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/pinctrl/consumer.h>
16 #include <linux/platform_device.h>
17 #include <linux/pwm.h>
18
19 #define CCMR_CHANNEL_SHIFT 8
20 #define CCMR_CHANNEL_MASK 0xFF
21 #define MAX_BREAKINPUT 2
22
23 struct stm32_breakinput {
24 u32 index;
25 u32 level;
26 u32 filter;
27 };
28
29 struct stm32_pwm {
30 struct mutex lock; /* protect pwm config/enable */
31 struct clk *clk;
32 struct regmap *regmap;
33 u32 max_arr;
34 bool have_complementary_output;
35 struct stm32_breakinput breakinputs[MAX_BREAKINPUT];
36 unsigned int num_breakinputs;
37 u32 capture[4] ____cacheline_aligned; /* DMA'able buffer */
38 };
39
to_stm32_pwm_dev(struct pwm_chip * chip)40 static inline struct stm32_pwm *to_stm32_pwm_dev(struct pwm_chip *chip)
41 {
42 return pwmchip_get_drvdata(chip);
43 }
44
active_channels(struct stm32_pwm * dev)45 static u32 active_channels(struct stm32_pwm *dev)
46 {
47 u32 ccer;
48
49 regmap_read(dev->regmap, TIM_CCER, &ccer);
50
51 return ccer & TIM_CCER_CCXE;
52 }
53
54 struct stm32_pwm_waveform {
55 u32 ccer;
56 u32 psc;
57 u32 arr;
58 u32 ccr;
59 };
60
stm32_pwm_round_waveform_tohw(struct pwm_chip * chip,struct pwm_device * pwm,const struct pwm_waveform * wf,void * _wfhw)61 static int stm32_pwm_round_waveform_tohw(struct pwm_chip *chip,
62 struct pwm_device *pwm,
63 const struct pwm_waveform *wf,
64 void *_wfhw)
65 {
66 struct stm32_pwm_waveform *wfhw = _wfhw;
67 struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
68 unsigned int ch = pwm->hwpwm;
69 unsigned long rate;
70 u64 ccr, duty;
71 int ret;
72
73 if (wf->period_length_ns == 0) {
74 *wfhw = (struct stm32_pwm_waveform){
75 .ccer = 0,
76 };
77
78 return 0;
79 }
80
81 ret = clk_enable(priv->clk);
82 if (ret)
83 return ret;
84
85 wfhw->ccer = TIM_CCER_CCxE(ch + 1);
86 if (priv->have_complementary_output)
87 wfhw->ccer |= TIM_CCER_CCxNE(ch + 1);
88
89 rate = clk_get_rate(priv->clk);
90
91 if (active_channels(priv) & ~(1 << ch * 4)) {
92 u64 arr;
93
94 /*
95 * Other channels are already enabled, so the configured PSC and
96 * ARR must be used for this channel, too.
97 */
98 ret = regmap_read(priv->regmap, TIM_PSC, &wfhw->psc);
99 if (ret)
100 goto out;
101
102 ret = regmap_read(priv->regmap, TIM_ARR, &wfhw->arr);
103 if (ret)
104 goto out;
105
106 arr = mul_u64_u64_div_u64(wf->period_length_ns, rate,
107 (u64)NSEC_PER_SEC * (wfhw->psc + 1));
108 if (arr <= wfhw->arr) {
109 /*
110 * requested period is smaller than the currently
111 * configured and unchangable period, report back the smallest
112 * possible period, i.e. the current state and return 1
113 * to indicate the wrong rounding direction.
114 */
115 ret = 1;
116 }
117
118 } else {
119 /*
120 * .probe() asserted that clk_get_rate() is not bigger than 1 GHz, so
121 * the calculations here won't overflow.
122 * First we need to find the minimal value for prescaler such that
123 *
124 * period_ns * clkrate
125 * ------------------------------ < max_arr + 1
126 * NSEC_PER_SEC * (prescaler + 1)
127 *
128 * This equation is equivalent to
129 *
130 * period_ns * clkrate
131 * ---------------------------- < prescaler + 1
132 * NSEC_PER_SEC * (max_arr + 1)
133 *
134 * Using integer division and knowing that the right hand side is
135 * integer, this is further equivalent to
136 *
137 * (period_ns * clkrate) // (NSEC_PER_SEC * (max_arr + 1)) ≤ prescaler
138 */
139 u64 psc = mul_u64_u64_div_u64(wf->period_length_ns, rate,
140 (u64)NSEC_PER_SEC * ((u64)priv->max_arr + 1));
141 u64 arr;
142
143 wfhw->psc = min_t(u64, psc, MAX_TIM_PSC);
144
145 arr = mul_u64_u64_div_u64(wf->period_length_ns, rate,
146 (u64)NSEC_PER_SEC * (wfhw->psc + 1));
147 if (!arr) {
148 /*
149 * requested period is too small, report back the smallest
150 * possible period, i.e. ARR = 0. The only valid CCR
151 * value is then zero, too.
152 */
153 wfhw->arr = 0;
154 wfhw->ccr = 0;
155 ret = 1;
156 goto out;
157 }
158
159 /*
160 * ARR is limited intentionally to values less than
161 * priv->max_arr to allow 100% duty cycle.
162 */
163 wfhw->arr = min_t(u64, arr, priv->max_arr) - 1;
164 }
165
166 duty = mul_u64_u64_div_u64(wf->duty_length_ns, rate,
167 (u64)NSEC_PER_SEC * (wfhw->psc + 1));
168 duty = min_t(u64, duty, wfhw->arr + 1);
169
170 if (wf->duty_length_ns && wf->duty_offset_ns &&
171 wf->duty_length_ns + wf->duty_offset_ns >= wf->period_length_ns) {
172 wfhw->ccer |= TIM_CCER_CCxP(ch + 1);
173 if (priv->have_complementary_output)
174 wfhw->ccer |= TIM_CCER_CCxNP(ch + 1);
175
176 ccr = wfhw->arr + 1 - duty;
177 } else {
178 ccr = duty;
179 }
180
181 wfhw->ccr = min_t(u64, ccr, wfhw->arr + 1);
182
183 dev_dbg(&chip->dev, "pwm#%u: %lld/%lld [+%lld] @%lu -> CCER: %08x, PSC: %08x, ARR: %08x, CCR: %08x\n",
184 pwm->hwpwm, wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns,
185 rate, wfhw->ccer, wfhw->psc, wfhw->arr, wfhw->ccr);
186
187 out:
188 clk_disable(priv->clk);
189
190 return ret;
191 }
192
193 /*
194 * This should be moved to lib/math/div64.c. Currently there are some changes
195 * pending to mul_u64_u64_div_u64. Uwe will care for that when the dust settles.
196 */
stm32_pwm_mul_u64_u64_div_u64_roundup(u64 a,u64 b,u64 c)197 static u64 stm32_pwm_mul_u64_u64_div_u64_roundup(u64 a, u64 b, u64 c)
198 {
199 u64 res = mul_u64_u64_div_u64(a, b, c);
200 /* Those multiplications might overflow but it doesn't matter */
201 u64 rem = a * b - c * res;
202
203 if (rem)
204 res += 1;
205
206 return res;
207 }
208
stm32_pwm_round_waveform_fromhw(struct pwm_chip * chip,struct pwm_device * pwm,const void * _wfhw,struct pwm_waveform * wf)209 static int stm32_pwm_round_waveform_fromhw(struct pwm_chip *chip,
210 struct pwm_device *pwm,
211 const void *_wfhw,
212 struct pwm_waveform *wf)
213 {
214 const struct stm32_pwm_waveform *wfhw = _wfhw;
215 struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
216 unsigned int ch = pwm->hwpwm;
217
218 if (wfhw->ccer & TIM_CCER_CCxE(ch + 1)) {
219 unsigned long rate = clk_get_rate(priv->clk);
220 u64 ccr_ns;
221
222 /* The result doesn't overflow for rate >= 15259 */
223 wf->period_length_ns = stm32_pwm_mul_u64_u64_div_u64_roundup(((u64)wfhw->psc + 1) * (wfhw->arr + 1),
224 NSEC_PER_SEC, rate);
225
226 ccr_ns = stm32_pwm_mul_u64_u64_div_u64_roundup(((u64)wfhw->psc + 1) * wfhw->ccr,
227 NSEC_PER_SEC, rate);
228
229 if (wfhw->ccer & TIM_CCER_CCxP(ch + 1)) {
230 wf->duty_length_ns =
231 stm32_pwm_mul_u64_u64_div_u64_roundup(((u64)wfhw->psc + 1) * (wfhw->arr + 1 - wfhw->ccr),
232 NSEC_PER_SEC, rate);
233
234 wf->duty_offset_ns = ccr_ns;
235 } else {
236 wf->duty_length_ns = ccr_ns;
237 wf->duty_offset_ns = 0;
238 }
239
240 dev_dbg(&chip->dev, "pwm#%u: CCER: %08x, PSC: %08x, ARR: %08x, CCR: %08x @%lu -> %lld/%lld [+%lld]\n",
241 pwm->hwpwm, wfhw->ccer, wfhw->psc, wfhw->arr, wfhw->ccr, rate,
242 wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns);
243
244 } else {
245 *wf = (struct pwm_waveform){
246 .period_length_ns = 0,
247 };
248 }
249
250 return 0;
251 }
252
stm32_pwm_read_waveform(struct pwm_chip * chip,struct pwm_device * pwm,void * _wfhw)253 static int stm32_pwm_read_waveform(struct pwm_chip *chip,
254 struct pwm_device *pwm,
255 void *_wfhw)
256 {
257 struct stm32_pwm_waveform *wfhw = _wfhw;
258 struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
259 unsigned int ch = pwm->hwpwm;
260 int ret;
261
262 ret = clk_enable(priv->clk);
263 if (ret)
264 return ret;
265
266 ret = regmap_read(priv->regmap, TIM_CCER, &wfhw->ccer);
267 if (ret)
268 goto out;
269
270 if (wfhw->ccer & TIM_CCER_CCxE(ch + 1)) {
271 ret = regmap_read(priv->regmap, TIM_PSC, &wfhw->psc);
272 if (ret)
273 goto out;
274
275 ret = regmap_read(priv->regmap, TIM_ARR, &wfhw->arr);
276 if (ret)
277 goto out;
278
279 if (wfhw->arr == U32_MAX)
280 wfhw->arr -= 1;
281
282 ret = regmap_read(priv->regmap, TIM_CCRx(ch + 1), &wfhw->ccr);
283 if (ret)
284 goto out;
285
286 if (wfhw->ccr > wfhw->arr + 1)
287 wfhw->ccr = wfhw->arr + 1;
288 }
289
290 out:
291 clk_disable(priv->clk);
292
293 return ret;
294 }
295
stm32_pwm_write_waveform(struct pwm_chip * chip,struct pwm_device * pwm,const void * _wfhw)296 static int stm32_pwm_write_waveform(struct pwm_chip *chip,
297 struct pwm_device *pwm,
298 const void *_wfhw)
299 {
300 const struct stm32_pwm_waveform *wfhw = _wfhw;
301 struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
302 unsigned int ch = pwm->hwpwm;
303 int ret;
304
305 ret = clk_enable(priv->clk);
306 if (ret)
307 return ret;
308
309 if (wfhw->ccer & TIM_CCER_CCxE(ch + 1)) {
310 u32 ccer, mask;
311 unsigned int shift;
312 u32 ccmr;
313
314 ret = regmap_read(priv->regmap, TIM_CCER, &ccer);
315 if (ret)
316 goto out;
317
318 /* If there are other channels enabled, don't update PSC and ARR */
319 if (ccer & ~TIM_CCER_CCxE(ch + 1) & TIM_CCER_CCXE) {
320 u32 psc, arr;
321
322 ret = regmap_read(priv->regmap, TIM_PSC, &psc);
323 if (ret)
324 goto out;
325
326 if (psc != wfhw->psc) {
327 ret = -EBUSY;
328 goto out;
329 }
330
331 ret = regmap_read(priv->regmap, TIM_ARR, &arr);
332 if (ret)
333 goto out;
334
335 if (arr != wfhw->arr) {
336 ret = -EBUSY;
337 goto out;
338 }
339 } else {
340 ret = regmap_write(priv->regmap, TIM_PSC, wfhw->psc);
341 if (ret)
342 goto out;
343
344 ret = regmap_write(priv->regmap, TIM_ARR, wfhw->arr);
345 if (ret)
346 goto out;
347
348 ret = regmap_set_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE);
349 if (ret)
350 goto out;
351
352 }
353
354 /* set polarity */
355 mask = TIM_CCER_CCxP(ch + 1) | TIM_CCER_CCxNP(ch + 1);
356 ret = regmap_update_bits(priv->regmap, TIM_CCER, mask, wfhw->ccer);
357 if (ret)
358 goto out;
359
360 ret = regmap_write(priv->regmap, TIM_CCRx(ch + 1), wfhw->ccr);
361 if (ret)
362 goto out;
363
364 /* Configure output mode */
365 shift = (ch & 0x1) * CCMR_CHANNEL_SHIFT;
366 ccmr = (TIM_CCMR_PE | TIM_CCMR_M1) << shift;
367 mask = CCMR_CHANNEL_MASK << shift;
368
369 if (ch < 2)
370 ret = regmap_update_bits(priv->regmap, TIM_CCMR1, mask, ccmr);
371 else
372 ret = regmap_update_bits(priv->regmap, TIM_CCMR2, mask, ccmr);
373 if (ret)
374 goto out;
375
376 ret = regmap_set_bits(priv->regmap, TIM_BDTR, TIM_BDTR_MOE);
377 if (ret)
378 goto out;
379
380 if (!(ccer & TIM_CCER_CCxE(ch + 1))) {
381 mask = TIM_CCER_CCxE(ch + 1) | TIM_CCER_CCxNE(ch + 1);
382
383 ret = clk_enable(priv->clk);
384 if (ret)
385 goto out;
386
387 ccer = (ccer & ~mask) | (wfhw->ccer & mask);
388 regmap_write(priv->regmap, TIM_CCER, ccer);
389
390 /* Make sure that registers are updated */
391 regmap_set_bits(priv->regmap, TIM_EGR, TIM_EGR_UG);
392
393 /* Enable controller */
394 regmap_set_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN);
395 }
396
397 } else {
398 /* disable channel */
399 u32 mask, ccer;
400
401 mask = TIM_CCER_CCxE(ch + 1);
402 if (priv->have_complementary_output)
403 mask |= TIM_CCER_CCxNE(ch + 1);
404
405 ret = regmap_read(priv->regmap, TIM_CCER, &ccer);
406 if (ret)
407 goto out;
408
409 if (ccer & mask) {
410 ccer = ccer & ~mask;
411
412 ret = regmap_write(priv->regmap, TIM_CCER, ccer);
413 if (ret)
414 goto out;
415
416 if (!(ccer & TIM_CCER_CCXE)) {
417 /* When all channels are disabled, we can disable the controller */
418 ret = regmap_clear_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN);
419 if (ret)
420 goto out;
421 }
422
423 clk_disable(priv->clk);
424 }
425 }
426
427 out:
428 clk_disable(priv->clk);
429
430 return ret;
431 }
432
433 #define TIM_CCER_CC12P (TIM_CCER_CC1P | TIM_CCER_CC2P)
434 #define TIM_CCER_CC12E (TIM_CCER_CC1E | TIM_CCER_CC2E)
435 #define TIM_CCER_CC34P (TIM_CCER_CC3P | TIM_CCER_CC4P)
436 #define TIM_CCER_CC34E (TIM_CCER_CC3E | TIM_CCER_CC4E)
437
438 /*
439 * Capture using PWM input mode:
440 * ___ ___
441 * TI[1, 2, 3 or 4]: ........._| |________|
442 * ^0 ^1 ^2
443 * . . .
444 * . . XXXXX
445 * . . XXXXX |
446 * . XXXXX . |
447 * XXXXX . . |
448 * COUNTER: ______XXXXX . . . |_XXX
449 * start^ . . . ^stop
450 * . . . .
451 * v v . v
452 * v
453 * CCR1/CCR3: tx..........t0...........t2
454 * CCR2/CCR4: tx..............t1.........
455 *
456 * DMA burst transfer: | |
457 * v v
458 * DMA buffer: { t0, tx } { t2, t1 }
459 * DMA done: ^
460 *
461 * 0: IC1/3 snapchot on rising edge: counter value -> CCR1/CCR3
462 * + DMA transfer CCR[1/3] & CCR[2/4] values (t0, tx: doesn't care)
463 * 1: IC2/4 snapchot on falling edge: counter value -> CCR2/CCR4
464 * 2: IC1/3 snapchot on rising edge: counter value -> CCR1/CCR3
465 * + DMA transfer CCR[1/3] & CCR[2/4] values (t2, t1)
466 *
467 * DMA done, compute:
468 * - Period = t2 - t0
469 * - Duty cycle = t1 - t0
470 */
stm32_pwm_raw_capture(struct pwm_chip * chip,struct pwm_device * pwm,unsigned long tmo_ms,u32 * raw_prd,u32 * raw_dty)471 static int stm32_pwm_raw_capture(struct pwm_chip *chip, struct pwm_device *pwm,
472 unsigned long tmo_ms, u32 *raw_prd,
473 u32 *raw_dty)
474 {
475 struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
476 struct device *parent = pwmchip_parent(chip)->parent;
477 enum stm32_timers_dmas dma_id;
478 u32 ccen, ccr;
479 int ret;
480
481 /* Ensure registers have been updated, enable counter and capture */
482 regmap_set_bits(priv->regmap, TIM_EGR, TIM_EGR_UG);
483 regmap_set_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN);
484
485 /* Use cc1 or cc3 DMA resp for PWM input channels 1 & 2 or 3 & 4 */
486 dma_id = pwm->hwpwm < 2 ? STM32_TIMERS_DMA_CH1 : STM32_TIMERS_DMA_CH3;
487 ccen = pwm->hwpwm < 2 ? TIM_CCER_CC12E : TIM_CCER_CC34E;
488 ccr = pwm->hwpwm < 2 ? TIM_CCR1 : TIM_CCR3;
489 regmap_set_bits(priv->regmap, TIM_CCER, ccen);
490
491 /*
492 * Timer DMA burst mode. Request 2 registers, 2 bursts, to get both
493 * CCR1 & CCR2 (or CCR3 & CCR4) on each capture event.
494 * We'll get two capture snapchots: { CCR1, CCR2 }, { CCR1, CCR2 }
495 * or { CCR3, CCR4 }, { CCR3, CCR4 }
496 */
497 ret = stm32_timers_dma_burst_read(parent, priv->capture, dma_id, ccr, 2,
498 2, tmo_ms);
499 if (ret)
500 goto stop;
501
502 /* Period: t2 - t0 (take care of counter overflow) */
503 if (priv->capture[0] <= priv->capture[2])
504 *raw_prd = priv->capture[2] - priv->capture[0];
505 else
506 *raw_prd = priv->max_arr - priv->capture[0] + priv->capture[2];
507
508 /* Duty cycle capture requires at least two capture units */
509 if (pwm->chip->npwm < 2)
510 *raw_dty = 0;
511 else if (priv->capture[0] <= priv->capture[3])
512 *raw_dty = priv->capture[3] - priv->capture[0];
513 else
514 *raw_dty = priv->max_arr - priv->capture[0] + priv->capture[3];
515
516 if (*raw_dty > *raw_prd) {
517 /*
518 * Race beetween PWM input and DMA: it may happen
519 * falling edge triggers new capture on TI2/4 before DMA
520 * had a chance to read CCR2/4. It means capture[1]
521 * contains period + duty_cycle. So, subtract period.
522 */
523 *raw_dty -= *raw_prd;
524 }
525
526 stop:
527 regmap_clear_bits(priv->regmap, TIM_CCER, ccen);
528 regmap_clear_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN);
529
530 return ret;
531 }
532
stm32_pwm_capture(struct pwm_chip * chip,struct pwm_device * pwm,struct pwm_capture * result,unsigned long tmo_ms)533 static int stm32_pwm_capture(struct pwm_chip *chip, struct pwm_device *pwm,
534 struct pwm_capture *result, unsigned long tmo_ms)
535 {
536 struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
537 unsigned long long prd, div, dty;
538 unsigned long rate;
539 unsigned int psc = 0, icpsc, scale;
540 u32 raw_prd = 0, raw_dty = 0;
541 int ret = 0;
542
543 mutex_lock(&priv->lock);
544
545 if (active_channels(priv)) {
546 ret = -EBUSY;
547 goto unlock;
548 }
549
550 ret = clk_enable(priv->clk);
551 if (ret) {
552 dev_err(pwmchip_parent(chip), "failed to enable counter clock\n");
553 goto unlock;
554 }
555
556 rate = clk_get_rate(priv->clk);
557 if (!rate) {
558 ret = -EINVAL;
559 goto clk_dis;
560 }
561
562 /* prescaler: fit timeout window provided by upper layer */
563 div = (unsigned long long)rate * (unsigned long long)tmo_ms;
564 do_div(div, MSEC_PER_SEC);
565 prd = div;
566 while ((div > priv->max_arr) && (psc < MAX_TIM_PSC)) {
567 psc++;
568 div = prd;
569 do_div(div, psc + 1);
570 }
571 regmap_write(priv->regmap, TIM_ARR, priv->max_arr);
572 regmap_write(priv->regmap, TIM_PSC, psc);
573
574 /* Reset input selector to its default input and disable slave mode */
575 regmap_write(priv->regmap, TIM_TISEL, 0x0);
576 regmap_write(priv->regmap, TIM_SMCR, 0x0);
577
578 /* Map TI1 or TI2 PWM input to IC1 & IC2 (or TI3/4 to IC3 & IC4) */
579 regmap_update_bits(priv->regmap,
580 pwm->hwpwm < 2 ? TIM_CCMR1 : TIM_CCMR2,
581 TIM_CCMR_CC1S | TIM_CCMR_CC2S, pwm->hwpwm & 0x1 ?
582 TIM_CCMR_CC1S_TI2 | TIM_CCMR_CC2S_TI2 :
583 TIM_CCMR_CC1S_TI1 | TIM_CCMR_CC2S_TI1);
584
585 /* Capture period on IC1/3 rising edge, duty cycle on IC2/4 falling. */
586 regmap_update_bits(priv->regmap, TIM_CCER, pwm->hwpwm < 2 ?
587 TIM_CCER_CC12P : TIM_CCER_CC34P, pwm->hwpwm < 2 ?
588 TIM_CCER_CC2P : TIM_CCER_CC4P);
589
590 ret = stm32_pwm_raw_capture(chip, pwm, tmo_ms, &raw_prd, &raw_dty);
591 if (ret)
592 goto stop;
593
594 /*
595 * Got a capture. Try to improve accuracy at high rates:
596 * - decrease counter clock prescaler, scale up to max rate.
597 * - use input prescaler, capture once every /2 /4 or /8 edges.
598 */
599 if (raw_prd) {
600 u32 max_arr = priv->max_arr - 0x1000; /* arbitrary margin */
601
602 scale = max_arr / min(max_arr, raw_prd);
603 } else {
604 scale = priv->max_arr; /* below resolution, use max scale */
605 }
606
607 if (psc && scale > 1) {
608 /* 2nd measure with new scale */
609 psc /= scale;
610 regmap_write(priv->regmap, TIM_PSC, psc);
611 ret = stm32_pwm_raw_capture(chip, pwm, tmo_ms, &raw_prd,
612 &raw_dty);
613 if (ret)
614 goto stop;
615 }
616
617 /* Compute intermediate period not to exceed timeout at low rates */
618 prd = (unsigned long long)raw_prd * (psc + 1) * NSEC_PER_SEC;
619 do_div(prd, rate);
620
621 for (icpsc = 0; icpsc < MAX_TIM_ICPSC ; icpsc++) {
622 /* input prescaler: also keep arbitrary margin */
623 if (raw_prd >= (priv->max_arr - 0x1000) >> (icpsc + 1))
624 break;
625 if (prd >= (tmo_ms * NSEC_PER_MSEC) >> (icpsc + 2))
626 break;
627 }
628
629 if (!icpsc)
630 goto done;
631
632 /* Last chance to improve period accuracy, using input prescaler */
633 regmap_update_bits(priv->regmap,
634 pwm->hwpwm < 2 ? TIM_CCMR1 : TIM_CCMR2,
635 TIM_CCMR_IC1PSC | TIM_CCMR_IC2PSC,
636 FIELD_PREP(TIM_CCMR_IC1PSC, icpsc) |
637 FIELD_PREP(TIM_CCMR_IC2PSC, icpsc));
638
639 ret = stm32_pwm_raw_capture(chip, pwm, tmo_ms, &raw_prd, &raw_dty);
640 if (ret)
641 goto stop;
642
643 if (raw_dty >= (raw_prd >> icpsc)) {
644 /*
645 * We may fall here using input prescaler, when input
646 * capture starts on high side (before falling edge).
647 * Example with icpsc to capture on each 4 events:
648 *
649 * start 1st capture 2nd capture
650 * v v v
651 * ___ _____ _____ _____ _____ ____
652 * TI1..4 |__| |__| |__| |__| |__|
653 * v v . . . . . v v
654 * icpsc1/3: . 0 . 1 . 2 . 3 . 0
655 * icpsc2/4: 0 1 2 3 0
656 * v v v v
657 * CCR1/3 ......t0..............................t2
658 * CCR2/4 ..t1..............................t1'...
659 * . . .
660 * Capture0: .<----------------------------->.
661 * Capture1: .<-------------------------->. .
662 * . . .
663 * Period: .<------> . .
664 * Low side: .<>.
665 *
666 * Result:
667 * - Period = Capture0 / icpsc
668 * - Duty = Period - Low side = Period - (Capture0 - Capture1)
669 */
670 raw_dty = (raw_prd >> icpsc) - (raw_prd - raw_dty);
671 }
672
673 done:
674 prd = (unsigned long long)raw_prd * (psc + 1) * NSEC_PER_SEC;
675 result->period = DIV_ROUND_UP_ULL(prd, rate << icpsc);
676 dty = (unsigned long long)raw_dty * (psc + 1) * NSEC_PER_SEC;
677 result->duty_cycle = DIV_ROUND_UP_ULL(dty, rate);
678 stop:
679 regmap_write(priv->regmap, TIM_CCER, 0);
680 regmap_write(priv->regmap, pwm->hwpwm < 2 ? TIM_CCMR1 : TIM_CCMR2, 0);
681 regmap_write(priv->regmap, TIM_PSC, 0);
682 clk_dis:
683 clk_disable(priv->clk);
684 unlock:
685 mutex_unlock(&priv->lock);
686
687 return ret;
688 }
689
690 static const struct pwm_ops stm32pwm_ops = {
691 .sizeof_wfhw = sizeof(struct stm32_pwm_waveform),
692 .round_waveform_tohw = stm32_pwm_round_waveform_tohw,
693 .round_waveform_fromhw = stm32_pwm_round_waveform_fromhw,
694 .read_waveform = stm32_pwm_read_waveform,
695 .write_waveform = stm32_pwm_write_waveform,
696
697 .capture = IS_ENABLED(CONFIG_DMA_ENGINE) ? stm32_pwm_capture : NULL,
698 };
699
stm32_pwm_set_breakinput(struct stm32_pwm * priv,const struct stm32_breakinput * bi)700 static int stm32_pwm_set_breakinput(struct stm32_pwm *priv,
701 const struct stm32_breakinput *bi)
702 {
703 u32 shift = TIM_BDTR_BKF_SHIFT(bi->index);
704 u32 bke = TIM_BDTR_BKE(bi->index);
705 u32 bkp = TIM_BDTR_BKP(bi->index);
706 u32 bkf = TIM_BDTR_BKF(bi->index);
707 u32 mask = bkf | bkp | bke;
708 u32 bdtr;
709
710 bdtr = (bi->filter & TIM_BDTR_BKF_MASK) << shift | bke;
711
712 if (bi->level)
713 bdtr |= bkp;
714
715 regmap_update_bits(priv->regmap, TIM_BDTR, mask, bdtr);
716
717 regmap_read(priv->regmap, TIM_BDTR, &bdtr);
718
719 return (bdtr & bke) ? 0 : -EINVAL;
720 }
721
stm32_pwm_apply_breakinputs(struct stm32_pwm * priv)722 static int stm32_pwm_apply_breakinputs(struct stm32_pwm *priv)
723 {
724 unsigned int i;
725 int ret;
726
727 for (i = 0; i < priv->num_breakinputs; i++) {
728 ret = stm32_pwm_set_breakinput(priv, &priv->breakinputs[i]);
729 if (ret < 0)
730 return ret;
731 }
732
733 return 0;
734 }
735
stm32_pwm_probe_breakinputs(struct stm32_pwm * priv,struct device_node * np)736 static int stm32_pwm_probe_breakinputs(struct stm32_pwm *priv,
737 struct device_node *np)
738 {
739 int nb, ret, array_size;
740 unsigned int i;
741
742 nb = of_property_count_elems_of_size(np, "st,breakinput",
743 sizeof(struct stm32_breakinput));
744
745 /*
746 * Because "st,breakinput" parameter is optional do not make probe
747 * failed if it doesn't exist.
748 */
749 if (nb <= 0)
750 return 0;
751
752 if (nb > MAX_BREAKINPUT)
753 return -EINVAL;
754
755 priv->num_breakinputs = nb;
756 array_size = nb * sizeof(struct stm32_breakinput) / sizeof(u32);
757 ret = of_property_read_u32_array(np, "st,breakinput",
758 (u32 *)priv->breakinputs, array_size);
759 if (ret)
760 return ret;
761
762 for (i = 0; i < priv->num_breakinputs; i++) {
763 if (priv->breakinputs[i].index > 1 ||
764 priv->breakinputs[i].level > 1 ||
765 priv->breakinputs[i].filter > 15)
766 return -EINVAL;
767 }
768
769 return stm32_pwm_apply_breakinputs(priv);
770 }
771
stm32_pwm_detect_complementary(struct stm32_pwm * priv)772 static void stm32_pwm_detect_complementary(struct stm32_pwm *priv)
773 {
774 u32 ccer;
775
776 /*
777 * If complementary bit doesn't exist writing 1 will have no
778 * effect so we can detect it.
779 */
780 regmap_set_bits(priv->regmap, TIM_CCER, TIM_CCER_CC1NE);
781 regmap_read(priv->regmap, TIM_CCER, &ccer);
782 regmap_clear_bits(priv->regmap, TIM_CCER, TIM_CCER_CC1NE);
783
784 priv->have_complementary_output = (ccer != 0);
785 }
786
stm32_pwm_detect_channels(struct regmap * regmap,unsigned int * num_enabled)787 static unsigned int stm32_pwm_detect_channels(struct regmap *regmap,
788 unsigned int *num_enabled)
789 {
790 u32 ccer, ccer_backup;
791
792 /*
793 * If channels enable bits don't exist writing 1 will have no
794 * effect so we can detect and count them.
795 */
796 regmap_read(regmap, TIM_CCER, &ccer_backup);
797 regmap_set_bits(regmap, TIM_CCER, TIM_CCER_CCXE);
798 regmap_read(regmap, TIM_CCER, &ccer);
799 regmap_write(regmap, TIM_CCER, ccer_backup);
800
801 *num_enabled = hweight32(ccer_backup & TIM_CCER_CCXE);
802
803 return hweight32(ccer & TIM_CCER_CCXE);
804 }
805
stm32_pwm_probe(struct platform_device * pdev)806 static int stm32_pwm_probe(struct platform_device *pdev)
807 {
808 struct device *dev = &pdev->dev;
809 struct device_node *np = dev->of_node;
810 struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent);
811 struct pwm_chip *chip;
812 struct stm32_pwm *priv;
813 unsigned int npwm, num_enabled;
814 unsigned int i;
815 int ret;
816
817 npwm = stm32_pwm_detect_channels(ddata->regmap, &num_enabled);
818
819 chip = devm_pwmchip_alloc(dev, npwm, sizeof(*priv));
820 if (IS_ERR(chip))
821 return PTR_ERR(chip);
822 priv = to_stm32_pwm_dev(chip);
823
824 mutex_init(&priv->lock);
825 priv->regmap = ddata->regmap;
826 priv->clk = ddata->clk;
827 priv->max_arr = ddata->max_arr;
828
829 if (!priv->regmap || !priv->clk)
830 return dev_err_probe(dev, -EINVAL, "Failed to get %s\n",
831 priv->regmap ? "clk" : "regmap");
832
833 ret = stm32_pwm_probe_breakinputs(priv, np);
834 if (ret)
835 return dev_err_probe(dev, ret,
836 "Failed to configure breakinputs\n");
837
838 stm32_pwm_detect_complementary(priv);
839
840 ret = devm_clk_rate_exclusive_get(dev, priv->clk);
841 if (ret)
842 return dev_err_probe(dev, ret, "Failed to lock clock\n");
843
844 /*
845 * With the clk running with not more than 1 GHz the calculations in
846 * .apply() won't overflow.
847 */
848 if (clk_get_rate(priv->clk) > 1000000000)
849 return dev_err_probe(dev, -EINVAL, "Clock freq too high (%lu)\n",
850 clk_get_rate(priv->clk));
851
852 chip->ops = &stm32pwm_ops;
853
854 /* Initialize clock refcount to number of enabled PWM channels. */
855 for (i = 0; i < num_enabled; i++) {
856 ret = clk_enable(priv->clk);
857 if (ret)
858 return ret;
859 }
860
861 ret = devm_pwmchip_add(dev, chip);
862 if (ret < 0)
863 return dev_err_probe(dev, ret,
864 "Failed to register pwmchip\n");
865
866 platform_set_drvdata(pdev, chip);
867
868 return 0;
869 }
870
stm32_pwm_suspend(struct device * dev)871 static int stm32_pwm_suspend(struct device *dev)
872 {
873 struct pwm_chip *chip = dev_get_drvdata(dev);
874 struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
875 unsigned int i;
876 u32 ccer, mask;
877
878 /* Look for active channels */
879 ccer = active_channels(priv);
880
881 for (i = 0; i < chip->npwm; i++) {
882 mask = TIM_CCER_CCxE(i + 1);
883 if (ccer & mask) {
884 dev_err(dev, "PWM %u still in use by consumer %s\n",
885 i, chip->pwms[i].label);
886 return -EBUSY;
887 }
888 }
889
890 return pinctrl_pm_select_sleep_state(dev);
891 }
892
stm32_pwm_resume(struct device * dev)893 static int stm32_pwm_resume(struct device *dev)
894 {
895 struct pwm_chip *chip = dev_get_drvdata(dev);
896 struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
897 int ret;
898
899 ret = pinctrl_pm_select_default_state(dev);
900 if (ret)
901 return ret;
902
903 /* restore breakinput registers that may have been lost in low power */
904 return stm32_pwm_apply_breakinputs(priv);
905 }
906
907 static DEFINE_SIMPLE_DEV_PM_OPS(stm32_pwm_pm_ops, stm32_pwm_suspend, stm32_pwm_resume);
908
909 static const struct of_device_id stm32_pwm_of_match[] = {
910 { .compatible = "st,stm32-pwm", },
911 { /* end node */ },
912 };
913 MODULE_DEVICE_TABLE(of, stm32_pwm_of_match);
914
915 static struct platform_driver stm32_pwm_driver = {
916 .probe = stm32_pwm_probe,
917 .driver = {
918 .name = "stm32-pwm",
919 .of_match_table = stm32_pwm_of_match,
920 .pm = pm_ptr(&stm32_pwm_pm_ops),
921 },
922 };
923 module_platform_driver(stm32_pwm_driver);
924
925 MODULE_ALIAS("platform:stm32-pwm");
926 MODULE_DESCRIPTION("STMicroelectronics STM32 PWM driver");
927 MODULE_LICENSE("GPL v2");
928