xref: /linux/drivers/iio/trigger/stm32-timer-trigger.c (revision 6fdcba32711044c35c0e1b094cbd8f3f0b4472c9)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) STMicroelectronics 2016
4  *
5  * Author: Benjamin Gaignard <benjamin.gaignard@st.com>
6  *
7  */
8 
9 #include <linux/iio/iio.h>
10 #include <linux/iio/sysfs.h>
11 #include <linux/iio/timer/stm32-timer-trigger.h>
12 #include <linux/iio/trigger.h>
13 #include <linux/mfd/stm32-timers.h>
14 #include <linux/module.h>
15 #include <linux/platform_device.h>
16 #include <linux/of_device.h>
17 
18 #define MAX_TRIGGERS 7
19 #define MAX_VALIDS 5
20 
21 /* List the triggers created by each timer */
22 static const void *triggers_table[][MAX_TRIGGERS] = {
23 	{ TIM1_TRGO, TIM1_TRGO2, TIM1_CH1, TIM1_CH2, TIM1_CH3, TIM1_CH4,},
24 	{ TIM2_TRGO, TIM2_CH1, TIM2_CH2, TIM2_CH3, TIM2_CH4,},
25 	{ TIM3_TRGO, TIM3_CH1, TIM3_CH2, TIM3_CH3, TIM3_CH4,},
26 	{ TIM4_TRGO, TIM4_CH1, TIM4_CH2, TIM4_CH3, TIM4_CH4,},
27 	{ TIM5_TRGO, TIM5_CH1, TIM5_CH2, TIM5_CH3, TIM5_CH4,},
28 	{ TIM6_TRGO,},
29 	{ TIM7_TRGO,},
30 	{ TIM8_TRGO, TIM8_TRGO2, TIM8_CH1, TIM8_CH2, TIM8_CH3, TIM8_CH4,},
31 	{ TIM9_TRGO, TIM9_CH1, TIM9_CH2,},
32 	{ TIM10_OC1,},
33 	{ TIM11_OC1,},
34 	{ TIM12_TRGO, TIM12_CH1, TIM12_CH2,},
35 	{ TIM13_OC1,},
36 	{ TIM14_OC1,},
37 	{ TIM15_TRGO,},
38 	{ TIM16_OC1,},
39 	{ TIM17_OC1,},
40 };
41 
42 /* List the triggers accepted by each timer */
43 static const void *valids_table[][MAX_VALIDS] = {
44 	{ TIM5_TRGO, TIM2_TRGO, TIM3_TRGO, TIM4_TRGO,},
45 	{ TIM1_TRGO, TIM8_TRGO, TIM3_TRGO, TIM4_TRGO,},
46 	{ TIM1_TRGO, TIM2_TRGO, TIM5_TRGO, TIM4_TRGO,},
47 	{ TIM1_TRGO, TIM2_TRGO, TIM3_TRGO, TIM8_TRGO,},
48 	{ TIM2_TRGO, TIM3_TRGO, TIM4_TRGO, TIM8_TRGO,},
49 	{ }, /* timer 6 */
50 	{ }, /* timer 7 */
51 	{ TIM1_TRGO, TIM2_TRGO, TIM4_TRGO, TIM5_TRGO,},
52 	{ TIM2_TRGO, TIM3_TRGO, TIM10_OC1, TIM11_OC1,},
53 	{ }, /* timer 10 */
54 	{ }, /* timer 11 */
55 	{ TIM4_TRGO, TIM5_TRGO, TIM13_OC1, TIM14_OC1,},
56 };
57 
58 static const void *stm32h7_valids_table[][MAX_VALIDS] = {
59 	{ TIM15_TRGO, TIM2_TRGO, TIM3_TRGO, TIM4_TRGO,},
60 	{ TIM1_TRGO, TIM8_TRGO, TIM3_TRGO, TIM4_TRGO,},
61 	{ TIM1_TRGO, TIM2_TRGO, TIM15_TRGO, TIM4_TRGO,},
62 	{ TIM1_TRGO, TIM2_TRGO, TIM3_TRGO, TIM8_TRGO,},
63 	{ TIM1_TRGO, TIM8_TRGO, TIM3_TRGO, TIM4_TRGO,},
64 	{ }, /* timer 6 */
65 	{ }, /* timer 7 */
66 	{ TIM1_TRGO, TIM2_TRGO, TIM4_TRGO, TIM5_TRGO,},
67 	{ }, /* timer 9 */
68 	{ }, /* timer 10 */
69 	{ }, /* timer 11 */
70 	{ TIM4_TRGO, TIM5_TRGO, TIM13_OC1, TIM14_OC1,},
71 	{ }, /* timer 13 */
72 	{ }, /* timer 14 */
73 	{ TIM1_TRGO, TIM3_TRGO, TIM16_OC1, TIM17_OC1,},
74 	{ }, /* timer 16 */
75 	{ }, /* timer 17 */
76 };
77 
78 struct stm32_timer_trigger {
79 	struct device *dev;
80 	struct regmap *regmap;
81 	struct clk *clk;
82 	u32 max_arr;
83 	const void *triggers;
84 	const void *valids;
85 	bool has_trgo2;
86 };
87 
88 struct stm32_timer_trigger_cfg {
89 	const void *(*valids_table)[MAX_VALIDS];
90 	const unsigned int num_valids_table;
91 };
92 
93 static bool stm32_timer_is_trgo2_name(const char *name)
94 {
95 	return !!strstr(name, "trgo2");
96 }
97 
98 static bool stm32_timer_is_trgo_name(const char *name)
99 {
100 	return (!!strstr(name, "trgo") && !strstr(name, "trgo2"));
101 }
102 
103 static int stm32_timer_start(struct stm32_timer_trigger *priv,
104 			     struct iio_trigger *trig,
105 			     unsigned int frequency)
106 {
107 	unsigned long long prd, div;
108 	int prescaler = 0;
109 	u32 ccer, cr1;
110 
111 	/* Period and prescaler values depends of clock rate */
112 	div = (unsigned long long)clk_get_rate(priv->clk);
113 
114 	do_div(div, frequency);
115 
116 	prd = div;
117 
118 	/*
119 	 * Increase prescaler value until we get a result that fit
120 	 * with auto reload register maximum value.
121 	 */
122 	while (div > priv->max_arr) {
123 		prescaler++;
124 		div = prd;
125 		do_div(div, (prescaler + 1));
126 	}
127 	prd = div;
128 
129 	if (prescaler > MAX_TIM_PSC) {
130 		dev_err(priv->dev, "prescaler exceeds the maximum value\n");
131 		return -EINVAL;
132 	}
133 
134 	/* Check if nobody else use the timer */
135 	regmap_read(priv->regmap, TIM_CCER, &ccer);
136 	if (ccer & TIM_CCER_CCXE)
137 		return -EBUSY;
138 
139 	regmap_read(priv->regmap, TIM_CR1, &cr1);
140 	if (!(cr1 & TIM_CR1_CEN))
141 		clk_enable(priv->clk);
142 
143 	regmap_write(priv->regmap, TIM_PSC, prescaler);
144 	regmap_write(priv->regmap, TIM_ARR, prd - 1);
145 	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, TIM_CR1_ARPE);
146 
147 	/* Force master mode to update mode */
148 	if (stm32_timer_is_trgo2_name(trig->name))
149 		regmap_update_bits(priv->regmap, TIM_CR2, TIM_CR2_MMS2,
150 				   0x2 << TIM_CR2_MMS2_SHIFT);
151 	else
152 		regmap_update_bits(priv->regmap, TIM_CR2, TIM_CR2_MMS,
153 				   0x2 << TIM_CR2_MMS_SHIFT);
154 
155 	/* Make sure that registers are updated */
156 	regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
157 
158 	/* Enable controller */
159 	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, TIM_CR1_CEN);
160 
161 	return 0;
162 }
163 
164 static void stm32_timer_stop(struct stm32_timer_trigger *priv)
165 {
166 	u32 ccer, cr1;
167 
168 	regmap_read(priv->regmap, TIM_CCER, &ccer);
169 	if (ccer & TIM_CCER_CCXE)
170 		return;
171 
172 	regmap_read(priv->regmap, TIM_CR1, &cr1);
173 	if (cr1 & TIM_CR1_CEN)
174 		clk_disable(priv->clk);
175 
176 	/* Stop timer */
177 	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, 0);
178 	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
179 	regmap_write(priv->regmap, TIM_PSC, 0);
180 	regmap_write(priv->regmap, TIM_ARR, 0);
181 
182 	/* Make sure that registers are updated */
183 	regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
184 }
185 
186 static ssize_t stm32_tt_store_frequency(struct device *dev,
187 					struct device_attribute *attr,
188 					const char *buf, size_t len)
189 {
190 	struct iio_trigger *trig = to_iio_trigger(dev);
191 	struct stm32_timer_trigger *priv = iio_trigger_get_drvdata(trig);
192 	unsigned int freq;
193 	int ret;
194 
195 	ret = kstrtouint(buf, 10, &freq);
196 	if (ret)
197 		return ret;
198 
199 	if (freq == 0) {
200 		stm32_timer_stop(priv);
201 	} else {
202 		ret = stm32_timer_start(priv, trig, freq);
203 		if (ret)
204 			return ret;
205 	}
206 
207 	return len;
208 }
209 
210 static ssize_t stm32_tt_read_frequency(struct device *dev,
211 				       struct device_attribute *attr, char *buf)
212 {
213 	struct iio_trigger *trig = to_iio_trigger(dev);
214 	struct stm32_timer_trigger *priv = iio_trigger_get_drvdata(trig);
215 	u32 psc, arr, cr1;
216 	unsigned long long freq = 0;
217 
218 	regmap_read(priv->regmap, TIM_CR1, &cr1);
219 	regmap_read(priv->regmap, TIM_PSC, &psc);
220 	regmap_read(priv->regmap, TIM_ARR, &arr);
221 
222 	if (cr1 & TIM_CR1_CEN) {
223 		freq = (unsigned long long)clk_get_rate(priv->clk);
224 		do_div(freq, psc + 1);
225 		do_div(freq, arr + 1);
226 	}
227 
228 	return sprintf(buf, "%d\n", (unsigned int)freq);
229 }
230 
231 static IIO_DEV_ATTR_SAMP_FREQ(0660,
232 			      stm32_tt_read_frequency,
233 			      stm32_tt_store_frequency);
234 
235 #define MASTER_MODE_MAX		7
236 #define MASTER_MODE2_MAX	15
237 
238 static char *master_mode_table[] = {
239 	"reset",
240 	"enable",
241 	"update",
242 	"compare_pulse",
243 	"OC1REF",
244 	"OC2REF",
245 	"OC3REF",
246 	"OC4REF",
247 	/* Master mode selection 2 only */
248 	"OC5REF",
249 	"OC6REF",
250 	"compare_pulse_OC4REF",
251 	"compare_pulse_OC6REF",
252 	"compare_pulse_OC4REF_r_or_OC6REF_r",
253 	"compare_pulse_OC4REF_r_or_OC6REF_f",
254 	"compare_pulse_OC5REF_r_or_OC6REF_r",
255 	"compare_pulse_OC5REF_r_or_OC6REF_f",
256 };
257 
258 static ssize_t stm32_tt_show_master_mode(struct device *dev,
259 					 struct device_attribute *attr,
260 					 char *buf)
261 {
262 	struct stm32_timer_trigger *priv = dev_get_drvdata(dev);
263 	struct iio_trigger *trig = to_iio_trigger(dev);
264 	u32 cr2;
265 
266 	regmap_read(priv->regmap, TIM_CR2, &cr2);
267 
268 	if (stm32_timer_is_trgo2_name(trig->name))
269 		cr2 = (cr2 & TIM_CR2_MMS2) >> TIM_CR2_MMS2_SHIFT;
270 	else
271 		cr2 = (cr2 & TIM_CR2_MMS) >> TIM_CR2_MMS_SHIFT;
272 
273 	return snprintf(buf, PAGE_SIZE, "%s\n", master_mode_table[cr2]);
274 }
275 
276 static ssize_t stm32_tt_store_master_mode(struct device *dev,
277 					  struct device_attribute *attr,
278 					  const char *buf, size_t len)
279 {
280 	struct stm32_timer_trigger *priv = dev_get_drvdata(dev);
281 	struct iio_trigger *trig = to_iio_trigger(dev);
282 	u32 mask, shift, master_mode_max;
283 	int i;
284 
285 	if (stm32_timer_is_trgo2_name(trig->name)) {
286 		mask = TIM_CR2_MMS2;
287 		shift = TIM_CR2_MMS2_SHIFT;
288 		master_mode_max = MASTER_MODE2_MAX;
289 	} else {
290 		mask = TIM_CR2_MMS;
291 		shift = TIM_CR2_MMS_SHIFT;
292 		master_mode_max = MASTER_MODE_MAX;
293 	}
294 
295 	for (i = 0; i <= master_mode_max; i++) {
296 		if (!strncmp(master_mode_table[i], buf,
297 			     strlen(master_mode_table[i]))) {
298 			regmap_update_bits(priv->regmap, TIM_CR2, mask,
299 					   i << shift);
300 			/* Make sure that registers are updated */
301 			regmap_update_bits(priv->regmap, TIM_EGR,
302 					   TIM_EGR_UG, TIM_EGR_UG);
303 			return len;
304 		}
305 	}
306 
307 	return -EINVAL;
308 }
309 
310 static ssize_t stm32_tt_show_master_mode_avail(struct device *dev,
311 					       struct device_attribute *attr,
312 					       char *buf)
313 {
314 	struct iio_trigger *trig = to_iio_trigger(dev);
315 	unsigned int i, master_mode_max;
316 	size_t len = 0;
317 
318 	if (stm32_timer_is_trgo2_name(trig->name))
319 		master_mode_max = MASTER_MODE2_MAX;
320 	else
321 		master_mode_max = MASTER_MODE_MAX;
322 
323 	for (i = 0; i <= master_mode_max; i++)
324 		len += scnprintf(buf + len, PAGE_SIZE - len,
325 			"%s ", master_mode_table[i]);
326 
327 	/* replace trailing space by newline */
328 	buf[len - 1] = '\n';
329 
330 	return len;
331 }
332 
333 static IIO_DEVICE_ATTR(master_mode_available, 0444,
334 		       stm32_tt_show_master_mode_avail, NULL, 0);
335 
336 static IIO_DEVICE_ATTR(master_mode, 0660,
337 		       stm32_tt_show_master_mode,
338 		       stm32_tt_store_master_mode,
339 		       0);
340 
341 static struct attribute *stm32_trigger_attrs[] = {
342 	&iio_dev_attr_sampling_frequency.dev_attr.attr,
343 	&iio_dev_attr_master_mode.dev_attr.attr,
344 	&iio_dev_attr_master_mode_available.dev_attr.attr,
345 	NULL,
346 };
347 
348 static const struct attribute_group stm32_trigger_attr_group = {
349 	.attrs = stm32_trigger_attrs,
350 };
351 
352 static const struct attribute_group *stm32_trigger_attr_groups[] = {
353 	&stm32_trigger_attr_group,
354 	NULL,
355 };
356 
357 static const struct iio_trigger_ops timer_trigger_ops = {
358 };
359 
360 static int stm32_setup_iio_triggers(struct stm32_timer_trigger *priv)
361 {
362 	int ret;
363 	const char * const *cur = priv->triggers;
364 
365 	while (cur && *cur) {
366 		struct iio_trigger *trig;
367 		bool cur_is_trgo = stm32_timer_is_trgo_name(*cur);
368 		bool cur_is_trgo2 = stm32_timer_is_trgo2_name(*cur);
369 
370 		if (cur_is_trgo2 && !priv->has_trgo2) {
371 			cur++;
372 			continue;
373 		}
374 
375 		trig = devm_iio_trigger_alloc(priv->dev, "%s", *cur);
376 		if  (!trig)
377 			return -ENOMEM;
378 
379 		trig->dev.parent = priv->dev->parent;
380 		trig->ops = &timer_trigger_ops;
381 
382 		/*
383 		 * sampling frequency and master mode attributes
384 		 * should only be available on trgo/trgo2 triggers
385 		 */
386 		if (cur_is_trgo || cur_is_trgo2)
387 			trig->dev.groups = stm32_trigger_attr_groups;
388 
389 		iio_trigger_set_drvdata(trig, priv);
390 
391 		ret = devm_iio_trigger_register(priv->dev, trig);
392 		if (ret)
393 			return ret;
394 		cur++;
395 	}
396 
397 	return 0;
398 }
399 
400 static int stm32_counter_read_raw(struct iio_dev *indio_dev,
401 				  struct iio_chan_spec const *chan,
402 				  int *val, int *val2, long mask)
403 {
404 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
405 	u32 dat;
406 
407 	switch (mask) {
408 	case IIO_CHAN_INFO_RAW:
409 		regmap_read(priv->regmap, TIM_CNT, &dat);
410 		*val = dat;
411 		return IIO_VAL_INT;
412 
413 	case IIO_CHAN_INFO_ENABLE:
414 		regmap_read(priv->regmap, TIM_CR1, &dat);
415 		*val = (dat & TIM_CR1_CEN) ? 1 : 0;
416 		return IIO_VAL_INT;
417 
418 	case IIO_CHAN_INFO_SCALE:
419 		regmap_read(priv->regmap, TIM_SMCR, &dat);
420 		dat &= TIM_SMCR_SMS;
421 
422 		*val = 1;
423 		*val2 = 0;
424 
425 		/* in quadrature case scale = 0.25 */
426 		if (dat == 3)
427 			*val2 = 2;
428 
429 		return IIO_VAL_FRACTIONAL_LOG2;
430 	}
431 
432 	return -EINVAL;
433 }
434 
435 static int stm32_counter_write_raw(struct iio_dev *indio_dev,
436 				   struct iio_chan_spec const *chan,
437 				   int val, int val2, long mask)
438 {
439 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
440 	u32 dat;
441 
442 	switch (mask) {
443 	case IIO_CHAN_INFO_RAW:
444 		return regmap_write(priv->regmap, TIM_CNT, val);
445 
446 	case IIO_CHAN_INFO_SCALE:
447 		/* fixed scale */
448 		return -EINVAL;
449 
450 	case IIO_CHAN_INFO_ENABLE:
451 		if (val) {
452 			regmap_read(priv->regmap, TIM_CR1, &dat);
453 			if (!(dat & TIM_CR1_CEN))
454 				clk_enable(priv->clk);
455 			regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN,
456 					   TIM_CR1_CEN);
457 		} else {
458 			regmap_read(priv->regmap, TIM_CR1, &dat);
459 			regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN,
460 					   0);
461 			if (dat & TIM_CR1_CEN)
462 				clk_disable(priv->clk);
463 		}
464 		return 0;
465 	}
466 
467 	return -EINVAL;
468 }
469 
470 static int stm32_counter_validate_trigger(struct iio_dev *indio_dev,
471 					  struct iio_trigger *trig)
472 {
473 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
474 	const char * const *cur = priv->valids;
475 	unsigned int i = 0;
476 
477 	if (!is_stm32_timer_trigger(trig))
478 		return -EINVAL;
479 
480 	while (cur && *cur) {
481 		if (!strncmp(trig->name, *cur, strlen(trig->name))) {
482 			regmap_update_bits(priv->regmap,
483 					   TIM_SMCR, TIM_SMCR_TS,
484 					   i << TIM_SMCR_TS_SHIFT);
485 			return 0;
486 		}
487 		cur++;
488 		i++;
489 	}
490 
491 	return -EINVAL;
492 }
493 
494 static const struct iio_info stm32_trigger_info = {
495 	.validate_trigger = stm32_counter_validate_trigger,
496 	.read_raw = stm32_counter_read_raw,
497 	.write_raw = stm32_counter_write_raw
498 };
499 
500 static const char *const stm32_trigger_modes[] = {
501 	"trigger",
502 };
503 
504 static int stm32_set_trigger_mode(struct iio_dev *indio_dev,
505 				  const struct iio_chan_spec *chan,
506 				  unsigned int mode)
507 {
508 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
509 
510 	regmap_update_bits(priv->regmap, TIM_SMCR, TIM_SMCR_SMS, TIM_SMCR_SMS);
511 
512 	return 0;
513 }
514 
515 static int stm32_get_trigger_mode(struct iio_dev *indio_dev,
516 				  const struct iio_chan_spec *chan)
517 {
518 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
519 	u32 smcr;
520 
521 	regmap_read(priv->regmap, TIM_SMCR, &smcr);
522 
523 	return (smcr & TIM_SMCR_SMS) == TIM_SMCR_SMS ? 0 : -EINVAL;
524 }
525 
526 static const struct iio_enum stm32_trigger_mode_enum = {
527 	.items = stm32_trigger_modes,
528 	.num_items = ARRAY_SIZE(stm32_trigger_modes),
529 	.set = stm32_set_trigger_mode,
530 	.get = stm32_get_trigger_mode
531 };
532 
533 static const char *const stm32_enable_modes[] = {
534 	"always",
535 	"gated",
536 	"triggered",
537 };
538 
539 static int stm32_enable_mode2sms(int mode)
540 {
541 	switch (mode) {
542 	case 0:
543 		return 0;
544 	case 1:
545 		return 5;
546 	case 2:
547 		return 6;
548 	}
549 
550 	return -EINVAL;
551 }
552 
553 static int stm32_set_enable_mode(struct iio_dev *indio_dev,
554 				 const struct iio_chan_spec *chan,
555 				 unsigned int mode)
556 {
557 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
558 	int sms = stm32_enable_mode2sms(mode);
559 	u32 val;
560 
561 	if (sms < 0)
562 		return sms;
563 	/*
564 	 * Triggered mode sets CEN bit automatically by hardware. So, first
565 	 * enable counter clock, so it can use it. Keeps it in sync with CEN.
566 	 */
567 	if (sms == 6) {
568 		regmap_read(priv->regmap, TIM_CR1, &val);
569 		if (!(val & TIM_CR1_CEN))
570 			clk_enable(priv->clk);
571 	}
572 
573 	regmap_update_bits(priv->regmap, TIM_SMCR, TIM_SMCR_SMS, sms);
574 
575 	return 0;
576 }
577 
578 static int stm32_sms2enable_mode(int mode)
579 {
580 	switch (mode) {
581 	case 0:
582 		return 0;
583 	case 5:
584 		return 1;
585 	case 6:
586 		return 2;
587 	}
588 
589 	return -EINVAL;
590 }
591 
592 static int stm32_get_enable_mode(struct iio_dev *indio_dev,
593 				 const struct iio_chan_spec *chan)
594 {
595 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
596 	u32 smcr;
597 
598 	regmap_read(priv->regmap, TIM_SMCR, &smcr);
599 	smcr &= TIM_SMCR_SMS;
600 
601 	return stm32_sms2enable_mode(smcr);
602 }
603 
604 static const struct iio_enum stm32_enable_mode_enum = {
605 	.items = stm32_enable_modes,
606 	.num_items = ARRAY_SIZE(stm32_enable_modes),
607 	.set = stm32_set_enable_mode,
608 	.get = stm32_get_enable_mode
609 };
610 
611 static ssize_t stm32_count_get_preset(struct iio_dev *indio_dev,
612 				      uintptr_t private,
613 				      const struct iio_chan_spec *chan,
614 				      char *buf)
615 {
616 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
617 	u32 arr;
618 
619 	regmap_read(priv->regmap, TIM_ARR, &arr);
620 
621 	return snprintf(buf, PAGE_SIZE, "%u\n", arr);
622 }
623 
624 static ssize_t stm32_count_set_preset(struct iio_dev *indio_dev,
625 				      uintptr_t private,
626 				      const struct iio_chan_spec *chan,
627 				      const char *buf, size_t len)
628 {
629 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
630 	unsigned int preset;
631 	int ret;
632 
633 	ret = kstrtouint(buf, 0, &preset);
634 	if (ret)
635 		return ret;
636 
637 	/* TIMx_ARR register shouldn't be buffered (ARPE=0) */
638 	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, 0);
639 	regmap_write(priv->regmap, TIM_ARR, preset);
640 
641 	return len;
642 }
643 
644 static const struct iio_chan_spec_ext_info stm32_trigger_count_info[] = {
645 	{
646 		.name = "preset",
647 		.shared = IIO_SEPARATE,
648 		.read = stm32_count_get_preset,
649 		.write = stm32_count_set_preset
650 	},
651 	IIO_ENUM("enable_mode", IIO_SEPARATE, &stm32_enable_mode_enum),
652 	IIO_ENUM_AVAILABLE("enable_mode", &stm32_enable_mode_enum),
653 	IIO_ENUM("trigger_mode", IIO_SEPARATE, &stm32_trigger_mode_enum),
654 	IIO_ENUM_AVAILABLE("trigger_mode", &stm32_trigger_mode_enum),
655 	{}
656 };
657 
658 static const struct iio_chan_spec stm32_trigger_channel = {
659 	.type = IIO_COUNT,
660 	.channel = 0,
661 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
662 			      BIT(IIO_CHAN_INFO_ENABLE) |
663 			      BIT(IIO_CHAN_INFO_SCALE),
664 	.ext_info = stm32_trigger_count_info,
665 	.indexed = 1
666 };
667 
668 static struct stm32_timer_trigger *stm32_setup_counter_device(struct device *dev)
669 {
670 	struct iio_dev *indio_dev;
671 	int ret;
672 
673 	indio_dev = devm_iio_device_alloc(dev,
674 					  sizeof(struct stm32_timer_trigger));
675 	if (!indio_dev)
676 		return NULL;
677 
678 	indio_dev->name = dev_name(dev);
679 	indio_dev->dev.parent = dev;
680 	indio_dev->info = &stm32_trigger_info;
681 	indio_dev->modes = INDIO_HARDWARE_TRIGGERED;
682 	indio_dev->num_channels = 1;
683 	indio_dev->channels = &stm32_trigger_channel;
684 	indio_dev->dev.of_node = dev->of_node;
685 
686 	ret = devm_iio_device_register(dev, indio_dev);
687 	if (ret)
688 		return NULL;
689 
690 	return iio_priv(indio_dev);
691 }
692 
693 /**
694  * is_stm32_timer_trigger
695  * @trig: trigger to be checked
696  *
697  * return true if the trigger is a valid stm32 iio timer trigger
698  * either return false
699  */
700 bool is_stm32_timer_trigger(struct iio_trigger *trig)
701 {
702 	return (trig->ops == &timer_trigger_ops);
703 }
704 EXPORT_SYMBOL(is_stm32_timer_trigger);
705 
706 static void stm32_timer_detect_trgo2(struct stm32_timer_trigger *priv)
707 {
708 	u32 val;
709 
710 	/*
711 	 * Master mode selection 2 bits can only be written and read back when
712 	 * timer supports it.
713 	 */
714 	regmap_update_bits(priv->regmap, TIM_CR2, TIM_CR2_MMS2, TIM_CR2_MMS2);
715 	regmap_read(priv->regmap, TIM_CR2, &val);
716 	regmap_update_bits(priv->regmap, TIM_CR2, TIM_CR2_MMS2, 0);
717 	priv->has_trgo2 = !!val;
718 }
719 
720 static int stm32_timer_trigger_probe(struct platform_device *pdev)
721 {
722 	struct device *dev = &pdev->dev;
723 	struct stm32_timer_trigger *priv;
724 	struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent);
725 	const struct stm32_timer_trigger_cfg *cfg;
726 	unsigned int index;
727 	int ret;
728 
729 	if (of_property_read_u32(dev->of_node, "reg", &index))
730 		return -EINVAL;
731 
732 	cfg = (const struct stm32_timer_trigger_cfg *)
733 		of_match_device(dev->driver->of_match_table, dev)->data;
734 
735 	if (index >= ARRAY_SIZE(triggers_table) ||
736 	    index >= cfg->num_valids_table)
737 		return -EINVAL;
738 
739 	/* Create an IIO device only if we have triggers to be validated */
740 	if (*cfg->valids_table[index])
741 		priv = stm32_setup_counter_device(dev);
742 	else
743 		priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
744 
745 	if (!priv)
746 		return -ENOMEM;
747 
748 	priv->dev = dev;
749 	priv->regmap = ddata->regmap;
750 	priv->clk = ddata->clk;
751 	priv->max_arr = ddata->max_arr;
752 	priv->triggers = triggers_table[index];
753 	priv->valids = cfg->valids_table[index];
754 	stm32_timer_detect_trgo2(priv);
755 
756 	ret = stm32_setup_iio_triggers(priv);
757 	if (ret)
758 		return ret;
759 
760 	platform_set_drvdata(pdev, priv);
761 
762 	return 0;
763 }
764 
765 static const struct stm32_timer_trigger_cfg stm32_timer_trg_cfg = {
766 	.valids_table = valids_table,
767 	.num_valids_table = ARRAY_SIZE(valids_table),
768 };
769 
770 static const struct stm32_timer_trigger_cfg stm32h7_timer_trg_cfg = {
771 	.valids_table = stm32h7_valids_table,
772 	.num_valids_table = ARRAY_SIZE(stm32h7_valids_table),
773 };
774 
775 static const struct of_device_id stm32_trig_of_match[] = {
776 	{
777 		.compatible = "st,stm32-timer-trigger",
778 		.data = (void *)&stm32_timer_trg_cfg,
779 	}, {
780 		.compatible = "st,stm32h7-timer-trigger",
781 		.data = (void *)&stm32h7_timer_trg_cfg,
782 	},
783 	{ /* end node */ },
784 };
785 MODULE_DEVICE_TABLE(of, stm32_trig_of_match);
786 
787 static struct platform_driver stm32_timer_trigger_driver = {
788 	.probe = stm32_timer_trigger_probe,
789 	.driver = {
790 		.name = "stm32-timer-trigger",
791 		.of_match_table = stm32_trig_of_match,
792 	},
793 };
794 module_platform_driver(stm32_timer_trigger_driver);
795 
796 MODULE_ALIAS("platform: stm32-timer-trigger");
797 MODULE_DESCRIPTION("STMicroelectronics STM32 Timer Trigger driver");
798 MODULE_LICENSE("GPL v2");
799