xref: /openbmc/linux/drivers/pwm/pwm-sti.c (revision 04dc82e1)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * PWM device driver for ST SoCs
4  *
5  * Copyright (C) 2013-2016 STMicroelectronics (R&D) Limited
6  *
7  * Author: Ajit Pal Singh <ajitpal.singh@st.com>
8  *         Lee Jones <lee.jones@linaro.org>
9  */
10 
11 #include <linux/clk.h>
12 #include <linux/interrupt.h>
13 #include <linux/math64.h>
14 #include <linux/mfd/syscon.h>
15 #include <linux/module.h>
16 #include <linux/of.h>
17 #include <linux/platform_device.h>
18 #include <linux/pwm.h>
19 #include <linux/regmap.h>
20 #include <linux/sched.h>
21 #include <linux/slab.h>
22 #include <linux/time.h>
23 #include <linux/wait.h>
24 
25 #define PWM_OUT_VAL(x)	(0x00 + (4 * (x))) /* Device's Duty Cycle register */
26 #define PWM_CPT_VAL(x)	(0x10 + (4 * (x))) /* Capture value */
27 #define PWM_CPT_EDGE(x) (0x30 + (4 * (x))) /* Edge to capture on */
28 
29 #define STI_PWM_CTRL		0x50	/* Control/Config register */
30 #define STI_INT_EN		0x54	/* Interrupt Enable/Disable register */
31 #define STI_INT_STA		0x58	/* Interrupt Status register */
32 #define PWM_INT_ACK		0x5c
33 #define PWM_PRESCALE_LOW_MASK	0x0f
34 #define PWM_PRESCALE_HIGH_MASK	0xf0
35 #define PWM_CPT_EDGE_MASK	0x03
36 #define PWM_INT_ACK_MASK	0x1ff
37 
38 #define STI_MAX_CPT_DEVS	4
39 #define CPT_DC_MAX		0xff
40 
41 /* Regfield IDs */
42 enum {
43 	/* Bits in PWM_CTRL*/
44 	PWMCLK_PRESCALE_LOW,
45 	PWMCLK_PRESCALE_HIGH,
46 	CPTCLK_PRESCALE,
47 
48 	PWM_OUT_EN,
49 	PWM_CPT_EN,
50 
51 	PWM_CPT_INT_EN,
52 	PWM_CPT_INT_STAT,
53 
54 	/* Keep last */
55 	MAX_REGFIELDS
56 };
57 
58 /*
59  * Each capture input can be programmed to detect rising-edge, falling-edge,
60  * either edge or neither egde.
61  */
62 enum sti_cpt_edge {
63 	CPT_EDGE_DISABLED,
64 	CPT_EDGE_RISING,
65 	CPT_EDGE_FALLING,
66 	CPT_EDGE_BOTH,
67 };
68 
69 struct sti_cpt_ddata {
70 	u32 snapshot[3];
71 	unsigned int index;
72 	struct mutex lock;
73 	wait_queue_head_t wait;
74 };
75 
76 struct sti_pwm_compat_data {
77 	const struct reg_field *reg_fields;
78 	unsigned int pwm_num_devs;
79 	unsigned int cpt_num_devs;
80 	unsigned int max_pwm_cnt;
81 	unsigned int max_prescale;
82 };
83 
84 struct sti_pwm_chip {
85 	struct device *dev;
86 	struct clk *pwm_clk;
87 	struct clk *cpt_clk;
88 	struct regmap *regmap;
89 	struct sti_pwm_compat_data *cdata;
90 	struct regmap_field *prescale_low;
91 	struct regmap_field *prescale_high;
92 	struct regmap_field *pwm_out_en;
93 	struct regmap_field *pwm_cpt_en;
94 	struct regmap_field *pwm_cpt_int_en;
95 	struct regmap_field *pwm_cpt_int_stat;
96 	struct pwm_chip chip;
97 	struct pwm_device *cur;
98 	unsigned long configured;
99 	unsigned int en_count;
100 	struct mutex sti_pwm_lock; /* To sync between enable/disable calls */
101 	void __iomem *mmio;
102 };
103 
104 static const struct reg_field sti_pwm_regfields[MAX_REGFIELDS] = {
105 	[PWMCLK_PRESCALE_LOW] = REG_FIELD(STI_PWM_CTRL, 0, 3),
106 	[PWMCLK_PRESCALE_HIGH] = REG_FIELD(STI_PWM_CTRL, 11, 14),
107 	[CPTCLK_PRESCALE] = REG_FIELD(STI_PWM_CTRL, 4, 8),
108 	[PWM_OUT_EN] = REG_FIELD(STI_PWM_CTRL, 9, 9),
109 	[PWM_CPT_EN] = REG_FIELD(STI_PWM_CTRL, 10, 10),
110 	[PWM_CPT_INT_EN] = REG_FIELD(STI_INT_EN, 1, 4),
111 	[PWM_CPT_INT_STAT] = REG_FIELD(STI_INT_STA, 1, 4),
112 };
113 
114 static inline struct sti_pwm_chip *to_sti_pwmchip(struct pwm_chip *chip)
115 {
116 	return container_of(chip, struct sti_pwm_chip, chip);
117 }
118 
119 /*
120  * Calculate the prescaler value corresponding to the period.
121  */
122 static int sti_pwm_get_prescale(struct sti_pwm_chip *pc, unsigned long period,
123 				unsigned int *prescale)
124 {
125 	struct sti_pwm_compat_data *cdata = pc->cdata;
126 	unsigned long clk_rate;
127 	unsigned long value;
128 	unsigned int ps;
129 
130 	clk_rate = clk_get_rate(pc->pwm_clk);
131 	if (!clk_rate) {
132 		dev_err(pc->dev, "failed to get clock rate\n");
133 		return -EINVAL;
134 	}
135 
136 	/*
137 	 * prescale = ((period_ns * clk_rate) / (10^9 * (max_pwm_cnt + 1)) - 1
138 	 */
139 	value = NSEC_PER_SEC / clk_rate;
140 	value *= cdata->max_pwm_cnt + 1;
141 
142 	if (period % value)
143 		return -EINVAL;
144 
145 	ps  = period / value - 1;
146 	if (ps > cdata->max_prescale)
147 		return -EINVAL;
148 
149 	*prescale = ps;
150 
151 	return 0;
152 }
153 
154 /*
155  * For STiH4xx PWM IP, the PWM period is fixed to 256 local clock cycles. The
156  * only way to change the period (apart from changing the PWM input clock) is
157  * to change the PWM clock prescaler.
158  *
159  * The prescaler is of 8 bits, so 256 prescaler values and hence 256 possible
160  * period values are supported (for a particular clock rate). The requested
161  * period will be applied only if it matches one of these 256 values.
162  */
163 static int sti_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
164 			  int duty_ns, int period_ns)
165 {
166 	struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
167 	struct sti_pwm_compat_data *cdata = pc->cdata;
168 	unsigned int ncfg, value, prescale = 0;
169 	struct pwm_device *cur = pc->cur;
170 	struct device *dev = pc->dev;
171 	bool period_same = false;
172 	int ret;
173 
174 	ncfg = hweight_long(pc->configured);
175 	if (ncfg)
176 		period_same = (period_ns == pwm_get_period(cur));
177 
178 	/*
179 	 * Allow configuration changes if one of the following conditions
180 	 * satisfy.
181 	 * 1. No devices have been configured.
182 	 * 2. Only one device has been configured and the new request is for
183 	 *    the same device.
184 	 * 3. Only one device has been configured and the new request is for
185 	 *    a new device and period of the new device is same as the current
186 	 *    configured period.
187 	 * 4. More than one devices are configured and period of the new
188 	 *    requestis the same as the current period.
189 	 */
190 	if (!ncfg ||
191 	    ((ncfg == 1) && (pwm->hwpwm == cur->hwpwm)) ||
192 	    ((ncfg == 1) && (pwm->hwpwm != cur->hwpwm) && period_same) ||
193 	    ((ncfg > 1) && period_same)) {
194 		/* Enable clock before writing to PWM registers. */
195 		ret = clk_enable(pc->pwm_clk);
196 		if (ret)
197 			return ret;
198 
199 		ret = clk_enable(pc->cpt_clk);
200 		if (ret)
201 			return ret;
202 
203 		if (!period_same) {
204 			ret = sti_pwm_get_prescale(pc, period_ns, &prescale);
205 			if (ret)
206 				goto clk_dis;
207 
208 			value = prescale & PWM_PRESCALE_LOW_MASK;
209 
210 			ret = regmap_field_write(pc->prescale_low, value);
211 			if (ret)
212 				goto clk_dis;
213 
214 			value = (prescale & PWM_PRESCALE_HIGH_MASK) >> 4;
215 
216 			ret = regmap_field_write(pc->prescale_high, value);
217 			if (ret)
218 				goto clk_dis;
219 		}
220 
221 		/*
222 		 * When PWMVal == 0, PWM pulse = 1 local clock cycle.
223 		 * When PWMVal == max_pwm_count,
224 		 * PWM pulse = (max_pwm_count + 1) local cycles,
225 		 * that is continuous pulse: signal never goes low.
226 		 */
227 		value = cdata->max_pwm_cnt * duty_ns / period_ns;
228 
229 		ret = regmap_write(pc->regmap, PWM_OUT_VAL(pwm->hwpwm), value);
230 		if (ret)
231 			goto clk_dis;
232 
233 		ret = regmap_field_write(pc->pwm_cpt_int_en, 0);
234 
235 		set_bit(pwm->hwpwm, &pc->configured);
236 		pc->cur = pwm;
237 
238 		dev_dbg(dev, "prescale:%u, period:%i, duty:%i, value:%u\n",
239 			prescale, period_ns, duty_ns, value);
240 	} else {
241 		return -EINVAL;
242 	}
243 
244 clk_dis:
245 	clk_disable(pc->pwm_clk);
246 	clk_disable(pc->cpt_clk);
247 	return ret;
248 }
249 
250 static int sti_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
251 {
252 	struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
253 	struct device *dev = pc->dev;
254 	int ret = 0;
255 
256 	/*
257 	 * Since we have a common enable for all PWM devices, do not enable if
258 	 * already enabled.
259 	 */
260 	mutex_lock(&pc->sti_pwm_lock);
261 
262 	if (!pc->en_count) {
263 		ret = clk_enable(pc->pwm_clk);
264 		if (ret)
265 			goto out;
266 
267 		ret = clk_enable(pc->cpt_clk);
268 		if (ret)
269 			goto out;
270 
271 		ret = regmap_field_write(pc->pwm_out_en, 1);
272 		if (ret) {
273 			dev_err(dev, "failed to enable PWM device %u: %d\n",
274 				pwm->hwpwm, ret);
275 			goto out;
276 		}
277 	}
278 
279 	pc->en_count++;
280 
281 out:
282 	mutex_unlock(&pc->sti_pwm_lock);
283 	return ret;
284 }
285 
286 static void sti_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
287 {
288 	struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
289 
290 	mutex_lock(&pc->sti_pwm_lock);
291 
292 	if (--pc->en_count) {
293 		mutex_unlock(&pc->sti_pwm_lock);
294 		return;
295 	}
296 
297 	regmap_field_write(pc->pwm_out_en, 0);
298 
299 	clk_disable(pc->pwm_clk);
300 	clk_disable(pc->cpt_clk);
301 
302 	mutex_unlock(&pc->sti_pwm_lock);
303 }
304 
305 static void sti_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
306 {
307 	struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
308 
309 	clear_bit(pwm->hwpwm, &pc->configured);
310 }
311 
312 static int sti_pwm_capture(struct pwm_chip *chip, struct pwm_device *pwm,
313 			   struct pwm_capture *result, unsigned long timeout)
314 {
315 	struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
316 	struct sti_pwm_compat_data *cdata = pc->cdata;
317 	struct sti_cpt_ddata *ddata = pwm_get_chip_data(pwm);
318 	struct device *dev = pc->dev;
319 	unsigned int effective_ticks;
320 	unsigned long long high, low;
321 	int ret;
322 
323 	if (pwm->hwpwm >= cdata->cpt_num_devs) {
324 		dev_err(dev, "device %u is not valid\n", pwm->hwpwm);
325 		return -EINVAL;
326 	}
327 
328 	mutex_lock(&ddata->lock);
329 	ddata->index = 0;
330 
331 	/* Prepare capture measurement */
332 	regmap_write(pc->regmap, PWM_CPT_EDGE(pwm->hwpwm), CPT_EDGE_RISING);
333 	regmap_field_write(pc->pwm_cpt_int_en, BIT(pwm->hwpwm));
334 
335 	/* Enable capture */
336 	ret = regmap_field_write(pc->pwm_cpt_en, 1);
337 	if (ret) {
338 		dev_err(dev, "failed to enable PWM capture %u: %d\n",
339 			pwm->hwpwm, ret);
340 		goto out;
341 	}
342 
343 	ret = wait_event_interruptible_timeout(ddata->wait, ddata->index > 1,
344 					       msecs_to_jiffies(timeout));
345 
346 	regmap_write(pc->regmap, PWM_CPT_EDGE(pwm->hwpwm), CPT_EDGE_DISABLED);
347 
348 	if (ret == -ERESTARTSYS)
349 		goto out;
350 
351 	switch (ddata->index) {
352 	case 0:
353 	case 1:
354 		/*
355 		 * Getting here could mean:
356 		 *  - input signal is constant of less than 1 Hz
357 		 *  - there is no input signal at all
358 		 *
359 		 * In such case the frequency is rounded down to 0
360 		 */
361 		result->period = 0;
362 		result->duty_cycle = 0;
363 
364 		break;
365 
366 	case 2:
367 		/* We have everying we need */
368 		high = ddata->snapshot[1] - ddata->snapshot[0];
369 		low = ddata->snapshot[2] - ddata->snapshot[1];
370 
371 		effective_ticks = clk_get_rate(pc->cpt_clk);
372 
373 		result->period = (high + low) * NSEC_PER_SEC;
374 		result->period /= effective_ticks;
375 
376 		result->duty_cycle = high * NSEC_PER_SEC;
377 		result->duty_cycle /= effective_ticks;
378 
379 		break;
380 
381 	default:
382 		dev_err(dev, "internal error\n");
383 		break;
384 	}
385 
386 out:
387 	/* Disable capture */
388 	regmap_field_write(pc->pwm_cpt_en, 0);
389 
390 	mutex_unlock(&ddata->lock);
391 	return ret;
392 }
393 
394 static const struct pwm_ops sti_pwm_ops = {
395 	.capture = sti_pwm_capture,
396 	.config = sti_pwm_config,
397 	.enable = sti_pwm_enable,
398 	.disable = sti_pwm_disable,
399 	.free = sti_pwm_free,
400 	.owner = THIS_MODULE,
401 };
402 
403 static irqreturn_t sti_pwm_interrupt(int irq, void *data)
404 {
405 	struct sti_pwm_chip *pc = data;
406 	struct device *dev = pc->dev;
407 	struct sti_cpt_ddata *ddata;
408 	int devicenum;
409 	unsigned int cpt_int_stat;
410 	unsigned int reg;
411 	int ret = IRQ_NONE;
412 
413 	ret = regmap_field_read(pc->pwm_cpt_int_stat, &cpt_int_stat);
414 	if (ret)
415 		return ret;
416 
417 	while (cpt_int_stat) {
418 		devicenum = ffs(cpt_int_stat) - 1;
419 
420 		ddata = pwm_get_chip_data(&pc->chip.pwms[devicenum]);
421 
422 		/*
423 		 * Capture input:
424 		 *    _______                   _______
425 		 *   |       |                 |       |
426 		 * __|       |_________________|       |________
427 		 *   ^0      ^1                ^2
428 		 *
429 		 * Capture start by the first available rising edge. When a
430 		 * capture event occurs, capture value (CPT_VALx) is stored,
431 		 * index incremented, capture edge changed.
432 		 *
433 		 * After the capture, if the index > 1, we have collected the
434 		 * necessary data so we signal the thread waiting for it and
435 		 * disable the capture by setting capture edge to none
436 		 */
437 
438 		regmap_read(pc->regmap,
439 			    PWM_CPT_VAL(devicenum),
440 			    &ddata->snapshot[ddata->index]);
441 
442 		switch (ddata->index) {
443 		case 0:
444 		case 1:
445 			regmap_read(pc->regmap, PWM_CPT_EDGE(devicenum), &reg);
446 			reg ^= PWM_CPT_EDGE_MASK;
447 			regmap_write(pc->regmap, PWM_CPT_EDGE(devicenum), reg);
448 
449 			ddata->index++;
450 			break;
451 
452 		case 2:
453 			regmap_write(pc->regmap,
454 				     PWM_CPT_EDGE(devicenum),
455 				     CPT_EDGE_DISABLED);
456 			wake_up(&ddata->wait);
457 			break;
458 
459 		default:
460 			dev_err(dev, "Internal error\n");
461 		}
462 
463 		cpt_int_stat &= ~BIT_MASK(devicenum);
464 
465 		ret = IRQ_HANDLED;
466 	}
467 
468 	/* Just ACK everything */
469 	regmap_write(pc->regmap, PWM_INT_ACK, PWM_INT_ACK_MASK);
470 
471 	return ret;
472 }
473 
474 static int sti_pwm_probe_dt(struct sti_pwm_chip *pc)
475 {
476 	struct device *dev = pc->dev;
477 	const struct reg_field *reg_fields;
478 	struct device_node *np = dev->of_node;
479 	struct sti_pwm_compat_data *cdata = pc->cdata;
480 	u32 num_devs;
481 	int ret;
482 
483 	ret = of_property_read_u32(np, "st,pwm-num-chan", &num_devs);
484 	if (!ret)
485 		cdata->pwm_num_devs = num_devs;
486 
487 	ret = of_property_read_u32(np, "st,capture-num-chan", &num_devs);
488 	if (!ret)
489 		cdata->cpt_num_devs = num_devs;
490 
491 	if (!cdata->pwm_num_devs && !cdata->cpt_num_devs) {
492 		dev_err(dev, "No channels configured\n");
493 		return -EINVAL;
494 	}
495 
496 	reg_fields = cdata->reg_fields;
497 
498 	pc->prescale_low = devm_regmap_field_alloc(dev, pc->regmap,
499 					reg_fields[PWMCLK_PRESCALE_LOW]);
500 	if (IS_ERR(pc->prescale_low))
501 		return PTR_ERR(pc->prescale_low);
502 
503 	pc->prescale_high = devm_regmap_field_alloc(dev, pc->regmap,
504 					reg_fields[PWMCLK_PRESCALE_HIGH]);
505 	if (IS_ERR(pc->prescale_high))
506 		return PTR_ERR(pc->prescale_high);
507 
508 
509 	pc->pwm_out_en = devm_regmap_field_alloc(dev, pc->regmap,
510 						 reg_fields[PWM_OUT_EN]);
511 	if (IS_ERR(pc->pwm_out_en))
512 		return PTR_ERR(pc->pwm_out_en);
513 
514 	pc->pwm_cpt_en = devm_regmap_field_alloc(dev, pc->regmap,
515 						 reg_fields[PWM_CPT_EN]);
516 	if (IS_ERR(pc->pwm_cpt_en))
517 		return PTR_ERR(pc->pwm_cpt_en);
518 
519 	pc->pwm_cpt_int_en = devm_regmap_field_alloc(dev, pc->regmap,
520 						reg_fields[PWM_CPT_INT_EN]);
521 	if (IS_ERR(pc->pwm_cpt_int_en))
522 		return PTR_ERR(pc->pwm_cpt_int_en);
523 
524 	pc->pwm_cpt_int_stat = devm_regmap_field_alloc(dev, pc->regmap,
525 						reg_fields[PWM_CPT_INT_STAT]);
526 	if (PTR_ERR_OR_ZERO(pc->pwm_cpt_int_stat))
527 		return PTR_ERR(pc->pwm_cpt_int_stat);
528 
529 	return 0;
530 }
531 
532 static const struct regmap_config sti_pwm_regmap_config = {
533 	.reg_bits = 32,
534 	.val_bits = 32,
535 	.reg_stride = 4,
536 };
537 
538 static int sti_pwm_probe(struct platform_device *pdev)
539 {
540 	struct device *dev = &pdev->dev;
541 	struct sti_pwm_compat_data *cdata;
542 	struct sti_pwm_chip *pc;
543 	struct resource *res;
544 	unsigned int i;
545 	int irq, ret;
546 
547 	pc = devm_kzalloc(dev, sizeof(*pc), GFP_KERNEL);
548 	if (!pc)
549 		return -ENOMEM;
550 
551 	cdata = devm_kzalloc(dev, sizeof(*cdata), GFP_KERNEL);
552 	if (!cdata)
553 		return -ENOMEM;
554 
555 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
556 
557 	pc->mmio = devm_ioremap_resource(dev, res);
558 	if (IS_ERR(pc->mmio))
559 		return PTR_ERR(pc->mmio);
560 
561 	pc->regmap = devm_regmap_init_mmio(dev, pc->mmio,
562 					   &sti_pwm_regmap_config);
563 	if (IS_ERR(pc->regmap))
564 		return PTR_ERR(pc->regmap);
565 
566 	irq = platform_get_irq(pdev, 0);
567 	if (irq < 0) {
568 		dev_err(&pdev->dev, "Failed to obtain IRQ\n");
569 		return irq;
570 	}
571 
572 	ret = devm_request_irq(&pdev->dev, irq, sti_pwm_interrupt, 0,
573 			       pdev->name, pc);
574 	if (ret < 0) {
575 		dev_err(&pdev->dev, "Failed to request IRQ\n");
576 		return ret;
577 	}
578 
579 	/*
580 	 * Setup PWM data with default values: some values could be replaced
581 	 * with specific ones provided from Device Tree.
582 	 */
583 	cdata->reg_fields = sti_pwm_regfields;
584 	cdata->max_prescale = 0xff;
585 	cdata->max_pwm_cnt = 255;
586 	cdata->pwm_num_devs = 0;
587 	cdata->cpt_num_devs = 0;
588 
589 	pc->cdata = cdata;
590 	pc->dev = dev;
591 	pc->en_count = 0;
592 	mutex_init(&pc->sti_pwm_lock);
593 
594 	ret = sti_pwm_probe_dt(pc);
595 	if (ret)
596 		return ret;
597 
598 	if (!cdata->pwm_num_devs)
599 		goto skip_pwm;
600 
601 	pc->pwm_clk = of_clk_get_by_name(dev->of_node, "pwm");
602 	if (IS_ERR(pc->pwm_clk)) {
603 		dev_err(dev, "failed to get PWM clock\n");
604 		return PTR_ERR(pc->pwm_clk);
605 	}
606 
607 	ret = clk_prepare(pc->pwm_clk);
608 	if (ret) {
609 		dev_err(dev, "failed to prepare clock\n");
610 		return ret;
611 	}
612 
613 skip_pwm:
614 	if (!cdata->cpt_num_devs)
615 		goto skip_cpt;
616 
617 	pc->cpt_clk = of_clk_get_by_name(dev->of_node, "capture");
618 	if (IS_ERR(pc->cpt_clk)) {
619 		dev_err(dev, "failed to get PWM capture clock\n");
620 		return PTR_ERR(pc->cpt_clk);
621 	}
622 
623 	ret = clk_prepare(pc->cpt_clk);
624 	if (ret) {
625 		dev_err(dev, "failed to prepare clock\n");
626 		return ret;
627 	}
628 
629 skip_cpt:
630 	pc->chip.dev = dev;
631 	pc->chip.ops = &sti_pwm_ops;
632 	pc->chip.base = -1;
633 	pc->chip.npwm = pc->cdata->pwm_num_devs;
634 
635 	ret = pwmchip_add(&pc->chip);
636 	if (ret < 0) {
637 		clk_unprepare(pc->pwm_clk);
638 		clk_unprepare(pc->cpt_clk);
639 		return ret;
640 	}
641 
642 	for (i = 0; i < cdata->cpt_num_devs; i++) {
643 		struct sti_cpt_ddata *ddata;
644 
645 		ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
646 		if (!ddata)
647 			return -ENOMEM;
648 
649 		init_waitqueue_head(&ddata->wait);
650 		mutex_init(&ddata->lock);
651 
652 		pwm_set_chip_data(&pc->chip.pwms[i], ddata);
653 	}
654 
655 	platform_set_drvdata(pdev, pc);
656 
657 	return 0;
658 }
659 
660 static int sti_pwm_remove(struct platform_device *pdev)
661 {
662 	struct sti_pwm_chip *pc = platform_get_drvdata(pdev);
663 	unsigned int i;
664 
665 	for (i = 0; i < pc->cdata->pwm_num_devs; i++)
666 		pwm_disable(&pc->chip.pwms[i]);
667 
668 	clk_unprepare(pc->pwm_clk);
669 	clk_unprepare(pc->cpt_clk);
670 
671 	return pwmchip_remove(&pc->chip);
672 }
673 
674 static const struct of_device_id sti_pwm_of_match[] = {
675 	{ .compatible = "st,sti-pwm", },
676 	{ /* sentinel */ }
677 };
678 MODULE_DEVICE_TABLE(of, sti_pwm_of_match);
679 
680 static struct platform_driver sti_pwm_driver = {
681 	.driver = {
682 		.name = "sti-pwm",
683 		.of_match_table = sti_pwm_of_match,
684 	},
685 	.probe = sti_pwm_probe,
686 	.remove = sti_pwm_remove,
687 };
688 module_platform_driver(sti_pwm_driver);
689 
690 MODULE_AUTHOR("Ajit Pal Singh <ajitpal.singh@st.com>");
691 MODULE_DESCRIPTION("STMicroelectronics ST PWM driver");
692 MODULE_LICENSE("GPL");
693