1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) Overkiz SAS 2012
4 *
5 * Author: Boris BREZILLON <b.brezillon@overkiz.com>
6 */
7
8 #include <linux/module.h>
9 #include <linux/init.h>
10 #include <linux/clocksource.h>
11 #include <linux/clockchips.h>
12 #include <linux/interrupt.h>
13 #include <linux/irq.h>
14
15 #include <linux/clk.h>
16 #include <linux/err.h>
17 #include <linux/ioport.h>
18 #include <linux/io.h>
19 #include <linux/mfd/syscon.h>
20 #include <linux/platform_device.h>
21 #include <linux/pwm.h>
22 #include <linux/of_device.h>
23 #include <linux/of_irq.h>
24 #include <linux/regmap.h>
25 #include <linux/slab.h>
26 #include <soc/at91/atmel_tcb.h>
27
28 #define NPWM 2
29
30 #define ATMEL_TC_ACMR_MASK (ATMEL_TC_ACPA | ATMEL_TC_ACPC | \
31 ATMEL_TC_AEEVT | ATMEL_TC_ASWTRG)
32
33 #define ATMEL_TC_BCMR_MASK (ATMEL_TC_BCPB | ATMEL_TC_BCPC | \
34 ATMEL_TC_BEEVT | ATMEL_TC_BSWTRG)
35
36 struct atmel_tcb_pwm_device {
37 enum pwm_polarity polarity; /* PWM polarity */
38 unsigned div; /* PWM clock divider */
39 unsigned duty; /* PWM duty expressed in clk cycles */
40 unsigned period; /* PWM period expressed in clk cycles */
41 };
42
43 struct atmel_tcb_channel {
44 u32 enabled;
45 u32 cmr;
46 u32 ra;
47 u32 rb;
48 u32 rc;
49 };
50
51 struct atmel_tcb_pwm_chip {
52 struct pwm_chip chip;
53 spinlock_t lock;
54 u8 channel;
55 u8 width;
56 struct regmap *regmap;
57 struct clk *clk;
58 struct clk *gclk;
59 struct clk *slow_clk;
60 struct atmel_tcb_pwm_device *pwms[NPWM];
61 struct atmel_tcb_channel bkup;
62 };
63
64 const u8 atmel_tcb_divisors[] = { 2, 8, 32, 128, 0, };
65
to_tcb_chip(struct pwm_chip * chip)66 static inline struct atmel_tcb_pwm_chip *to_tcb_chip(struct pwm_chip *chip)
67 {
68 return container_of(chip, struct atmel_tcb_pwm_chip, chip);
69 }
70
atmel_tcb_pwm_set_polarity(struct pwm_chip * chip,struct pwm_device * pwm,enum pwm_polarity polarity)71 static int atmel_tcb_pwm_set_polarity(struct pwm_chip *chip,
72 struct pwm_device *pwm,
73 enum pwm_polarity polarity)
74 {
75 struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);
76
77 tcbpwm->polarity = polarity;
78
79 return 0;
80 }
81
atmel_tcb_pwm_request(struct pwm_chip * chip,struct pwm_device * pwm)82 static int atmel_tcb_pwm_request(struct pwm_chip *chip,
83 struct pwm_device *pwm)
84 {
85 struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
86 struct atmel_tcb_pwm_device *tcbpwm;
87 unsigned cmr;
88 int ret;
89
90 tcbpwm = devm_kzalloc(chip->dev, sizeof(*tcbpwm), GFP_KERNEL);
91 if (!tcbpwm)
92 return -ENOMEM;
93
94 ret = clk_prepare_enable(tcbpwmc->clk);
95 if (ret) {
96 devm_kfree(chip->dev, tcbpwm);
97 return ret;
98 }
99
100 pwm_set_chip_data(pwm, tcbpwm);
101 tcbpwm->polarity = PWM_POLARITY_NORMAL;
102 tcbpwm->duty = 0;
103 tcbpwm->period = 0;
104 tcbpwm->div = 0;
105
106 spin_lock(&tcbpwmc->lock);
107 regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), &cmr);
108 /*
109 * Get init config from Timer Counter registers if
110 * Timer Counter is already configured as a PWM generator.
111 */
112 if (cmr & ATMEL_TC_WAVE) {
113 if (pwm->hwpwm == 0)
114 regmap_read(tcbpwmc->regmap,
115 ATMEL_TC_REG(tcbpwmc->channel, RA),
116 &tcbpwm->duty);
117 else
118 regmap_read(tcbpwmc->regmap,
119 ATMEL_TC_REG(tcbpwmc->channel, RB),
120 &tcbpwm->duty);
121
122 tcbpwm->div = cmr & ATMEL_TC_TCCLKS;
123 regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, RC),
124 &tcbpwm->period);
125 cmr &= (ATMEL_TC_TCCLKS | ATMEL_TC_ACMR_MASK |
126 ATMEL_TC_BCMR_MASK);
127 } else
128 cmr = 0;
129
130 cmr |= ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO | ATMEL_TC_EEVT_XC0;
131 regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), cmr);
132 spin_unlock(&tcbpwmc->lock);
133
134 tcbpwmc->pwms[pwm->hwpwm] = tcbpwm;
135
136 return 0;
137 }
138
atmel_tcb_pwm_free(struct pwm_chip * chip,struct pwm_device * pwm)139 static void atmel_tcb_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
140 {
141 struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
142 struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);
143
144 clk_disable_unprepare(tcbpwmc->clk);
145 tcbpwmc->pwms[pwm->hwpwm] = NULL;
146 devm_kfree(chip->dev, tcbpwm);
147 }
148
atmel_tcb_pwm_disable(struct pwm_chip * chip,struct pwm_device * pwm)149 static void atmel_tcb_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
150 {
151 struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
152 struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);
153 unsigned cmr;
154 enum pwm_polarity polarity = tcbpwm->polarity;
155
156 /*
157 * If duty is 0 the timer will be stopped and we have to
158 * configure the output correctly on software trigger:
159 * - set output to high if PWM_POLARITY_INVERSED
160 * - set output to low if PWM_POLARITY_NORMAL
161 *
162 * This is why we're reverting polarity in this case.
163 */
164 if (tcbpwm->duty == 0)
165 polarity = !polarity;
166
167 spin_lock(&tcbpwmc->lock);
168 regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), &cmr);
169
170 /* flush old setting and set the new one */
171 if (pwm->hwpwm == 0) {
172 cmr &= ~ATMEL_TC_ACMR_MASK;
173 if (polarity == PWM_POLARITY_INVERSED)
174 cmr |= ATMEL_TC_ASWTRG_CLEAR;
175 else
176 cmr |= ATMEL_TC_ASWTRG_SET;
177 } else {
178 cmr &= ~ATMEL_TC_BCMR_MASK;
179 if (polarity == PWM_POLARITY_INVERSED)
180 cmr |= ATMEL_TC_BSWTRG_CLEAR;
181 else
182 cmr |= ATMEL_TC_BSWTRG_SET;
183 }
184
185 regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), cmr);
186
187 /*
188 * Use software trigger to apply the new setting.
189 * If both PWM devices in this group are disabled we stop the clock.
190 */
191 if (!(cmr & (ATMEL_TC_ACPC | ATMEL_TC_BCPC))) {
192 regmap_write(tcbpwmc->regmap,
193 ATMEL_TC_REG(tcbpwmc->channel, CCR),
194 ATMEL_TC_SWTRG | ATMEL_TC_CLKDIS);
195 tcbpwmc->bkup.enabled = 1;
196 } else {
197 regmap_write(tcbpwmc->regmap,
198 ATMEL_TC_REG(tcbpwmc->channel, CCR),
199 ATMEL_TC_SWTRG);
200 tcbpwmc->bkup.enabled = 0;
201 }
202
203 spin_unlock(&tcbpwmc->lock);
204 }
205
atmel_tcb_pwm_enable(struct pwm_chip * chip,struct pwm_device * pwm)206 static int atmel_tcb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
207 {
208 struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
209 struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);
210 u32 cmr;
211 enum pwm_polarity polarity = tcbpwm->polarity;
212
213 /*
214 * If duty is 0 the timer will be stopped and we have to
215 * configure the output correctly on software trigger:
216 * - set output to high if PWM_POLARITY_INVERSED
217 * - set output to low if PWM_POLARITY_NORMAL
218 *
219 * This is why we're reverting polarity in this case.
220 */
221 if (tcbpwm->duty == 0)
222 polarity = !polarity;
223
224 spin_lock(&tcbpwmc->lock);
225 regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), &cmr);
226
227 /* flush old setting and set the new one */
228 cmr &= ~ATMEL_TC_TCCLKS;
229
230 if (pwm->hwpwm == 0) {
231 cmr &= ~ATMEL_TC_ACMR_MASK;
232
233 /* Set CMR flags according to given polarity */
234 if (polarity == PWM_POLARITY_INVERSED)
235 cmr |= ATMEL_TC_ASWTRG_CLEAR;
236 else
237 cmr |= ATMEL_TC_ASWTRG_SET;
238 } else {
239 cmr &= ~ATMEL_TC_BCMR_MASK;
240 if (polarity == PWM_POLARITY_INVERSED)
241 cmr |= ATMEL_TC_BSWTRG_CLEAR;
242 else
243 cmr |= ATMEL_TC_BSWTRG_SET;
244 }
245
246 /*
247 * If duty is 0 or equal to period there's no need to register
248 * a specific action on RA/RB and RC compare.
249 * The output will be configured on software trigger and keep
250 * this config till next config call.
251 */
252 if (tcbpwm->duty != tcbpwm->period && tcbpwm->duty > 0) {
253 if (pwm->hwpwm == 0) {
254 if (polarity == PWM_POLARITY_INVERSED)
255 cmr |= ATMEL_TC_ACPA_SET | ATMEL_TC_ACPC_CLEAR;
256 else
257 cmr |= ATMEL_TC_ACPA_CLEAR | ATMEL_TC_ACPC_SET;
258 } else {
259 if (polarity == PWM_POLARITY_INVERSED)
260 cmr |= ATMEL_TC_BCPB_SET | ATMEL_TC_BCPC_CLEAR;
261 else
262 cmr |= ATMEL_TC_BCPB_CLEAR | ATMEL_TC_BCPC_SET;
263 }
264 }
265
266 cmr |= (tcbpwm->div & ATMEL_TC_TCCLKS);
267
268 regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), cmr);
269
270 if (pwm->hwpwm == 0)
271 regmap_write(tcbpwmc->regmap,
272 ATMEL_TC_REG(tcbpwmc->channel, RA),
273 tcbpwm->duty);
274 else
275 regmap_write(tcbpwmc->regmap,
276 ATMEL_TC_REG(tcbpwmc->channel, RB),
277 tcbpwm->duty);
278
279 regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, RC),
280 tcbpwm->period);
281
282 /* Use software trigger to apply the new setting */
283 regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CCR),
284 ATMEL_TC_SWTRG | ATMEL_TC_CLKEN);
285 tcbpwmc->bkup.enabled = 1;
286 spin_unlock(&tcbpwmc->lock);
287 return 0;
288 }
289
atmel_tcb_pwm_config(struct pwm_chip * chip,struct pwm_device * pwm,int duty_ns,int period_ns)290 static int atmel_tcb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
291 int duty_ns, int period_ns)
292 {
293 struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
294 struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);
295 struct atmel_tcb_pwm_device *atcbpwm = NULL;
296 int i = 0;
297 int slowclk = 0;
298 unsigned period;
299 unsigned duty;
300 unsigned rate = clk_get_rate(tcbpwmc->clk);
301 unsigned long long min;
302 unsigned long long max;
303
304 /*
305 * Find best clk divisor:
306 * the smallest divisor which can fulfill the period_ns requirements.
307 * If there is a gclk, the first divisor is actuallly the gclk selector
308 */
309 if (tcbpwmc->gclk)
310 i = 1;
311 for (; i < ARRAY_SIZE(atmel_tcb_divisors); ++i) {
312 if (atmel_tcb_divisors[i] == 0) {
313 slowclk = i;
314 continue;
315 }
316 min = div_u64((u64)NSEC_PER_SEC * atmel_tcb_divisors[i], rate);
317 max = min << tcbpwmc->width;
318 if (max >= period_ns)
319 break;
320 }
321
322 /*
323 * If none of the divisor are small enough to represent period_ns
324 * take slow clock (32KHz).
325 */
326 if (i == ARRAY_SIZE(atmel_tcb_divisors)) {
327 i = slowclk;
328 rate = clk_get_rate(tcbpwmc->slow_clk);
329 min = div_u64(NSEC_PER_SEC, rate);
330 max = min << tcbpwmc->width;
331
332 /* If period is too big return ERANGE error */
333 if (max < period_ns)
334 return -ERANGE;
335 }
336
337 duty = div_u64(duty_ns, min);
338 period = div_u64(period_ns, min);
339
340 if (pwm->hwpwm == 0)
341 atcbpwm = tcbpwmc->pwms[1];
342 else
343 atcbpwm = tcbpwmc->pwms[0];
344
345 /*
346 * PWM devices provided by the TCB driver are grouped by 2.
347 * PWM devices in a given group must be configured with the
348 * same period_ns.
349 *
350 * We're checking the period value of the second PWM device
351 * in this group before applying the new config.
352 */
353 if ((atcbpwm && atcbpwm->duty > 0 &&
354 atcbpwm->duty != atcbpwm->period) &&
355 (atcbpwm->div != i || atcbpwm->period != period)) {
356 dev_err(chip->dev,
357 "failed to configure period_ns: PWM group already configured with a different value\n");
358 return -EINVAL;
359 }
360
361 tcbpwm->period = period;
362 tcbpwm->div = i;
363 tcbpwm->duty = duty;
364
365 return 0;
366 }
367
atmel_tcb_pwm_apply(struct pwm_chip * chip,struct pwm_device * pwm,const struct pwm_state * state)368 static int atmel_tcb_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
369 const struct pwm_state *state)
370 {
371 int duty_cycle, period;
372 int ret;
373
374 /* This function only sets a flag in driver data */
375 atmel_tcb_pwm_set_polarity(chip, pwm, state->polarity);
376
377 if (!state->enabled) {
378 atmel_tcb_pwm_disable(chip, pwm);
379 return 0;
380 }
381
382 period = state->period < INT_MAX ? state->period : INT_MAX;
383 duty_cycle = state->duty_cycle < INT_MAX ? state->duty_cycle : INT_MAX;
384
385 ret = atmel_tcb_pwm_config(chip, pwm, duty_cycle, period);
386 if (ret)
387 return ret;
388
389 return atmel_tcb_pwm_enable(chip, pwm);
390 }
391
392 static const struct pwm_ops atmel_tcb_pwm_ops = {
393 .request = atmel_tcb_pwm_request,
394 .free = atmel_tcb_pwm_free,
395 .apply = atmel_tcb_pwm_apply,
396 .owner = THIS_MODULE,
397 };
398
399 static struct atmel_tcb_config tcb_rm9200_config = {
400 .counter_width = 16,
401 };
402
403 static struct atmel_tcb_config tcb_sam9x5_config = {
404 .counter_width = 32,
405 };
406
407 static struct atmel_tcb_config tcb_sama5d2_config = {
408 .counter_width = 32,
409 .has_gclk = 1,
410 };
411
412 static const struct of_device_id atmel_tcb_of_match[] = {
413 { .compatible = "atmel,at91rm9200-tcb", .data = &tcb_rm9200_config, },
414 { .compatible = "atmel,at91sam9x5-tcb", .data = &tcb_sam9x5_config, },
415 { .compatible = "atmel,sama5d2-tcb", .data = &tcb_sama5d2_config, },
416 { /* sentinel */ }
417 };
418
atmel_tcb_pwm_probe(struct platform_device * pdev)419 static int atmel_tcb_pwm_probe(struct platform_device *pdev)
420 {
421 const struct of_device_id *match;
422 struct atmel_tcb_pwm_chip *tcbpwm;
423 const struct atmel_tcb_config *config;
424 struct device_node *np = pdev->dev.of_node;
425 struct regmap *regmap;
426 struct clk *clk, *gclk = NULL;
427 struct clk *slow_clk;
428 char clk_name[] = "t0_clk";
429 int err;
430 int channel;
431
432 err = of_property_read_u32(np, "reg", &channel);
433 if (err < 0) {
434 dev_err(&pdev->dev,
435 "failed to get Timer Counter Block channel from device tree (error: %d)\n",
436 err);
437 return err;
438 }
439
440 regmap = syscon_node_to_regmap(np->parent);
441 if (IS_ERR(regmap))
442 return PTR_ERR(regmap);
443
444 slow_clk = of_clk_get_by_name(np->parent, "slow_clk");
445 if (IS_ERR(slow_clk))
446 return PTR_ERR(slow_clk);
447
448 clk_name[1] += channel;
449 clk = of_clk_get_by_name(np->parent, clk_name);
450 if (IS_ERR(clk))
451 clk = of_clk_get_by_name(np->parent, "t0_clk");
452 if (IS_ERR(clk))
453 return PTR_ERR(clk);
454
455 match = of_match_node(atmel_tcb_of_match, np->parent);
456 config = match->data;
457
458 if (config->has_gclk) {
459 gclk = of_clk_get_by_name(np->parent, "gclk");
460 if (IS_ERR(gclk))
461 return PTR_ERR(gclk);
462 }
463
464 tcbpwm = devm_kzalloc(&pdev->dev, sizeof(*tcbpwm), GFP_KERNEL);
465 if (tcbpwm == NULL) {
466 err = -ENOMEM;
467 goto err_slow_clk;
468 }
469
470 tcbpwm->chip.dev = &pdev->dev;
471 tcbpwm->chip.ops = &atmel_tcb_pwm_ops;
472 tcbpwm->chip.of_xlate = of_pwm_xlate_with_flags;
473 tcbpwm->chip.of_pwm_n_cells = 3;
474 tcbpwm->chip.npwm = NPWM;
475 tcbpwm->channel = channel;
476 tcbpwm->regmap = regmap;
477 tcbpwm->clk = clk;
478 tcbpwm->gclk = gclk;
479 tcbpwm->slow_clk = slow_clk;
480 tcbpwm->width = config->counter_width;
481
482 err = clk_prepare_enable(slow_clk);
483 if (err)
484 goto err_slow_clk;
485
486 spin_lock_init(&tcbpwm->lock);
487
488 err = pwmchip_add(&tcbpwm->chip);
489 if (err < 0)
490 goto err_disable_clk;
491
492 platform_set_drvdata(pdev, tcbpwm);
493
494 return 0;
495
496 err_disable_clk:
497 clk_disable_unprepare(tcbpwm->slow_clk);
498
499 err_slow_clk:
500 clk_put(slow_clk);
501
502 return err;
503 }
504
atmel_tcb_pwm_remove(struct platform_device * pdev)505 static int atmel_tcb_pwm_remove(struct platform_device *pdev)
506 {
507 struct atmel_tcb_pwm_chip *tcbpwm = platform_get_drvdata(pdev);
508 int err;
509
510 err = pwmchip_remove(&tcbpwm->chip);
511 if (err < 0)
512 return err;
513
514 clk_disable_unprepare(tcbpwm->slow_clk);
515 clk_put(tcbpwm->slow_clk);
516 clk_put(tcbpwm->clk);
517
518 return 0;
519 }
520
521 static const struct of_device_id atmel_tcb_pwm_dt_ids[] = {
522 { .compatible = "atmel,tcb-pwm", },
523 { /* sentinel */ }
524 };
525 MODULE_DEVICE_TABLE(of, atmel_tcb_pwm_dt_ids);
526
527 #ifdef CONFIG_PM_SLEEP
atmel_tcb_pwm_suspend(struct device * dev)528 static int atmel_tcb_pwm_suspend(struct device *dev)
529 {
530 struct atmel_tcb_pwm_chip *tcbpwm = dev_get_drvdata(dev);
531 struct atmel_tcb_channel *chan = &tcbpwm->bkup;
532 unsigned int channel = tcbpwm->channel;
533
534 regmap_read(tcbpwm->regmap, ATMEL_TC_REG(channel, CMR), &chan->cmr);
535 regmap_read(tcbpwm->regmap, ATMEL_TC_REG(channel, RA), &chan->ra);
536 regmap_read(tcbpwm->regmap, ATMEL_TC_REG(channel, RB), &chan->rb);
537 regmap_read(tcbpwm->regmap, ATMEL_TC_REG(channel, RC), &chan->rc);
538
539 return 0;
540 }
541
atmel_tcb_pwm_resume(struct device * dev)542 static int atmel_tcb_pwm_resume(struct device *dev)
543 {
544 struct atmel_tcb_pwm_chip *tcbpwm = dev_get_drvdata(dev);
545 struct atmel_tcb_channel *chan = &tcbpwm->bkup;
546 unsigned int channel = tcbpwm->channel;
547
548 regmap_write(tcbpwm->regmap, ATMEL_TC_REG(channel, CMR), chan->cmr);
549 regmap_write(tcbpwm->regmap, ATMEL_TC_REG(channel, RA), chan->ra);
550 regmap_write(tcbpwm->regmap, ATMEL_TC_REG(channel, RB), chan->rb);
551 regmap_write(tcbpwm->regmap, ATMEL_TC_REG(channel, RC), chan->rc);
552
553 if (chan->enabled)
554 regmap_write(tcbpwm->regmap,
555 ATMEL_TC_CLKEN | ATMEL_TC_SWTRG,
556 ATMEL_TC_REG(channel, CCR));
557
558 return 0;
559 }
560 #endif
561
562 static SIMPLE_DEV_PM_OPS(atmel_tcb_pwm_pm_ops, atmel_tcb_pwm_suspend,
563 atmel_tcb_pwm_resume);
564
565 static struct platform_driver atmel_tcb_pwm_driver = {
566 .driver = {
567 .name = "atmel-tcb-pwm",
568 .of_match_table = atmel_tcb_pwm_dt_ids,
569 .pm = &atmel_tcb_pwm_pm_ops,
570 },
571 .probe = atmel_tcb_pwm_probe,
572 .remove = atmel_tcb_pwm_remove,
573 };
574 module_platform_driver(atmel_tcb_pwm_driver);
575
576 MODULE_AUTHOR("Boris BREZILLON <b.brezillon@overkiz.com>");
577 MODULE_DESCRIPTION("Atmel Timer Counter Pulse Width Modulation Driver");
578 MODULE_LICENSE("GPL v2");
579