer;
569 	int npwm = 0;
570 
571 	/*
572 	 * If channels enable bits don't exist writing 1 will have no
573 	 * effect so we can detect and count them.
574 	 */
575 	regmap_update_bits(priv->regmap,
576 			   TIM_CCER, TIM_CCER_CCXE, TIM_CCER_CCXE);
577 	regmap_read(priv->regmap, TIM_CCER, &ccer);
578 	regmap_update_bits(priv->regmap, TIM_CCER, TIM_CCER_CCXE, 0);
579 
580 	if (ccer & TIM_CCER_CC1E)
581 		npwm++;
582 
583 	if (ccer & TIM_CCER_CC2E)
584 		npwm++;
585 
586 	if (ccer & TIM_CCER_CC3E)
587 		npwm++;
588 
589 	if (ccer & TIM_CCER_CC4E)
590 		npwm++;
591 
592 	return npwm;
593 }
594 
595 static int stm32_pwm_probe(struct platform_device *pdev)
596 {
597 	struct device *dev = &pdev->dev;
598 	struct device_node *np = dev->of_node;
599 	struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent);
600 	struct stm32_pwm *priv;
601 	int ret;
602 
603 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
604 	if (!priv)
605 		return -ENOMEM;
606 
607 	mutex_init(&priv->lock);
608 	priv->regmap = ddata->regmap;
609 	priv->clk = ddata->clk;
610 	priv->max_arr = ddata->max_arr;
611 
612 	if (!priv->regmap || !priv->clk)
613 		return -EINVAL;
614 
615 	ret = stm32_pwm_apply_breakinputs(priv, np);
616 	if (ret)
617 		return ret;
618 
619 	stm32_pwm_detect_complementary(priv);
620 
621 	priv->chip.base = -1;
622 	priv->chip.dev = dev;
623 	priv->chip.ops = &stm32pwm_ops;
624 	priv->chip.npwm = stm32_pwm_detect_channels(priv);
625 
626 	ret = pwmchip_add(&priv->chip);
627 	if (ret < 0)
628 		return ret;
629 
630 	platform_set_drvdata(pdev, priv);
631 
632 	return 0;
633 }
634 
635 static int stm32_pwm_remove(struct platform_device *pdev)
636 {
637 	struct stm32_pwm *priv = platform_get_drvdata(pdev);
638 	unsigned int i;
639 
640 	for (i = 0; i < priv->chip.npwm; i++)
641 		pwm_disable(&priv->chip.pwms[i]);
642 
643 	pwmchip_remove(&priv->chip);
644 
645 	return 0;
646 }
647 
648 static const struct of_device_id stm32_pwm_of_match[] = {
649 	{ .compatible = "st,stm32-pwm",	},
650 	{ /* end node */ },
651 };
652 MODULE_DEVICE_TABLE(of, stm32_pwm_of_match);
653 
654 static struct platform_driver stm32_pwm_driver = {
655 	.probe	= stm32_pwm_probe,
656 	.remove	= stm32_pwm_remove,
657 	.driver	= {
658 		.name = "stm32-pwm",
659 		.of_match_table = stm32_pwm_of_match,
660 	},
661 };
662 module_platform_driver(stm32_pwm_driver);
663 
664 MODULE_ALIAS("platform:stm32-pwm");
665 MODULE_DESCRIPTION("STMicroelectronics STM32 PWM driver");
666 MODULE_LICENSE("GPL v2");
667