xref: /linux/drivers/iio/trigger/stm32-timer-trigger.c (revision e2fb65594cae9a016fab4639a5d22a914f1e16c8)
1 /*
2  * Copyright (C) STMicroelectronics 2016
3  *
4  * Author: Benjamin Gaignard <benjamin.gaignard@st.com>
5  *
6  * License terms:  GNU General Public License (GPL), version 2
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_CEN, 0);
178 	regmap_write(priv->regmap, TIM_PSC, 0);
179 	regmap_write(priv->regmap, TIM_ARR, 0);
180 
181 	/* Make sure that registers are updated */
182 	regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
183 }
184 
185 static ssize_t stm32_tt_store_frequency(struct device *dev,
186 					struct device_attribute *attr,
187 					const char *buf, size_t len)
188 {
189 	struct iio_trigger *trig = to_iio_trigger(dev);
190 	struct stm32_timer_trigger *priv = iio_trigger_get_drvdata(trig);
191 	unsigned int freq;
192 	int ret;
193 
194 	ret = kstrtouint(buf, 10, &freq);
195 	if (ret)
196 		return ret;
197 
198 	if (freq == 0) {
199 		stm32_timer_stop(priv);
200 	} else {
201 		ret = stm32_timer_start(priv, trig, freq);
202 		if (ret)
203 			return ret;
204 	}
205 
206 	return len;
207 }
208 
209 static ssize_t stm32_tt_read_frequency(struct device *dev,
210 				       struct device_attribute *attr, char *buf)
211 {
212 	struct iio_trigger *trig = to_iio_trigger(dev);
213 	struct stm32_timer_trigger *priv = iio_trigger_get_drvdata(trig);
214 	u32 psc, arr, cr1;
215 	unsigned long long freq = 0;
216 
217 	regmap_read(priv->regmap, TIM_CR1, &cr1);
218 	regmap_read(priv->regmap, TIM_PSC, &psc);
219 	regmap_read(priv->regmap, TIM_ARR, &arr);
220 
221 	if (cr1 & TIM_CR1_CEN) {
222 		freq = (unsigned long long)clk_get_rate(priv->clk);
223 		do_div(freq, psc + 1);
224 		do_div(freq, arr + 1);
225 	}
226 
227 	return sprintf(buf, "%d\n", (unsigned int)freq);
228 }
229 
230 static IIO_DEV_ATTR_SAMP_FREQ(0660,
231 			      stm32_tt_read_frequency,
232 			      stm32_tt_store_frequency);
233 
234 #define MASTER_MODE_MAX		7
235 #define MASTER_MODE2_MAX	15
236 
237 static char *master_mode_table[] = {
238 	"reset",
239 	"enable",
240 	"update",
241 	"compare_pulse",
242 	"OC1REF",
243 	"OC2REF",
244 	"OC3REF",
245 	"OC4REF",
246 	/* Master mode selection 2 only */
247 	"OC5REF",
248 	"OC6REF",
249 	"compare_pulse_OC4REF",
250 	"compare_pulse_OC6REF",
251 	"compare_pulse_OC4REF_r_or_OC6REF_r",
252 	"compare_pulse_OC4REF_r_or_OC6REF_f",
253 	"compare_pulse_OC5REF_r_or_OC6REF_r",
254 	"compare_pulse_OC5REF_r_or_OC6REF_f",
255 };
256 
257 static ssize_t stm32_tt_show_master_mode(struct device *dev,
258 					 struct device_attribute *attr,
259 					 char *buf)
260 {
261 	struct stm32_timer_trigger *priv = dev_get_drvdata(dev);
262 	struct iio_trigger *trig = to_iio_trigger(dev);
263 	u32 cr2;
264 
265 	regmap_read(priv->regmap, TIM_CR2, &cr2);
266 
267 	if (stm32_timer_is_trgo2_name(trig->name))
268 		cr2 = (cr2 & TIM_CR2_MMS2) >> TIM_CR2_MMS2_SHIFT;
269 	else
270 		cr2 = (cr2 & TIM_CR2_MMS) >> TIM_CR2_MMS_SHIFT;
271 
272 	return snprintf(buf, PAGE_SIZE, "%s\n", master_mode_table[cr2]);
273 }
274 
275 static ssize_t stm32_tt_store_master_mode(struct device *dev,
276 					  struct device_attribute *attr,
277 					  const char *buf, size_t len)
278 {
279 	struct stm32_timer_trigger *priv = dev_get_drvdata(dev);
280 	struct iio_trigger *trig = to_iio_trigger(dev);
281 	u32 mask, shift, master_mode_max;
282 	int i;
283 
284 	if (stm32_timer_is_trgo2_name(trig->name)) {
285 		mask = TIM_CR2_MMS2;
286 		shift = TIM_CR2_MMS2_SHIFT;
287 		master_mode_max = MASTER_MODE2_MAX;
288 	} else {
289 		mask = TIM_CR2_MMS;
290 		shift = TIM_CR2_MMS_SHIFT;
291 		master_mode_max = MASTER_MODE_MAX;
292 	}
293 
294 	for (i = 0; i <= master_mode_max; i++) {
295 		if (!strncmp(master_mode_table[i], buf,
296 			     strlen(master_mode_table[i]))) {
297 			regmap_update_bits(priv->regmap, TIM_CR2, mask,
298 					   i << shift);
299 			/* Make sure that registers are updated */
300 			regmap_update_bits(priv->regmap, TIM_EGR,
301 					   TIM_EGR_UG, TIM_EGR_UG);
302 			return len;
303 		}
304 	}
305 
306 	return -EINVAL;
307 }
308 
309 static ssize_t stm32_tt_show_master_mode_avail(struct device *dev,
310 					       struct device_attribute *attr,
311 					       char *buf)
312 {
313 	struct iio_trigger *trig = to_iio_trigger(dev);
314 	unsigned int i, master_mode_max;
315 	size_t len = 0;
316 
317 	if (stm32_timer_is_trgo2_name(trig->name))
318 		master_mode_max = MASTER_MODE2_MAX;
319 	else
320 		master_mode_max = MASTER_MODE_MAX;
321 
322 	for (i = 0; i <= master_mode_max; i++)
323 		len += scnprintf(buf + len, PAGE_SIZE - len,
324 			"%s ", master_mode_table[i]);
325 
326 	/* replace trailing space by newline */
327 	buf[len - 1] = '\n';
328 
329 	return len;
330 }
331 
332 static IIO_DEVICE_ATTR(master_mode_available, 0444,
333 		       stm32_tt_show_master_mode_avail, NULL, 0);
334 
335 static IIO_DEVICE_ATTR(master_mode, 0660,
336 		       stm32_tt_show_master_mode,
337 		       stm32_tt_store_master_mode,
338 		       0);
339 
340 static struct attribute *stm32_trigger_attrs[] = {
341 	&iio_dev_attr_sampling_frequency.dev_attr.attr,
342 	&iio_dev_attr_master_mode.dev_attr.attr,
343 	&iio_dev_attr_master_mode_available.dev_attr.attr,
344 	NULL,
345 };
346 
347 static const struct attribute_group stm32_trigger_attr_group = {
348 	.attrs = stm32_trigger_attrs,
349 };
350 
351 static const struct attribute_group *stm32_trigger_attr_groups[] = {
352 	&stm32_trigger_attr_group,
353 	NULL,
354 };
355 
356 static const struct iio_trigger_ops timer_trigger_ops = {
357 	.owner = THIS_MODULE,
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 	.driver_module = THIS_MODULE,
496 	.validate_trigger = stm32_counter_validate_trigger,
497 	.read_raw = stm32_counter_read_raw,
498 	.write_raw = stm32_counter_write_raw
499 };
500 
501 static const char *const stm32_trigger_modes[] = {
502 	"trigger",
503 };
504 
505 static int stm32_set_trigger_mode(struct iio_dev *indio_dev,
506 				  const struct iio_chan_spec *chan,
507 				  unsigned int mode)
508 {
509 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
510 
511 	regmap_update_bits(priv->regmap, TIM_SMCR, TIM_SMCR_SMS, TIM_SMCR_SMS);
512 
513 	return 0;
514 }
515 
516 static int stm32_get_trigger_mode(struct iio_dev *indio_dev,
517 				  const struct iio_chan_spec *chan)
518 {
519 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
520 	u32 smcr;
521 
522 	regmap_read(priv->regmap, TIM_SMCR, &smcr);
523 
524 	return (smcr & TIM_SMCR_SMS) == TIM_SMCR_SMS ? 0 : -EINVAL;
525 }
526 
527 static const struct iio_enum stm32_trigger_mode_enum = {
528 	.items = stm32_trigger_modes,
529 	.num_items = ARRAY_SIZE(stm32_trigger_modes),
530 	.set = stm32_set_trigger_mode,
531 	.get = stm32_get_trigger_mode
532 };
533 
534 static const char *const stm32_enable_modes[] = {
535 	"always",
536 	"gated",
537 	"triggered",
538 };
539 
540 static int stm32_enable_mode2sms(int mode)
541 {
542 	switch (mode) {
543 	case 0:
544 		return 0;
545 	case 1:
546 		return 5;
547 	case 2:
548 		return 6;
549 	}
550 
551 	return -EINVAL;
552 }
553 
554 static int stm32_set_enable_mode(struct iio_dev *indio_dev,
555 				 const struct iio_chan_spec *chan,
556 				 unsigned int mode)
557 {
558 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
559 	int sms = stm32_enable_mode2sms(mode);
560 	u32 val;
561 
562 	if (sms < 0)
563 		return sms;
564 	/*
565 	 * Triggered mode sets CEN bit automatically by hardware. So, first
566 	 * enable counter clock, so it can use it. Keeps it in sync with CEN.
567 	 */
568 	if (sms == 6) {
569 		regmap_read(priv->regmap, TIM_CR1, &val);
570 		if (!(val & TIM_CR1_CEN))
571 			clk_enable(priv->clk);
572 	}
573 
574 	regmap_update_bits(priv->regmap, TIM_SMCR, TIM_SMCR_SMS, sms);
575 
576 	return 0;
577 }
578 
579 static int stm32_sms2enable_mode(int mode)
580 {
581 	switch (mode) {
582 	case 0:
583 		return 0;
584 	case 5:
585 		return 1;
586 	case 6:
587 		return 2;
588 	}
589 
590 	return -EINVAL;
591 }
592 
593 static int stm32_get_enable_mode(struct iio_dev *indio_dev,
594 				 const struct iio_chan_spec *chan)
595 {
596 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
597 	u32 smcr;
598 
599 	regmap_read(priv->regmap, TIM_SMCR, &smcr);
600 	smcr &= TIM_SMCR_SMS;
601 
602 	return stm32_sms2enable_mode(smcr);
603 }
604 
605 static const struct iio_enum stm32_enable_mode_enum = {
606 	.items = stm32_enable_modes,
607 	.num_items = ARRAY_SIZE(stm32_enable_modes),
608 	.set = stm32_set_enable_mode,
609 	.get = stm32_get_enable_mode
610 };
611 
612 static const char *const stm32_quadrature_modes[] = {
613 	"channel_A",
614 	"channel_B",
615 	"quadrature",
616 };
617 
618 static int stm32_set_quadrature_mode(struct iio_dev *indio_dev,
619 				     const struct iio_chan_spec *chan,
620 				     unsigned int mode)
621 {
622 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
623 
624 	regmap_update_bits(priv->regmap, TIM_SMCR, TIM_SMCR_SMS, mode + 1);
625 
626 	return 0;
627 }
628 
629 static int stm32_get_quadrature_mode(struct iio_dev *indio_dev,
630 				     const struct iio_chan_spec *chan)
631 {
632 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
633 	u32 smcr;
634 	int mode;
635 
636 	regmap_read(priv->regmap, TIM_SMCR, &smcr);
637 	mode = (smcr & TIM_SMCR_SMS) - 1;
638 	if ((mode < 0) || (mode > ARRAY_SIZE(stm32_quadrature_modes)))
639 		return -EINVAL;
640 
641 	return mode;
642 }
643 
644 static const struct iio_enum stm32_quadrature_mode_enum = {
645 	.items = stm32_quadrature_modes,
646 	.num_items = ARRAY_SIZE(stm32_quadrature_modes),
647 	.set = stm32_set_quadrature_mode,
648 	.get = stm32_get_quadrature_mode
649 };
650 
651 static const char *const stm32_count_direction_states[] = {
652 	"up",
653 	"down"
654 };
655 
656 static int stm32_set_count_direction(struct iio_dev *indio_dev,
657 				     const struct iio_chan_spec *chan,
658 				     unsigned int dir)
659 {
660 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
661 	u32 val;
662 	int mode;
663 
664 	/* In encoder mode, direction is RO (given by TI1/TI2 signals) */
665 	regmap_read(priv->regmap, TIM_SMCR, &val);
666 	mode = (val & TIM_SMCR_SMS) - 1;
667 	if ((mode >= 0) || (mode < ARRAY_SIZE(stm32_quadrature_modes)))
668 		return -EBUSY;
669 
670 	return regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_DIR,
671 				  dir ? TIM_CR1_DIR : 0);
672 }
673 
674 static int stm32_get_count_direction(struct iio_dev *indio_dev,
675 				     const struct iio_chan_spec *chan)
676 {
677 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
678 	u32 cr1;
679 
680 	regmap_read(priv->regmap, TIM_CR1, &cr1);
681 
682 	return ((cr1 & TIM_CR1_DIR) ? 1 : 0);
683 }
684 
685 static const struct iio_enum stm32_count_direction_enum = {
686 	.items = stm32_count_direction_states,
687 	.num_items = ARRAY_SIZE(stm32_count_direction_states),
688 	.set = stm32_set_count_direction,
689 	.get = stm32_get_count_direction
690 };
691 
692 static ssize_t stm32_count_get_preset(struct iio_dev *indio_dev,
693 				      uintptr_t private,
694 				      const struct iio_chan_spec *chan,
695 				      char *buf)
696 {
697 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
698 	u32 arr;
699 
700 	regmap_read(priv->regmap, TIM_ARR, &arr);
701 
702 	return snprintf(buf, PAGE_SIZE, "%u\n", arr);
703 }
704 
705 static ssize_t stm32_count_set_preset(struct iio_dev *indio_dev,
706 				      uintptr_t private,
707 				      const struct iio_chan_spec *chan,
708 				      const char *buf, size_t len)
709 {
710 	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
711 	unsigned int preset;
712 	int ret;
713 
714 	ret = kstrtouint(buf, 0, &preset);
715 	if (ret)
716 		return ret;
717 
718 	regmap_write(priv->regmap, TIM_ARR, preset);
719 	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, TIM_CR1_ARPE);
720 
721 	return len;
722 }
723 
724 static const struct iio_chan_spec_ext_info stm32_trigger_count_info[] = {
725 	{
726 		.name = "preset",
727 		.shared = IIO_SEPARATE,
728 		.read = stm32_count_get_preset,
729 		.write = stm32_count_set_preset
730 	},
731 	IIO_ENUM("count_direction", IIO_SEPARATE, &stm32_count_direction_enum),
732 	IIO_ENUM_AVAILABLE("count_direction", &stm32_count_direction_enum),
733 	IIO_ENUM("quadrature_mode", IIO_SEPARATE, &stm32_quadrature_mode_enum),
734 	IIO_ENUM_AVAILABLE("quadrature_mode", &stm32_quadrature_mode_enum),
735 	IIO_ENUM("enable_mode", IIO_SEPARATE, &stm32_enable_mode_enum),
736 	IIO_ENUM_AVAILABLE("enable_mode", &stm32_enable_mode_enum),
737 	IIO_ENUM("trigger_mode", IIO_SEPARATE, &stm32_trigger_mode_enum),
738 	IIO_ENUM_AVAILABLE("trigger_mode", &stm32_trigger_mode_enum),
739 	{}
740 };
741 
742 static const struct iio_chan_spec stm32_trigger_channel = {
743 	.type = IIO_COUNT,
744 	.channel = 0,
745 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
746 			      BIT(IIO_CHAN_INFO_ENABLE) |
747 			      BIT(IIO_CHAN_INFO_SCALE),
748 	.ext_info = stm32_trigger_count_info,
749 	.indexed = 1
750 };
751 
752 static struct stm32_timer_trigger *stm32_setup_counter_device(struct device *dev)
753 {
754 	struct iio_dev *indio_dev;
755 	int ret;
756 
757 	indio_dev = devm_iio_device_alloc(dev,
758 					  sizeof(struct stm32_timer_trigger));
759 	if (!indio_dev)
760 		return NULL;
761 
762 	indio_dev->name = dev_name(dev);
763 	indio_dev->dev.parent = dev;
764 	indio_dev->info = &stm32_trigger_info;
765 	indio_dev->modes = INDIO_HARDWARE_TRIGGERED;
766 	indio_dev->num_channels = 1;
767 	indio_dev->channels = &stm32_trigger_channel;
768 	indio_dev->dev.of_node = dev->of_node;
769 
770 	ret = devm_iio_device_register(dev, indio_dev);
771 	if (ret)
772 		return NULL;
773 
774 	return iio_priv(indio_dev);
775 }
776 
777 /**
778  * is_stm32_timer_trigger
779  * @trig: trigger to be checked
780  *
781  * return true if the trigger is a valid stm32 iio timer trigger
782  * either return false
783  */
784 bool is_stm32_timer_trigger(struct iio_trigger *trig)
785 {
786 	return (trig->ops == &timer_trigger_ops);
787 }
788 EXPORT_SYMBOL(is_stm32_timer_trigger);
789 
790 static void stm32_timer_detect_trgo2(struct stm32_timer_trigger *priv)
791 {
792 	u32 val;
793 
794 	/*
795 	 * Master mode selection 2 bits can only be written and read back when
796 	 * timer supports it.
797 	 */
798 	regmap_update_bits(priv->regmap, TIM_CR2, TIM_CR2_MMS2, TIM_CR2_MMS2);
799 	regmap_read(priv->regmap, TIM_CR2, &val);
800 	regmap_update_bits(priv->regmap, TIM_CR2, TIM_CR2_MMS2, 0);
801 	priv->has_trgo2 = !!val;
802 }
803 
804 static int stm32_timer_trigger_probe(struct platform_device *pdev)
805 {
806 	struct device *dev = &pdev->dev;
807 	struct stm32_timer_trigger *priv;
808 	struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent);
809 	const struct stm32_timer_trigger_cfg *cfg;
810 	unsigned int index;
811 	int ret;
812 
813 	if (of_property_read_u32(dev->of_node, "reg", &index))
814 		return -EINVAL;
815 
816 	cfg = (const struct stm32_timer_trigger_cfg *)
817 		of_match_device(dev->driver->of_match_table, dev)->data;
818 
819 	if (index >= ARRAY_SIZE(triggers_table) ||
820 	    index >= cfg->num_valids_table)
821 		return -EINVAL;
822 
823 	/* Create an IIO device only if we have triggers to be validated */
824 	if (*cfg->valids_table[index])
825 		priv = stm32_setup_counter_device(dev);
826 	else
827 		priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
828 
829 	if (!priv)
830 		return -ENOMEM;
831 
832 	priv->dev = dev;
833 	priv->regmap = ddata->regmap;
834 	priv->clk = ddata->clk;
835 	priv->max_arr = ddata->max_arr;
836 	priv->triggers = triggers_table[index];
837 	priv->valids = cfg->valids_table[index];
838 	stm32_timer_detect_trgo2(priv);
839 
840 	ret = stm32_setup_iio_triggers(priv);
841 	if (ret)
842 		return ret;
843 
844 	platform_set_drvdata(pdev, priv);
845 
846 	return 0;
847 }
848 
849 static const struct stm32_timer_trigger_cfg stm32_timer_trg_cfg = {
850 	.valids_table = valids_table,
851 	.num_valids_table = ARRAY_SIZE(valids_table),
852 };
853 
854 static const struct stm32_timer_trigger_cfg stm32h7_timer_trg_cfg = {
855 	.valids_table = stm32h7_valids_table,
856 	.num_valids_table = ARRAY_SIZE(stm32h7_valids_table),
857 };
858 
859 static const struct of_device_id stm32_trig_of_match[] = {
860 	{
861 		.compatible = "st,stm32-timer-trigger",
862 		.data = (void *)&stm32_timer_trg_cfg,
863 	}, {
864 		.compatible = "st,stm32h7-timer-trigger",
865 		.data = (void *)&stm32h7_timer_trg_cfg,
866 	},
867 	{ /* end node */ },
868 };
869 MODULE_DEVICE_TABLE(of, stm32_trig_of_match);
870 
871 static struct platform_driver stm32_timer_trigger_driver = {
872 	.probe = stm32_timer_trigger_probe,
873 	.driver = {
874 		.name = "stm32-timer-trigger",
875 		.of_match_table = stm32_trig_of_match,
876 	},
877 };
878 module_platform_driver(stm32_timer_trigger_driver);
879 
880 MODULE_ALIAS("platform: stm32-timer-trigger");
881 MODULE_DESCRIPTION("STMicroelectronics STM32 Timer Trigger driver");
882 MODULE_LICENSE("GPL v2");
883