xref: /openbmc/linux/drivers/pwm/pwm-sti.c (revision b181f7029bd71238ac2754ce7052dffd69432085)
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  	struct sti_cpt_ddata *ddata;
83  };
84  
85  struct sti_pwm_chip {
86  	struct device *dev;
87  	struct clk *pwm_clk;
88  	struct clk *cpt_clk;
89  	struct regmap *regmap;
90  	struct sti_pwm_compat_data *cdata;
91  	struct regmap_field *prescale_low;
92  	struct regmap_field *prescale_high;
93  	struct regmap_field *pwm_out_en;
94  	struct regmap_field *pwm_cpt_en;
95  	struct regmap_field *pwm_cpt_int_en;
96  	struct regmap_field *pwm_cpt_int_stat;
97  	struct pwm_chip chip;
98  	struct pwm_device *cur;
99  	unsigned long configured;
100  	unsigned int en_count;
101  	struct mutex sti_pwm_lock; /* To sync between enable/disable calls */
102  	void __iomem *mmio;
103  };
104  
105  static const struct reg_field sti_pwm_regfields[MAX_REGFIELDS] = {
106  	[PWMCLK_PRESCALE_LOW] = REG_FIELD(STI_PWM_CTRL, 0, 3),
107  	[PWMCLK_PRESCALE_HIGH] = REG_FIELD(STI_PWM_CTRL, 11, 14),
108  	[CPTCLK_PRESCALE] = REG_FIELD(STI_PWM_CTRL, 4, 8),
109  	[PWM_OUT_EN] = REG_FIELD(STI_PWM_CTRL, 9, 9),
110  	[PWM_CPT_EN] = REG_FIELD(STI_PWM_CTRL, 10, 10),
111  	[PWM_CPT_INT_EN] = REG_FIELD(STI_INT_EN, 1, 4),
112  	[PWM_CPT_INT_STAT] = REG_FIELD(STI_INT_STA, 1, 4),
113  };
114  
to_sti_pwmchip(struct pwm_chip * chip)115  static inline struct sti_pwm_chip *to_sti_pwmchip(struct pwm_chip *chip)
116  {
117  	return container_of(chip, struct sti_pwm_chip, chip);
118  }
119  
120  /*
121   * Calculate the prescaler value corresponding to the period.
122   */
sti_pwm_get_prescale(struct sti_pwm_chip * pc,unsigned long period,unsigned int * prescale)123  static int sti_pwm_get_prescale(struct sti_pwm_chip *pc, unsigned long period,
124  				unsigned int *prescale)
125  {
126  	struct sti_pwm_compat_data *cdata = pc->cdata;
127  	unsigned long clk_rate;
128  	unsigned long value;
129  	unsigned int ps;
130  
131  	clk_rate = clk_get_rate(pc->pwm_clk);
132  	if (!clk_rate) {
133  		dev_err(pc->dev, "failed to get clock rate\n");
134  		return -EINVAL;
135  	}
136  
137  	/*
138  	 * prescale = ((period_ns * clk_rate) / (10^9 * (max_pwm_cnt + 1)) - 1
139  	 */
140  	value = NSEC_PER_SEC / clk_rate;
141  	value *= cdata->max_pwm_cnt + 1;
142  
143  	if (period % value)
144  		return -EINVAL;
145  
146  	ps  = period / value - 1;
147  	if (ps > cdata->max_prescale)
148  		return -EINVAL;
149  
150  	*prescale = ps;
151  
152  	return 0;
153  }
154  
155  /*
156   * For STiH4xx PWM IP, the PWM period is fixed to 256 local clock cycles. The
157   * only way to change the period (apart from changing the PWM input clock) is
158   * to change the PWM clock prescaler.
159   *
160   * The prescaler is of 8 bits, so 256 prescaler values and hence 256 possible
161   * period values are supported (for a particular clock rate). The requested
162   * period will be applied only if it matches one of these 256 values.
163   */
sti_pwm_config(struct pwm_chip * chip,struct pwm_device * pwm,int duty_ns,int period_ns)164  static int sti_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
165  			  int duty_ns, int period_ns)
166  {
167  	struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
168  	struct sti_pwm_compat_data *cdata = pc->cdata;
169  	unsigned int ncfg, value, prescale = 0;
170  	struct pwm_device *cur = pc->cur;
171  	struct device *dev = pc->dev;
172  	bool period_same = false;
173  	int ret;
174  
175  	ncfg = hweight_long(pc->configured);
176  	if (ncfg)
177  		period_same = (period_ns == pwm_get_period(cur));
178  
179  	/*
180  	 * Allow configuration changes if one of the following conditions
181  	 * satisfy.
182  	 * 1. No devices have been configured.
183  	 * 2. Only one device has been configured and the new request is for
184  	 *    the same device.
185  	 * 3. Only one device has been configured and the new request is for
186  	 *    a new device and period of the new device is same as the current
187  	 *    configured period.
188  	 * 4. More than one devices are configured and period of the new
189  	 *    requestis the same as the current period.
190  	 */
191  	if (!ncfg ||
192  	    ((ncfg == 1) && (pwm->hwpwm == cur->hwpwm)) ||
193  	    ((ncfg == 1) && (pwm->hwpwm != cur->hwpwm) && period_same) ||
194  	    ((ncfg > 1) && period_same)) {
195  		/* Enable clock before writing to PWM registers. */
196  		ret = clk_enable(pc->pwm_clk);
197  		if (ret)
198  			return ret;
199  
200  		ret = clk_enable(pc->cpt_clk);
201  		if (ret)
202  			return ret;
203  
204  		if (!period_same) {
205  			ret = sti_pwm_get_prescale(pc, period_ns, &prescale);
206  			if (ret)
207  				goto clk_dis;
208  
209  			value = prescale & PWM_PRESCALE_LOW_MASK;
210  
211  			ret = regmap_field_write(pc->prescale_low, value);
212  			if (ret)
213  				goto clk_dis;
214  
215  			value = (prescale & PWM_PRESCALE_HIGH_MASK) >> 4;
216  
217  			ret = regmap_field_write(pc->prescale_high, value);
218  			if (ret)
219  				goto clk_dis;
220  		}
221  
222  		/*
223  		 * When PWMVal == 0, PWM pulse = 1 local clock cycle.
224  		 * When PWMVal == max_pwm_count,
225  		 * PWM pulse = (max_pwm_count + 1) local cycles,
226  		 * that is continuous pulse: signal never goes low.
227  		 */
228  		value = cdata->max_pwm_cnt * duty_ns / period_ns;
229  
230  		ret = regmap_write(pc->regmap, PWM_OUT_VAL(pwm->hwpwm), value);
231  		if (ret)
232  			goto clk_dis;
233  
234  		ret = regmap_field_write(pc->pwm_cpt_int_en, 0);
235  
236  		set_bit(pwm->hwpwm, &pc->configured);
237  		pc->cur = pwm;
238  
239  		dev_dbg(dev, "prescale:%u, period:%i, duty:%i, value:%u\n",
240  			prescale, period_ns, duty_ns, value);
241  	} else {
242  		return -EINVAL;
243  	}
244  
245  clk_dis:
246  	clk_disable(pc->pwm_clk);
247  	clk_disable(pc->cpt_clk);
248  	return ret;
249  }
250  
sti_pwm_enable(struct pwm_chip * chip,struct pwm_device * pwm)251  static int sti_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
252  {
253  	struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
254  	struct device *dev = pc->dev;
255  	int ret = 0;
256  
257  	/*
258  	 * Since we have a common enable for all PWM devices, do not enable if
259  	 * already enabled.
260  	 */
261  	mutex_lock(&pc->sti_pwm_lock);
262  
263  	if (!pc->en_count) {
264  		ret = clk_enable(pc->pwm_clk);
265  		if (ret)
266  			goto out;
267  
268  		ret = clk_enable(pc->cpt_clk);
269  		if (ret)
270  			goto out;
271  
272  		ret = regmap_field_write(pc->pwm_out_en, 1);
273  		if (ret) {
274  			dev_err(dev, "failed to enable PWM device %u: %d\n",
275  				pwm->hwpwm, ret);
276  			goto out;
277  		}
278  	}
279  
280  	pc->en_count++;
281  
282  out:
283  	mutex_unlock(&pc->sti_pwm_lock);
284  	return ret;
285  }
286  
sti_pwm_disable(struct pwm_chip * chip,struct pwm_device * pwm)287  static void sti_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
288  {
289  	struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
290  
291  	mutex_lock(&pc->sti_pwm_lock);
292  
293  	if (--pc->en_count) {
294  		mutex_unlock(&pc->sti_pwm_lock);
295  		return;
296  	}
297  
298  	regmap_field_write(pc->pwm_out_en, 0);
299  
300  	clk_disable(pc->pwm_clk);
301  	clk_disable(pc->cpt_clk);
302  
303  	mutex_unlock(&pc->sti_pwm_lock);
304  }
305  
sti_pwm_free(struct pwm_chip * chip,struct pwm_device * pwm)306  static void sti_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
307  {
308  	struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
309  
310  	clear_bit(pwm->hwpwm, &pc->configured);
311  }
312  
sti_pwm_capture(struct pwm_chip * chip,struct pwm_device * pwm,struct pwm_capture * result,unsigned long timeout)313  static int sti_pwm_capture(struct pwm_chip *chip, struct pwm_device *pwm,
314  			   struct pwm_capture *result, unsigned long timeout)
315  {
316  	struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
317  	struct sti_pwm_compat_data *cdata = pc->cdata;
318  	struct sti_cpt_ddata *ddata = &cdata->ddata[pwm->hwpwm];
319  	struct device *dev = pc->dev;
320  	unsigned int effective_ticks;
321  	unsigned long long high, low;
322  	int ret;
323  
324  	if (pwm->hwpwm >= cdata->cpt_num_devs) {
325  		dev_err(dev, "device %u is not valid\n", pwm->hwpwm);
326  		return -EINVAL;
327  	}
328  
329  	mutex_lock(&ddata->lock);
330  	ddata->index = 0;
331  
332  	/* Prepare capture measurement */
333  	regmap_write(pc->regmap, PWM_CPT_EDGE(pwm->hwpwm), CPT_EDGE_RISING);
334  	regmap_field_write(pc->pwm_cpt_int_en, BIT(pwm->hwpwm));
335  
336  	/* Enable capture */
337  	ret = regmap_field_write(pc->pwm_cpt_en, 1);
338  	if (ret) {
339  		dev_err(dev, "failed to enable PWM capture %u: %d\n",
340  			pwm->hwpwm, ret);
341  		goto out;
342  	}
343  
344  	ret = wait_event_interruptible_timeout(ddata->wait, ddata->index > 1,
345  					       msecs_to_jiffies(timeout));
346  
347  	regmap_write(pc->regmap, PWM_CPT_EDGE(pwm->hwpwm), CPT_EDGE_DISABLED);
348  
349  	if (ret == -ERESTARTSYS)
350  		goto out;
351  
352  	switch (ddata->index) {
353  	case 0:
354  	case 1:
355  		/*
356  		 * Getting here could mean:
357  		 *  - input signal is constant of less than 1 Hz
358  		 *  - there is no input signal at all
359  		 *
360  		 * In such case the frequency is rounded down to 0
361  		 */
362  		result->period = 0;
363  		result->duty_cycle = 0;
364  
365  		break;
366  
367  	case 2:
368  		/* We have everying we need */
369  		high = ddata->snapshot[1] - ddata->snapshot[0];
370  		low = ddata->snapshot[2] - ddata->snapshot[1];
371  
372  		effective_ticks = clk_get_rate(pc->cpt_clk);
373  
374  		result->period = (high + low) * NSEC_PER_SEC;
375  		result->period /= effective_ticks;
376  
377  		result->duty_cycle = high * NSEC_PER_SEC;
378  		result->duty_cycle /= effective_ticks;
379  
380  		break;
381  
382  	default:
383  		dev_err(dev, "internal error\n");
384  		break;
385  	}
386  
387  out:
388  	/* Disable capture */
389  	regmap_field_write(pc->pwm_cpt_en, 0);
390  
391  	mutex_unlock(&ddata->lock);
392  	return ret;
393  }
394  
sti_pwm_apply(struct pwm_chip * chip,struct pwm_device * pwm,const struct pwm_state * state)395  static int sti_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
396  			 const struct pwm_state *state)
397  {
398  	struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
399  	struct sti_pwm_compat_data *cdata = pc->cdata;
400  	struct device *dev = pc->dev;
401  	int err;
402  
403  	if (pwm->hwpwm >= cdata->pwm_num_devs) {
404  		dev_err(dev, "device %u is not valid for pwm mode\n",
405  			pwm->hwpwm);
406  		return -EINVAL;
407  	}
408  
409  	if (state->polarity != PWM_POLARITY_NORMAL)
410  		return -EINVAL;
411  
412  	if (!state->enabled) {
413  		if (pwm->state.enabled)
414  			sti_pwm_disable(chip, pwm);
415  
416  		return 0;
417  	}
418  
419  	err = sti_pwm_config(pwm->chip, pwm, state->duty_cycle, state->period);
420  	if (err)
421  		return err;
422  
423  	if (!pwm->state.enabled)
424  		err = sti_pwm_enable(chip, pwm);
425  
426  	return err;
427  }
428  
429  static const struct pwm_ops sti_pwm_ops = {
430  	.capture = sti_pwm_capture,
431  	.apply = sti_pwm_apply,
432  	.free = sti_pwm_free,
433  	.owner = THIS_MODULE,
434  };
435  
sti_pwm_interrupt(int irq,void * data)436  static irqreturn_t sti_pwm_interrupt(int irq, void *data)
437  {
438  	struct sti_pwm_chip *pc = data;
439  	struct device *dev = pc->dev;
440  	struct sti_cpt_ddata *ddata;
441  	int devicenum;
442  	unsigned int cpt_int_stat;
443  	unsigned int reg;
444  	int ret = IRQ_NONE;
445  
446  	ret = regmap_field_read(pc->pwm_cpt_int_stat, &cpt_int_stat);
447  	if (ret)
448  		return ret;
449  
450  	while (cpt_int_stat) {
451  		devicenum = ffs(cpt_int_stat) - 1;
452  
453  		ddata = &pc->cdata->ddata[devicenum];
454  
455  		/*
456  		 * Capture input:
457  		 *    _______                   _______
458  		 *   |       |                 |       |
459  		 * __|       |_________________|       |________
460  		 *   ^0      ^1                ^2
461  		 *
462  		 * Capture start by the first available rising edge. When a
463  		 * capture event occurs, capture value (CPT_VALx) is stored,
464  		 * index incremented, capture edge changed.
465  		 *
466  		 * After the capture, if the index > 1, we have collected the
467  		 * necessary data so we signal the thread waiting for it and
468  		 * disable the capture by setting capture edge to none
469  		 */
470  
471  		regmap_read(pc->regmap,
472  			    PWM_CPT_VAL(devicenum),
473  			    &ddata->snapshot[ddata->index]);
474  
475  		switch (ddata->index) {
476  		case 0:
477  		case 1:
478  			regmap_read(pc->regmap, PWM_CPT_EDGE(devicenum), &reg);
479  			reg ^= PWM_CPT_EDGE_MASK;
480  			regmap_write(pc->regmap, PWM_CPT_EDGE(devicenum), reg);
481  
482  			ddata->index++;
483  			break;
484  
485  		case 2:
486  			regmap_write(pc->regmap,
487  				     PWM_CPT_EDGE(devicenum),
488  				     CPT_EDGE_DISABLED);
489  			wake_up(&ddata->wait);
490  			break;
491  
492  		default:
493  			dev_err(dev, "Internal error\n");
494  		}
495  
496  		cpt_int_stat &= ~BIT_MASK(devicenum);
497  
498  		ret = IRQ_HANDLED;
499  	}
500  
501  	/* Just ACK everything */
502  	regmap_write(pc->regmap, PWM_INT_ACK, PWM_INT_ACK_MASK);
503  
504  	return ret;
505  }
506  
sti_pwm_probe_dt(struct sti_pwm_chip * pc)507  static int sti_pwm_probe_dt(struct sti_pwm_chip *pc)
508  {
509  	struct device *dev = pc->dev;
510  	const struct reg_field *reg_fields;
511  	struct device_node *np = dev->of_node;
512  	struct sti_pwm_compat_data *cdata = pc->cdata;
513  	u32 num_devs;
514  	int ret;
515  
516  	ret = of_property_read_u32(np, "st,pwm-num-chan", &num_devs);
517  	if (!ret)
518  		cdata->pwm_num_devs = num_devs;
519  
520  	ret = of_property_read_u32(np, "st,capture-num-chan", &num_devs);
521  	if (!ret)
522  		cdata->cpt_num_devs = num_devs;
523  
524  	if (!cdata->pwm_num_devs && !cdata->cpt_num_devs) {
525  		dev_err(dev, "No channels configured\n");
526  		return -EINVAL;
527  	}
528  
529  	reg_fields = cdata->reg_fields;
530  
531  	pc->prescale_low = devm_regmap_field_alloc(dev, pc->regmap,
532  					reg_fields[PWMCLK_PRESCALE_LOW]);
533  	if (IS_ERR(pc->prescale_low))
534  		return PTR_ERR(pc->prescale_low);
535  
536  	pc->prescale_high = devm_regmap_field_alloc(dev, pc->regmap,
537  					reg_fields[PWMCLK_PRESCALE_HIGH]);
538  	if (IS_ERR(pc->prescale_high))
539  		return PTR_ERR(pc->prescale_high);
540  
541  	pc->pwm_out_en = devm_regmap_field_alloc(dev, pc->regmap,
542  						 reg_fields[PWM_OUT_EN]);
543  	if (IS_ERR(pc->pwm_out_en))
544  		return PTR_ERR(pc->pwm_out_en);
545  
546  	pc->pwm_cpt_en = devm_regmap_field_alloc(dev, pc->regmap,
547  						 reg_fields[PWM_CPT_EN]);
548  	if (IS_ERR(pc->pwm_cpt_en))
549  		return PTR_ERR(pc->pwm_cpt_en);
550  
551  	pc->pwm_cpt_int_en = devm_regmap_field_alloc(dev, pc->regmap,
552  						reg_fields[PWM_CPT_INT_EN]);
553  	if (IS_ERR(pc->pwm_cpt_int_en))
554  		return PTR_ERR(pc->pwm_cpt_int_en);
555  
556  	pc->pwm_cpt_int_stat = devm_regmap_field_alloc(dev, pc->regmap,
557  						reg_fields[PWM_CPT_INT_STAT]);
558  	if (PTR_ERR_OR_ZERO(pc->pwm_cpt_int_stat))
559  		return PTR_ERR(pc->pwm_cpt_int_stat);
560  
561  	return 0;
562  }
563  
564  static const struct regmap_config sti_pwm_regmap_config = {
565  	.reg_bits = 32,
566  	.val_bits = 32,
567  	.reg_stride = 4,
568  };
569  
sti_pwm_probe(struct platform_device * pdev)570  static int sti_pwm_probe(struct platform_device *pdev)
571  {
572  	struct device *dev = &pdev->dev;
573  	struct sti_pwm_compat_data *cdata;
574  	struct pwm_chip *chip;
575  	struct sti_pwm_chip *pc;
576  	unsigned int i;
577  	int irq, ret;
578  
579  	pc = devm_kzalloc(dev, sizeof(*pc), GFP_KERNEL);
580  	if (!pc)
581  		return -ENOMEM;
582  	chip = &pc->chip;
583  
584  	cdata = devm_kzalloc(dev, sizeof(*cdata), GFP_KERNEL);
585  	if (!cdata)
586  		return -ENOMEM;
587  
588  	pc->mmio = devm_platform_ioremap_resource(pdev, 0);
589  	if (IS_ERR(pc->mmio))
590  		return PTR_ERR(pc->mmio);
591  
592  	pc->regmap = devm_regmap_init_mmio(dev, pc->mmio,
593  					   &sti_pwm_regmap_config);
594  	if (IS_ERR(pc->regmap))
595  		return PTR_ERR(pc->regmap);
596  
597  	irq = platform_get_irq(pdev, 0);
598  	if (irq < 0)
599  		return irq;
600  
601  	ret = devm_request_irq(&pdev->dev, irq, sti_pwm_interrupt, 0,
602  			       pdev->name, pc);
603  	if (ret < 0) {
604  		dev_err(&pdev->dev, "Failed to request IRQ\n");
605  		return ret;
606  	}
607  
608  	/*
609  	 * Setup PWM data with default values: some values could be replaced
610  	 * with specific ones provided from Device Tree.
611  	 */
612  	cdata->reg_fields = sti_pwm_regfields;
613  	cdata->max_prescale = 0xff;
614  	cdata->max_pwm_cnt = 255;
615  	cdata->pwm_num_devs = 0;
616  	cdata->cpt_num_devs = 0;
617  
618  	pc->cdata = cdata;
619  	pc->dev = dev;
620  	pc->en_count = 0;
621  	mutex_init(&pc->sti_pwm_lock);
622  
623  	ret = sti_pwm_probe_dt(pc);
624  	if (ret)
625  		return ret;
626  
627  	if (cdata->pwm_num_devs) {
628  		pc->pwm_clk = devm_clk_get_prepared(dev, "pwm");
629  		if (IS_ERR(pc->pwm_clk)) {
630  			dev_err(dev, "failed to get PWM clock\n");
631  			return PTR_ERR(pc->pwm_clk);
632  		}
633  	}
634  
635  	if (cdata->cpt_num_devs) {
636  		pc->cpt_clk = devm_clk_get_prepared(dev, "capture");
637  		if (IS_ERR(pc->cpt_clk)) {
638  			dev_err(dev, "failed to get PWM capture clock\n");
639  			return PTR_ERR(pc->cpt_clk);
640  		}
641  
642  		cdata->ddata = devm_kzalloc(dev, cdata->cpt_num_devs * sizeof(*cdata->ddata), GFP_KERNEL);
643  		if (!cdata->ddata)
644  			return -ENOMEM;
645  	}
646  
647  	chip->dev = dev;
648  	chip->ops = &sti_pwm_ops;
649  	chip->npwm = max(cdata->pwm_num_devs, cdata->cpt_num_devs);
650  
651  	for (i = 0; i < cdata->cpt_num_devs; i++) {
652  		struct sti_cpt_ddata *ddata = &cdata->ddata[i];
653  
654  		init_waitqueue_head(&ddata->wait);
655  		mutex_init(&ddata->lock);
656  	}
657  
658  	return devm_pwmchip_add(dev, chip);
659  }
660  
661  static const struct of_device_id sti_pwm_of_match[] = {
662  	{ .compatible = "st,sti-pwm", },
663  	{ /* sentinel */ }
664  };
665  MODULE_DEVICE_TABLE(of, sti_pwm_of_match);
666  
667  static struct platform_driver sti_pwm_driver = {
668  	.driver = {
669  		.name = "sti-pwm",
670  		.of_match_table = sti_pwm_of_match,
671  	},
672  	.probe = sti_pwm_probe,
673  };
674  module_platform_driver(sti_pwm_driver);
675  
676  MODULE_AUTHOR("Ajit Pal Singh <ajitpal.singh@st.com>");
677  MODULE_DESCRIPTION("STMicroelectronics ST PWM driver");
678  MODULE_LICENSE("GPL");
679