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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
23struct stm32_breakinput {
24 u32 index;
25 u32 level;
26 u32 filter;
27};
28
29struct 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
40static inline struct stm32_pwm *to_stm32_pwm_dev(struct pwm_chip *chip)
41{
42 return pwmchip_get_drvdata(chip);
43}
44
45static 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
54struct stm32_pwm_waveform {
55 u32 ccer;
56 u32 psc;
57 u32 arr;
58 u32 ccr;
59};
60
61static 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 /*
107 * calculate the best value for ARR for the given PSC, refuse if
108 * the resulting period gets bigger than the requested one.
109 */
110 arr = mul_u64_u64_div_u64(wf->period_length_ns, rate,
111 (u64)NSEC_PER_SEC * (wfhw->psc + 1));
112 if (arr <= wfhw->arr) {
113 /*
114 * requested period is small than the currently
115 * configured and unchangable period, report back the smallest
116 * possible period, i.e. the current state; Initialize
117 * ccr to anything valid.
118 */
119 wfhw->ccr = 0;
120 ret = 1;
121 goto out;
122 }
123
124 } else {
125 /*
126 * .probe() asserted that clk_get_rate() is not bigger than 1 GHz, so
127 * the calculations here won't overflow.
128 * First we need to find the minimal value for prescaler such that
129 *
130 * period_ns * clkrate
131 * ------------------------------ < max_arr + 1
132 * NSEC_PER_SEC * (prescaler + 1)
133 *
134 * This equation is equivalent to
135 *
136 * period_ns * clkrate
137 * ---------------------------- < prescaler + 1
138 * NSEC_PER_SEC * (max_arr + 1)
139 *
140 * Using integer division and knowing that the right hand side is
141 * integer, this is further equivalent to
142 *
143 * (period_ns * clkrate) // (NSEC_PER_SEC * (max_arr + 1)) ≤ prescaler
144 */
145 u64 psc = mul_u64_u64_div_u64(wf->period_length_ns, rate,
146 (u64)NSEC_PER_SEC * ((u64)priv->max_arr + 1));
147 u64 arr;
148
149 wfhw->psc = min_t(u64, psc, MAX_TIM_PSC);
150
151 arr = mul_u64_u64_div_u64(wf->period_length_ns, rate,
152 (u64)NSEC_PER_SEC * (wfhw->psc + 1));
153 if (!arr) {
154 /*
155 * requested period is too small, report back the smallest
156 * possible period, i.e. ARR = 0. The only valid CCR
157 * value is then zero, too.
158 */
159 wfhw->arr = 0;
160 wfhw->ccr = 0;
161 ret = 1;
162 goto out;
163 }
164
165 /*
166 * ARR is limited intentionally to values less than
167 * priv->max_arr to allow 100% duty cycle.
168 */
169 wfhw->arr = min_t(u64, arr, priv->max_arr) - 1;
170 }
171
172 duty = mul_u64_u64_div_u64(wf->duty_length_ns, rate,
173 (u64)NSEC_PER_SEC * (wfhw->psc + 1));
174 duty = min_t(u64, duty, wfhw->arr + 1);
175
176 if (wf->duty_length_ns && wf->duty_offset_ns &&
177 wf->duty_length_ns + wf->duty_offset_ns >= wf->period_length_ns) {
178 wfhw->ccer |= TIM_CCER_CCxP(ch + 1);
179 if (priv->have_complementary_output)
180 wfhw->ccer |= TIM_CCER_CCxNP(ch + 1);
181
182 ccr = wfhw->arr + 1 - duty;
183 } else {
184 ccr = duty;
185 }
186
187 wfhw->ccr = min_t(u64, ccr, wfhw->arr + 1);
188
189 dev_dbg(&chip->dev, "pwm#%u: %lld/%lld [+%lld] @%lu -> CCER: %08x, PSC: %08x, ARR: %08x, CCR: %08x\n",
190 pwm->hwpwm, wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns,
191 rate, wfhw->ccer, wfhw->psc, wfhw->arr, wfhw->ccr);
192
193out:
194 clk_disable(priv->clk);
195
196 return ret;
197}
198
199/*
200 * This should be moved to lib/math/div64.c. Currently there are some changes
201 * pending to mul_u64_u64_div_u64. Uwe will care for that when the dust settles.
202 */
203static u64 stm32_pwm_mul_u64_u64_div_u64_roundup(u64 a, u64 b, u64 c)
204{
205 u64 res = mul_u64_u64_div_u64(a, b, c);
206 /* Those multiplications might overflow but it doesn't matter */
207 u64 rem = a * b - c * res;
208
209 if (rem)
210 res += 1;
211
212 return res;
213}
214
215static int stm32_pwm_round_waveform_fromhw(struct pwm_chip *chip,
216 struct pwm_device *pwm,
217 const void *_wfhw,
218 struct pwm_waveform *wf)
219{
220 const struct stm32_pwm_waveform *wfhw = _wfhw;
221 struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
222 unsigned int ch = pwm->hwpwm;
223
224 if (wfhw->ccer & TIM_CCER_CCxE(ch + 1)) {
225 unsigned long rate = clk_get_rate(priv->clk);
226 u64 ccr_ns;
227
228 /* The result doesn't overflow for rate >= 15259 */
229 wf->period_length_ns = stm32_pwm_mul_u64_u64_div_u64_roundup(((u64)wfhw->psc + 1) * (wfhw->arr + 1),
230 NSEC_PER_SEC, rate);
231
232 ccr_ns = stm32_pwm_mul_u64_u64_div_u64_roundup(((u64)wfhw->psc + 1) * wfhw->ccr,
233 NSEC_PER_SEC, rate);
234
235 if (wfhw->ccer & TIM_CCER_CCxP(ch + 1)) {
236 wf->duty_length_ns =
237 stm32_pwm_mul_u64_u64_div_u64_roundup(((u64)wfhw->psc + 1) * (wfhw->arr + 1 - wfhw->ccr),
238 NSEC_PER_SEC, rate);
239
240 wf->duty_offset_ns = ccr_ns;
241 } else {
242 wf->duty_length_ns = ccr_ns;
243 wf->duty_offset_ns = 0;
244 }
245
246 dev_dbg(&chip->dev, "pwm#%u: CCER: %08x, PSC: %08x, ARR: %08x, CCR: %08x @%lu -> %lld/%lld [+%lld]\n",
247 pwm->hwpwm, wfhw->ccer, wfhw->psc, wfhw->arr, wfhw->ccr, rate,
248 wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns);
249
250 } else {
251 *wf = (struct pwm_waveform){
252 .period_length_ns = 0,
253 };
254 }
255
256 return 0;
257}
258
259static int stm32_pwm_read_waveform(struct pwm_chip *chip,
260 struct pwm_device *pwm,
261 void *_wfhw)
262{
263 struct stm32_pwm_waveform *wfhw = _wfhw;
264 struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
265 unsigned int ch = pwm->hwpwm;
266 int ret;
267
268 ret = clk_enable(priv->clk);
269 if (ret)
270 return ret;
271
272 ret = regmap_read(priv->regmap, TIM_CCER, &wfhw->ccer);
273 if (ret)
274 goto out;
275
276 if (wfhw->ccer & TIM_CCER_CCxE(ch + 1)) {
277 ret = regmap_read(priv->regmap, TIM_PSC, &wfhw->psc);
278 if (ret)
279 goto out;
280
281 ret = regmap_read(priv->regmap, TIM_ARR, &wfhw->arr);
282 if (ret)
283 goto out;
284
285 if (wfhw->arr == U32_MAX)
286 wfhw->arr -= 1;
287
288 ret = regmap_read(priv->regmap, TIM_CCRx(ch + 1), &wfhw->ccr);
289 if (ret)
290 goto out;
291
292 if (wfhw->ccr > wfhw->arr + 1)
293 wfhw->ccr = wfhw->arr + 1;
294 }
295
296out:
297 clk_disable(priv->clk);
298
299 return ret;
300}
301
302static int stm32_pwm_write_waveform(struct pwm_chip *chip,
303 struct pwm_device *pwm,
304 const void *_wfhw)
305{
306 const struct stm32_pwm_waveform *wfhw = _wfhw;
307 struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
308 unsigned int ch = pwm->hwpwm;
309 int ret;
310
311 ret = clk_enable(priv->clk);
312 if (ret)
313 return ret;
314
315 if (wfhw->ccer & TIM_CCER_CCxE(ch + 1)) {
316 u32 ccer, mask;
317 unsigned int shift;
318 u32 ccmr;
319
320 ret = regmap_read(priv->regmap, TIM_CCER, &ccer);
321 if (ret)
322 goto out;
323
324 /* If there are other channels enabled, don't update PSC and ARR */
325 if (ccer & ~TIM_CCER_CCxE(ch + 1) & TIM_CCER_CCXE) {
326 u32 psc, arr;
327
328 ret = regmap_read(priv->regmap, TIM_PSC, &psc);
329 if (ret)
330 goto out;
331
332 if (psc != wfhw->psc) {
333 ret = -EBUSY;
334 goto out;
335 }
336
337 ret = regmap_read(priv->regmap, TIM_ARR, &arr);
338 if (ret)
339 goto out;
340
341 if (arr != wfhw->arr) {
342 ret = -EBUSY;
343 goto out;
344 }
345 } else {
346 ret = regmap_write(priv->regmap, TIM_PSC, wfhw->psc);
347 if (ret)
348 goto out;
349
350 ret = regmap_write(priv->regmap, TIM_ARR, wfhw->arr);
351 if (ret)
352 goto out;
353
354 ret = regmap_set_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE);
355 if (ret)
356 goto out;
357
358 }
359
360 /* set polarity */
361 mask = TIM_CCER_CCxP(ch + 1) | TIM_CCER_CCxNP(ch + 1);
362 ret = regmap_update_bits(priv->regmap, TIM_CCER, mask, wfhw->ccer);
363 if (ret)
364 goto out;
365
366 ret = regmap_write(priv->regmap, TIM_CCRx(ch + 1), wfhw->ccr);
367 if (ret)
368 goto out;
369
370 /* Configure output mode */
371 shift = (ch & 0x1) * CCMR_CHANNEL_SHIFT;
372 ccmr = (TIM_CCMR_PE | TIM_CCMR_M1) << shift;
373 mask = CCMR_CHANNEL_MASK << shift;
374
375 if (ch < 2)
376 ret = regmap_update_bits(priv->regmap, TIM_CCMR1, mask, ccmr);
377 else
378 ret = regmap_update_bits(priv->regmap, TIM_CCMR2, mask, ccmr);
379 if (ret)
380 goto out;
381
382 ret = regmap_set_bits(priv->regmap, TIM_BDTR, TIM_BDTR_MOE);
383 if (ret)
384 goto out;
385
386 if (!(ccer & TIM_CCER_CCxE(ch + 1))) {
387 mask = TIM_CCER_CCxE(ch + 1) | TIM_CCER_CCxNE(ch + 1);
388
389 ret = clk_enable(priv->clk);
390 if (ret)
391 goto out;
392
393 ccer = (ccer & ~mask) | (wfhw->ccer & mask);
394 regmap_write(priv->regmap, TIM_CCER, ccer);
395
396 /* Make sure that registers are updated */
397 regmap_set_bits(priv->regmap, TIM_EGR, TIM_EGR_UG);
398
399 /* Enable controller */
400 regmap_set_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN);
401 }
402
403 } else {
404 /* disable channel */
405 u32 mask, ccer;
406
407 mask = TIM_CCER_CCxE(ch + 1);
408 if (priv->have_complementary_output)
409 mask |= TIM_CCER_CCxNE(ch + 1);
410
411 ret = regmap_read(priv->regmap, TIM_CCER, &ccer);
412 if (ret)
413 goto out;
414
415 if (ccer & mask) {
416 ccer = ccer & ~mask;
417
418 ret = regmap_write(priv->regmap, TIM_CCER, ccer);
419 if (ret)
420 goto out;
421
422 if (!(ccer & TIM_CCER_CCXE)) {
423 /* When all channels are disabled, we can disable the controller */
424 ret = regmap_clear_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN);
425 if (ret)
426 goto out;
427 }
428
429 clk_disable(priv->clk);
430 }
431 }
432
433out:
434 clk_disable(priv->clk);
435
436 return ret;
437}
438
439#define TIM_CCER_CC12P (TIM_CCER_CC1P | TIM_CCER_CC2P)
440#define TIM_CCER_CC12E (TIM_CCER_CC1E | TIM_CCER_CC2E)
441#define TIM_CCER_CC34P (TIM_CCER_CC3P | TIM_CCER_CC4P)
442#define TIM_CCER_CC34E (TIM_CCER_CC3E | TIM_CCER_CC4E)
443
444/*
445 * Capture using PWM input mode:
446 * ___ ___
447 * TI[1, 2, 3 or 4]: ........._| |________|
448 * ^0 ^1 ^2
449 * . . .
450 * . . XXXXX
451 * . . XXXXX |
452 * . XXXXX . |
453 * XXXXX . . |
454 * COUNTER: ______XXXXX . . . |_XXX
455 * start^ . . . ^stop
456 * . . . .
457 * v v . v
458 * v
459 * CCR1/CCR3: tx..........t0...........t2
460 * CCR2/CCR4: tx..............t1.........
461 *
462 * DMA burst transfer: | |
463 * v v
464 * DMA buffer: { t0, tx } { t2, t1 }
465 * DMA done: ^
466 *
467 * 0: IC1/3 snapchot on rising edge: counter value -> CCR1/CCR3
468 * + DMA transfer CCR[1/3] & CCR[2/4] values (t0, tx: doesn't care)
469 * 1: IC2/4 snapchot on falling edge: counter value -> CCR2/CCR4
470 * 2: IC1/3 snapchot on rising edge: counter value -> CCR1/CCR3
471 * + DMA transfer CCR[1/3] & CCR[2/4] values (t2, t1)
472 *
473 * DMA done, compute:
474 * - Period = t2 - t0
475 * - Duty cycle = t1 - t0
476 */
477static int stm32_pwm_raw_capture(struct pwm_chip *chip, struct pwm_device *pwm,
478 unsigned long tmo_ms, u32 *raw_prd,
479 u32 *raw_dty)
480{
481 struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
482 struct device *parent = pwmchip_parent(chip)->parent;
483 enum stm32_timers_dmas dma_id;
484 u32 ccen, ccr;
485 int ret;
486
487 /* Ensure registers have been updated, enable counter and capture */
488 regmap_set_bits(priv->regmap, TIM_EGR, TIM_EGR_UG);
489 regmap_set_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN);
490
491 /* Use cc1 or cc3 DMA resp for PWM input channels 1 & 2 or 3 & 4 */
492 dma_id = pwm->hwpwm < 2 ? STM32_TIMERS_DMA_CH1 : STM32_TIMERS_DMA_CH3;
493 ccen = pwm->hwpwm < 2 ? TIM_CCER_CC12E : TIM_CCER_CC34E;
494 ccr = pwm->hwpwm < 2 ? TIM_CCR1 : TIM_CCR3;
495 regmap_set_bits(priv->regmap, TIM_CCER, ccen);
496
497 /*
498 * Timer DMA burst mode. Request 2 registers, 2 bursts, to get both
499 * CCR1 & CCR2 (or CCR3 & CCR4) on each capture event.
500 * We'll get two capture snapchots: { CCR1, CCR2 }, { CCR1, CCR2 }
501 * or { CCR3, CCR4 }, { CCR3, CCR4 }
502 */
503 ret = stm32_timers_dma_burst_read(parent, priv->capture, dma_id, ccr, 2,
504 2, tmo_ms);
505 if (ret)
506 goto stop;
507
508 /* Period: t2 - t0 (take care of counter overflow) */
509 if (priv->capture[0] <= priv->capture[2])
510 *raw_prd = priv->capture[2] - priv->capture[0];
511 else
512 *raw_prd = priv->max_arr - priv->capture[0] + priv->capture[2];
513
514 /* Duty cycle capture requires at least two capture units */
515 if (pwm->chip->npwm < 2)
516 *raw_dty = 0;
517 else if (priv->capture[0] <= priv->capture[3])
518 *raw_dty = priv->capture[3] - priv->capture[0];
519 else
520 *raw_dty = priv->max_arr - priv->capture[0] + priv->capture[3];
521
522 if (*raw_dty > *raw_prd) {
523 /*
524 * Race beetween PWM input and DMA: it may happen
525 * falling edge triggers new capture on TI2/4 before DMA
526 * had a chance to read CCR2/4. It means capture[1]
527 * contains period + duty_cycle. So, subtract period.
528 */
529 *raw_dty -= *raw_prd;
530 }
531
532stop:
533 regmap_clear_bits(priv->regmap, TIM_CCER, ccen);
534 regmap_clear_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN);
535
536 return ret;
537}
538
539static int stm32_pwm_capture(struct pwm_chip *chip, struct pwm_device *pwm,
540 struct pwm_capture *result, unsigned long tmo_ms)
541{
542 struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
543 unsigned long long prd, div, dty;
544 unsigned long rate;
545 unsigned int psc = 0, icpsc, scale;
546 u32 raw_prd = 0, raw_dty = 0;
547 int ret = 0;
548
549 mutex_lock(&priv->lock);
550
551 if (active_channels(priv)) {
552 ret = -EBUSY;
553 goto unlock;
554 }
555
556 ret = clk_enable(priv->clk);
557 if (ret) {
558 dev_err(pwmchip_parent(chip), "failed to enable counter clock\n");
559 goto unlock;
560 }
561
562 rate = clk_get_rate(priv->clk);
563 if (!rate) {
564 ret = -EINVAL;
565 goto clk_dis;
566 }
567
568 /* prescaler: fit timeout window provided by upper layer */
569 div = (unsigned long long)rate * (unsigned long long)tmo_ms;
570 do_div(div, MSEC_PER_SEC);
571 prd = div;
572 while ((div > priv->max_arr) && (psc < MAX_TIM_PSC)) {
573 psc++;
574 div = prd;
575 do_div(div, psc + 1);
576 }
577 regmap_write(priv->regmap, TIM_ARR, priv->max_arr);
578 regmap_write(priv->regmap, TIM_PSC, psc);
579
580 /* Reset input selector to its default input and disable slave mode */
581 regmap_write(priv->regmap, TIM_TISEL, 0x0);
582 regmap_write(priv->regmap, TIM_SMCR, 0x0);
583
584 /* Map TI1 or TI2 PWM input to IC1 & IC2 (or TI3/4 to IC3 & IC4) */
585 regmap_update_bits(priv->regmap,
586 pwm->hwpwm < 2 ? TIM_CCMR1 : TIM_CCMR2,
587 TIM_CCMR_CC1S | TIM_CCMR_CC2S, pwm->hwpwm & 0x1 ?
588 TIM_CCMR_CC1S_TI2 | TIM_CCMR_CC2S_TI2 :
589 TIM_CCMR_CC1S_TI1 | TIM_CCMR_CC2S_TI1);
590
591 /* Capture period on IC1/3 rising edge, duty cycle on IC2/4 falling. */
592 regmap_update_bits(priv->regmap, TIM_CCER, pwm->hwpwm < 2 ?
593 TIM_CCER_CC12P : TIM_CCER_CC34P, pwm->hwpwm < 2 ?
594 TIM_CCER_CC2P : TIM_CCER_CC4P);
595
596 ret = stm32_pwm_raw_capture(chip, pwm, tmo_ms, &raw_prd, &raw_dty);
597 if (ret)
598 goto stop;
599
600 /*
601 * Got a capture. Try to improve accuracy at high rates:
602 * - decrease counter clock prescaler, scale up to max rate.
603 * - use input prescaler, capture once every /2 /4 or /8 edges.
604 */
605 if (raw_prd) {
606 u32 max_arr = priv->max_arr - 0x1000; /* arbitrary margin */
607
608 scale = max_arr / min(max_arr, raw_prd);
609 } else {
610 scale = priv->max_arr; /* below resolution, use max scale */
611 }
612
613 if (psc && scale > 1) {
614 /* 2nd measure with new scale */
615 psc /= scale;
616 regmap_write(priv->regmap, TIM_PSC, psc);
617 ret = stm32_pwm_raw_capture(chip, pwm, tmo_ms, &raw_prd,
618 &raw_dty);
619 if (ret)
620 goto stop;
621 }
622
623 /* Compute intermediate period not to exceed timeout at low rates */
624 prd = (unsigned long long)raw_prd * (psc + 1) * NSEC_PER_SEC;
625 do_div(prd, rate);
626
627 for (icpsc = 0; icpsc < MAX_TIM_ICPSC ; icpsc++) {
628 /* input prescaler: also keep arbitrary margin */
629 if (raw_prd >= (priv->max_arr - 0x1000) >> (icpsc + 1))
630 break;
631 if (prd >= (tmo_ms * NSEC_PER_MSEC) >> (icpsc + 2))
632 break;
633 }
634
635 if (!icpsc)
636 goto done;
637
638 /* Last chance to improve period accuracy, using input prescaler */
639 regmap_update_bits(priv->regmap,
640 pwm->hwpwm < 2 ? TIM_CCMR1 : TIM_CCMR2,
641 TIM_CCMR_IC1PSC | TIM_CCMR_IC2PSC,
642 FIELD_PREP(TIM_CCMR_IC1PSC, icpsc) |
643 FIELD_PREP(TIM_CCMR_IC2PSC, icpsc));
644
645 ret = stm32_pwm_raw_capture(chip, pwm, tmo_ms, &raw_prd, &raw_dty);
646 if (ret)
647 goto stop;
648
649 if (raw_dty >= (raw_prd >> icpsc)) {
650 /*
651 * We may fall here using input prescaler, when input
652 * capture starts on high side (before falling edge).
653 * Example with icpsc to capture on each 4 events:
654 *
655 * start 1st capture 2nd capture
656 * v v v
657 * ___ _____ _____ _____ _____ ____
658 * TI1..4 |__| |__| |__| |__| |__|
659 * v v . . . . . v v
660 * icpsc1/3: . 0 . 1 . 2 . 3 . 0
661 * icpsc2/4: 0 1 2 3 0
662 * v v v v
663 * CCR1/3 ......t0..............................t2
664 * CCR2/4 ..t1..............................t1'...
665 * . . .
666 * Capture0: .<----------------------------->.
667 * Capture1: .<-------------------------->. .
668 * . . .
669 * Period: .<------> . .
670 * Low side: .<>.
671 *
672 * Result:
673 * - Period = Capture0 / icpsc
674 * - Duty = Period - Low side = Period - (Capture0 - Capture1)
675 */
676 raw_dty = (raw_prd >> icpsc) - (raw_prd - raw_dty);
677 }
678
679done:
680 prd = (unsigned long long)raw_prd * (psc + 1) * NSEC_PER_SEC;
681 result->period = DIV_ROUND_UP_ULL(prd, rate << icpsc);
682 dty = (unsigned long long)raw_dty * (psc + 1) * NSEC_PER_SEC;
683 result->duty_cycle = DIV_ROUND_UP_ULL(dty, rate);
684stop:
685 regmap_write(priv->regmap, TIM_CCER, 0);
686 regmap_write(priv->regmap, pwm->hwpwm < 2 ? TIM_CCMR1 : TIM_CCMR2, 0);
687 regmap_write(priv->regmap, TIM_PSC, 0);
688clk_dis:
689 clk_disable(priv->clk);
690unlock:
691 mutex_unlock(&priv->lock);
692
693 return ret;
694}
695
696static const struct pwm_ops stm32pwm_ops = {
697 .sizeof_wfhw = sizeof(struct stm32_pwm_waveform),
698 .round_waveform_tohw = stm32_pwm_round_waveform_tohw,
699 .round_waveform_fromhw = stm32_pwm_round_waveform_fromhw,
700 .read_waveform = stm32_pwm_read_waveform,
701 .write_waveform = stm32_pwm_write_waveform,
702
703 .capture = IS_ENABLED(CONFIG_DMA_ENGINE) ? stm32_pwm_capture : NULL,
704};
705
706static int stm32_pwm_set_breakinput(struct stm32_pwm *priv,
707 const struct stm32_breakinput *bi)
708{
709 u32 shift = TIM_BDTR_BKF_SHIFT(bi->index);
710 u32 bke = TIM_BDTR_BKE(bi->index);
711 u32 bkp = TIM_BDTR_BKP(bi->index);
712 u32 bkf = TIM_BDTR_BKF(bi->index);
713 u32 mask = bkf | bkp | bke;
714 u32 bdtr;
715
716 bdtr = (bi->filter & TIM_BDTR_BKF_MASK) << shift | bke;
717
718 if (bi->level)
719 bdtr |= bkp;
720
721 regmap_update_bits(priv->regmap, TIM_BDTR, mask, bdtr);
722
723 regmap_read(priv->regmap, TIM_BDTR, &bdtr);
724
725 return (bdtr & bke) ? 0 : -EINVAL;
726}
727
728static int stm32_pwm_apply_breakinputs(struct stm32_pwm *priv)
729{
730 unsigned int i;
731 int ret;
732
733 for (i = 0; i < priv->num_breakinputs; i++) {
734 ret = stm32_pwm_set_breakinput(priv, &priv->breakinputs[i]);
735 if (ret < 0)
736 return ret;
737 }
738
739 return 0;
740}
741
742static int stm32_pwm_probe_breakinputs(struct stm32_pwm *priv,
743 struct device_node *np)
744{
745 int nb, ret, array_size;
746 unsigned int i;
747
748 nb = of_property_count_elems_of_size(np, "st,breakinput",
749 sizeof(struct stm32_breakinput));
750
751 /*
752 * Because "st,breakinput" parameter is optional do not make probe
753 * failed if it doesn't exist.
754 */
755 if (nb <= 0)
756 return 0;
757
758 if (nb > MAX_BREAKINPUT)
759 return -EINVAL;
760
761 priv->num_breakinputs = nb;
762 array_size = nb * sizeof(struct stm32_breakinput) / sizeof(u32);
763 ret = of_property_read_u32_array(np, "st,breakinput",
764 (u32 *)priv->breakinputs, array_size);
765 if (ret)
766 return ret;
767
768 for (i = 0; i < priv->num_breakinputs; i++) {
769 if (priv->breakinputs[i].index > 1 ||
770 priv->breakinputs[i].level > 1 ||
771 priv->breakinputs[i].filter > 15)
772 return -EINVAL;
773 }
774
775 return stm32_pwm_apply_breakinputs(priv);
776}
777
778static void stm32_pwm_detect_complementary(struct stm32_pwm *priv)
779{
780 u32 ccer;
781
782 /*
783 * If complementary bit doesn't exist writing 1 will have no
784 * effect so we can detect it.
785 */
786 regmap_set_bits(priv->regmap, TIM_CCER, TIM_CCER_CC1NE);
787 regmap_read(priv->regmap, TIM_CCER, &ccer);
788 regmap_clear_bits(priv->regmap, TIM_CCER, TIM_CCER_CC1NE);
789
790 priv->have_complementary_output = (ccer != 0);
791}
792
793static unsigned int stm32_pwm_detect_channels(struct regmap *regmap,
794 unsigned int *num_enabled)
795{
796 u32 ccer, ccer_backup;
797
798 /*
799 * If channels enable bits don't exist writing 1 will have no
800 * effect so we can detect and count them.
801 */
802 regmap_read(regmap, TIM_CCER, &ccer_backup);
803 regmap_set_bits(regmap, TIM_CCER, TIM_CCER_CCXE);
804 regmap_read(regmap, TIM_CCER, &ccer);
805 regmap_write(regmap, TIM_CCER, ccer_backup);
806
807 *num_enabled = hweight32(ccer_backup & TIM_CCER_CCXE);
808
809 return hweight32(ccer & TIM_CCER_CCXE);
810}
811
812static int stm32_pwm_probe(struct platform_device *pdev)
813{
814 struct device *dev = &pdev->dev;
815 struct device_node *np = dev->of_node;
816 struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent);
817 struct pwm_chip *chip;
818 struct stm32_pwm *priv;
819 unsigned int npwm, num_enabled;
820 unsigned int i;
821 int ret;
822
823 npwm = stm32_pwm_detect_channels(ddata->regmap, &num_enabled);
824
825 chip = devm_pwmchip_alloc(dev, npwm, sizeof(*priv));
826 if (IS_ERR(chip))
827 return PTR_ERR(chip);
828 priv = to_stm32_pwm_dev(chip);
829
830 mutex_init(&priv->lock);
831 priv->regmap = ddata->regmap;
832 priv->clk = ddata->clk;
833 priv->max_arr = ddata->max_arr;
834
835 if (!priv->regmap || !priv->clk)
836 return dev_err_probe(dev, -EINVAL, "Failed to get %s\n",
837 priv->regmap ? "clk" : "regmap");
838
839 ret = stm32_pwm_probe_breakinputs(priv, np);
840 if (ret)
841 return dev_err_probe(dev, ret,
842 "Failed to configure breakinputs\n");
843
844 stm32_pwm_detect_complementary(priv);
845
846 ret = devm_clk_rate_exclusive_get(dev, priv->clk);
847 if (ret)
848 return dev_err_probe(dev, ret, "Failed to lock clock\n");
849
850 /*
851 * With the clk running with not more than 1 GHz the calculations in
852 * .apply() won't overflow.
853 */
854 if (clk_get_rate(priv->clk) > 1000000000)
855 return dev_err_probe(dev, -EINVAL, "Clock freq too high (%lu)\n",
856 clk_get_rate(priv->clk));
857
858 chip->ops = &stm32pwm_ops;
859
860 /* Initialize clock refcount to number of enabled PWM channels. */
861 for (i = 0; i < num_enabled; i++) {
862 ret = clk_enable(priv->clk);
863 if (ret)
864 return ret;
865 }
866
867 ret = devm_pwmchip_add(dev, chip);
868 if (ret < 0)
869 return dev_err_probe(dev, ret,
870 "Failed to register pwmchip\n");
871
872 platform_set_drvdata(pdev, chip);
873
874 return 0;
875}
876
877static int stm32_pwm_suspend(struct device *dev)
878{
879 struct pwm_chip *chip = dev_get_drvdata(dev);
880 struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
881 unsigned int i;
882 u32 ccer, mask;
883
884 /* Look for active channels */
885 ccer = active_channels(priv);
886
887 for (i = 0; i < chip->npwm; i++) {
888 mask = TIM_CCER_CCxE(i + 1);
889 if (ccer & mask) {
890 dev_err(dev, "PWM %u still in use by consumer %s\n",
891 i, chip->pwms[i].label);
892 return -EBUSY;
893 }
894 }
895
896 return pinctrl_pm_select_sleep_state(dev);
897}
898
899static int stm32_pwm_resume(struct device *dev)
900{
901 struct pwm_chip *chip = dev_get_drvdata(dev);
902 struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
903 int ret;
904
905 ret = pinctrl_pm_select_default_state(dev);
906 if (ret)
907 return ret;
908
909 /* restore breakinput registers that may have been lost in low power */
910 return stm32_pwm_apply_breakinputs(priv);
911}
912
913static DEFINE_SIMPLE_DEV_PM_OPS(stm32_pwm_pm_ops, stm32_pwm_suspend, stm32_pwm_resume);
914
915static const struct of_device_id stm32_pwm_of_match[] = {
916 { .compatible = "st,stm32-pwm", },
917 { /* end node */ },
918};
919MODULE_DEVICE_TABLE(of, stm32_pwm_of_match);
920
921static struct platform_driver stm32_pwm_driver = {
922 .probe = stm32_pwm_probe,
923 .driver = {
924 .name = "stm32-pwm",
925 .of_match_table = stm32_pwm_of_match,
926 .pm = pm_ptr(&stm32_pwm_pm_ops),
927 },
928};
929module_platform_driver(stm32_pwm_driver);
930
931MODULE_ALIAS("platform:stm32-pwm");
932MODULE_DESCRIPTION("STMicroelectronics STM32 PWM driver");
933MODULE_LICENSE("GPL v2");
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/mfd/stm32-timers.h>
12#include <linux/module.h>
13#include <linux/of.h>
14#include <linux/platform_device.h>
15#include <linux/pwm.h>
16
17#define CCMR_CHANNEL_SHIFT 8
18#define CCMR_CHANNEL_MASK 0xFF
19#define MAX_BREAKINPUT 2
20
21struct stm32_pwm {
22 struct pwm_chip chip;
23 struct mutex lock; /* protect pwm config/enable */
24 struct clk *clk;
25 struct regmap *regmap;
26 u32 max_arr;
27 bool have_complementary_output;
28};
29
30struct stm32_breakinput {
31 u32 index;
32 u32 level;
33 u32 filter;
34};
35
36static inline struct stm32_pwm *to_stm32_pwm_dev(struct pwm_chip *chip)
37{
38 return container_of(chip, struct stm32_pwm, chip);
39}
40
41static u32 active_channels(struct stm32_pwm *dev)
42{
43 u32 ccer;
44
45 regmap_read(dev->regmap, TIM_CCER, &ccer);
46
47 return ccer & TIM_CCER_CCXE;
48}
49
50static int write_ccrx(struct stm32_pwm *dev, int ch, u32 value)
51{
52 switch (ch) {
53 case 0:
54 return regmap_write(dev->regmap, TIM_CCR1, value);
55 case 1:
56 return regmap_write(dev->regmap, TIM_CCR2, value);
57 case 2:
58 return regmap_write(dev->regmap, TIM_CCR3, value);
59 case 3:
60 return regmap_write(dev->regmap, TIM_CCR4, value);
61 }
62 return -EINVAL;
63}
64
65static int stm32_pwm_config(struct stm32_pwm *priv, int ch,
66 int duty_ns, int period_ns)
67{
68 unsigned long long prd, div, dty;
69 unsigned int prescaler = 0;
70 u32 ccmr, mask, shift;
71
72 /* Period and prescaler values depends on clock rate */
73 div = (unsigned long long)clk_get_rate(priv->clk) * period_ns;
74
75 do_div(div, NSEC_PER_SEC);
76 prd = div;
77
78 while (div > priv->max_arr) {
79 prescaler++;
80 div = prd;
81 do_div(div, prescaler + 1);
82 }
83
84 prd = div;
85
86 if (prescaler > MAX_TIM_PSC)
87 return -EINVAL;
88
89 /*
90 * All channels share the same prescaler and counter so when two
91 * channels are active at the same time we can't change them
92 */
93 if (active_channels(priv) & ~(1 << ch * 4)) {
94 u32 psc, arr;
95
96 regmap_read(priv->regmap, TIM_PSC, &psc);
97 regmap_read(priv->regmap, TIM_ARR, &arr);
98
99 if ((psc != prescaler) || (arr != prd - 1))
100 return -EBUSY;
101 }
102
103 regmap_write(priv->regmap, TIM_PSC, prescaler);
104 regmap_write(priv->regmap, TIM_ARR, prd - 1);
105 regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, TIM_CR1_ARPE);
106
107 /* Calculate the duty cycles */
108 dty = prd * duty_ns;
109 do_div(dty, period_ns);
110
111 write_ccrx(priv, ch, dty);
112
113 /* Configure output mode */
114 shift = (ch & 0x1) * CCMR_CHANNEL_SHIFT;
115 ccmr = (TIM_CCMR_PE | TIM_CCMR_M1) << shift;
116 mask = CCMR_CHANNEL_MASK << shift;
117
118 if (ch < 2)
119 regmap_update_bits(priv->regmap, TIM_CCMR1, mask, ccmr);
120 else
121 regmap_update_bits(priv->regmap, TIM_CCMR2, mask, ccmr);
122
123 regmap_update_bits(priv->regmap, TIM_BDTR,
124 TIM_BDTR_MOE | TIM_BDTR_AOE,
125 TIM_BDTR_MOE | TIM_BDTR_AOE);
126
127 return 0;
128}
129
130static int stm32_pwm_set_polarity(struct stm32_pwm *priv, int ch,
131 enum pwm_polarity polarity)
132{
133 u32 mask;
134
135 mask = TIM_CCER_CC1P << (ch * 4);
136 if (priv->have_complementary_output)
137 mask |= TIM_CCER_CC1NP << (ch * 4);
138
139 regmap_update_bits(priv->regmap, TIM_CCER, mask,
140 polarity == PWM_POLARITY_NORMAL ? 0 : mask);
141
142 return 0;
143}
144
145static int stm32_pwm_enable(struct stm32_pwm *priv, int ch)
146{
147 u32 mask;
148 int ret;
149
150 ret = clk_enable(priv->clk);
151 if (ret)
152 return ret;
153
154 /* Enable channel */
155 mask = TIM_CCER_CC1E << (ch * 4);
156 if (priv->have_complementary_output)
157 mask |= TIM_CCER_CC1NE << (ch * 4);
158
159 regmap_update_bits(priv->regmap, TIM_CCER, mask, mask);
160
161 /* Make sure that registers are updated */
162 regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
163
164 /* Enable controller */
165 regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, TIM_CR1_CEN);
166
167 return 0;
168}
169
170static void stm32_pwm_disable(struct stm32_pwm *priv, int ch)
171{
172 u32 mask;
173
174 /* Disable channel */
175 mask = TIM_CCER_CC1E << (ch * 4);
176 if (priv->have_complementary_output)
177 mask |= TIM_CCER_CC1NE << (ch * 4);
178
179 regmap_update_bits(priv->regmap, TIM_CCER, mask, 0);
180
181 /* When all channels are disabled, we can disable the controller */
182 if (!active_channels(priv))
183 regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
184
185 clk_disable(priv->clk);
186}
187
188static int stm32_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
189 struct pwm_state *state)
190{
191 bool enabled;
192 struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
193 int ret;
194
195 enabled = pwm->state.enabled;
196
197 if (enabled && !state->enabled) {
198 stm32_pwm_disable(priv, pwm->hwpwm);
199 return 0;
200 }
201
202 if (state->polarity != pwm->state.polarity)
203 stm32_pwm_set_polarity(priv, pwm->hwpwm, state->polarity);
204
205 ret = stm32_pwm_config(priv, pwm->hwpwm,
206 state->duty_cycle, state->period);
207 if (ret)
208 return ret;
209
210 if (!enabled && state->enabled)
211 ret = stm32_pwm_enable(priv, pwm->hwpwm);
212
213 return ret;
214}
215
216static int stm32_pwm_apply_locked(struct pwm_chip *chip, struct pwm_device *pwm,
217 struct pwm_state *state)
218{
219 struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
220 int ret;
221
222 /* protect common prescaler for all active channels */
223 mutex_lock(&priv->lock);
224 ret = stm32_pwm_apply(chip, pwm, state);
225 mutex_unlock(&priv->lock);
226
227 return ret;
228}
229
230static const struct pwm_ops stm32pwm_ops = {
231 .owner = THIS_MODULE,
232 .apply = stm32_pwm_apply_locked,
233};
234
235static int stm32_pwm_set_breakinput(struct stm32_pwm *priv,
236 int index, int level, int filter)
237{
238 u32 bke = (index == 0) ? TIM_BDTR_BKE : TIM_BDTR_BK2E;
239 int shift = (index == 0) ? TIM_BDTR_BKF_SHIFT : TIM_BDTR_BK2F_SHIFT;
240 u32 mask = (index == 0) ? TIM_BDTR_BKE | TIM_BDTR_BKP | TIM_BDTR_BKF
241 : TIM_BDTR_BK2E | TIM_BDTR_BK2P | TIM_BDTR_BK2F;
242 u32 bdtr = bke;
243
244 /*
245 * The both bits could be set since only one will be wrote
246 * due to mask value.
247 */
248 if (level)
249 bdtr |= TIM_BDTR_BKP | TIM_BDTR_BK2P;
250
251 bdtr |= (filter & TIM_BDTR_BKF_MASK) << shift;
252
253 regmap_update_bits(priv->regmap, TIM_BDTR, mask, bdtr);
254
255 regmap_read(priv->regmap, TIM_BDTR, &bdtr);
256
257 return (bdtr & bke) ? 0 : -EINVAL;
258}
259
260static int stm32_pwm_apply_breakinputs(struct stm32_pwm *priv,
261 struct device_node *np)
262{
263 struct stm32_breakinput breakinput[MAX_BREAKINPUT];
264 int nb, ret, i, array_size;
265
266 nb = of_property_count_elems_of_size(np, "st,breakinput",
267 sizeof(struct stm32_breakinput));
268
269 /*
270 * Because "st,breakinput" parameter is optional do not make probe
271 * failed if it doesn't exist.
272 */
273 if (nb <= 0)
274 return 0;
275
276 if (nb > MAX_BREAKINPUT)
277 return -EINVAL;
278
279 array_size = nb * sizeof(struct stm32_breakinput) / sizeof(u32);
280 ret = of_property_read_u32_array(np, "st,breakinput",
281 (u32 *)breakinput, array_size);
282 if (ret)
283 return ret;
284
285 for (i = 0; i < nb && !ret; i++) {
286 ret = stm32_pwm_set_breakinput(priv,
287 breakinput[i].index,
288 breakinput[i].level,
289 breakinput[i].filter);
290 }
291
292 return ret;
293}
294
295static void stm32_pwm_detect_complementary(struct stm32_pwm *priv)
296{
297 u32 ccer;
298
299 /*
300 * If complementary bit doesn't exist writing 1 will have no
301 * effect so we can detect it.
302 */
303 regmap_update_bits(priv->regmap,
304 TIM_CCER, TIM_CCER_CC1NE, TIM_CCER_CC1NE);
305 regmap_read(priv->regmap, TIM_CCER, &ccer);
306 regmap_update_bits(priv->regmap, TIM_CCER, TIM_CCER_CC1NE, 0);
307
308 priv->have_complementary_output = (ccer != 0);
309}
310
311static int stm32_pwm_detect_channels(struct stm32_pwm *priv)
312{
313 u32 ccer;
314 int npwm = 0;
315
316 /*
317 * If channels enable bits don't exist writing 1 will have no
318 * effect so we can detect and count them.
319 */
320 regmap_update_bits(priv->regmap,
321 TIM_CCER, TIM_CCER_CCXE, TIM_CCER_CCXE);
322 regmap_read(priv->regmap, TIM_CCER, &ccer);
323 regmap_update_bits(priv->regmap, TIM_CCER, TIM_CCER_CCXE, 0);
324
325 if (ccer & TIM_CCER_CC1E)
326 npwm++;
327
328 if (ccer & TIM_CCER_CC2E)
329 npwm++;
330
331 if (ccer & TIM_CCER_CC3E)
332 npwm++;
333
334 if (ccer & TIM_CCER_CC4E)
335 npwm++;
336
337 return npwm;
338}
339
340static int stm32_pwm_probe(struct platform_device *pdev)
341{
342 struct device *dev = &pdev->dev;
343 struct device_node *np = dev->of_node;
344 struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent);
345 struct stm32_pwm *priv;
346 int ret;
347
348 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
349 if (!priv)
350 return -ENOMEM;
351
352 mutex_init(&priv->lock);
353 priv->regmap = ddata->regmap;
354 priv->clk = ddata->clk;
355 priv->max_arr = ddata->max_arr;
356
357 if (!priv->regmap || !priv->clk)
358 return -EINVAL;
359
360 ret = stm32_pwm_apply_breakinputs(priv, np);
361 if (ret)
362 return ret;
363
364 stm32_pwm_detect_complementary(priv);
365
366 priv->chip.base = -1;
367 priv->chip.dev = dev;
368 priv->chip.ops = &stm32pwm_ops;
369 priv->chip.npwm = stm32_pwm_detect_channels(priv);
370
371 ret = pwmchip_add(&priv->chip);
372 if (ret < 0)
373 return ret;
374
375 platform_set_drvdata(pdev, priv);
376
377 return 0;
378}
379
380static int stm32_pwm_remove(struct platform_device *pdev)
381{
382 struct stm32_pwm *priv = platform_get_drvdata(pdev);
383 unsigned int i;
384
385 for (i = 0; i < priv->chip.npwm; i++)
386 pwm_disable(&priv->chip.pwms[i]);
387
388 pwmchip_remove(&priv->chip);
389
390 return 0;
391}
392
393static const struct of_device_id stm32_pwm_of_match[] = {
394 { .compatible = "st,stm32-pwm", },
395 { /* end node */ },
396};
397MODULE_DEVICE_TABLE(of, stm32_pwm_of_match);
398
399static struct platform_driver stm32_pwm_driver = {
400 .probe = stm32_pwm_probe,
401 .remove = stm32_pwm_remove,
402 .driver = {
403 .name = "stm32-pwm",
404 .of_match_table = stm32_pwm_of_match,
405 },
406};
407module_platform_driver(stm32_pwm_driver);
408
409MODULE_ALIAS("platform:stm32-pwm");
410MODULE_DESCRIPTION("STMicroelectronics STM32 PWM driver");
411MODULE_LICENSE("GPL v2");