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1/*
2 * Copyright (c) 2007 Ben Dooks
3 * Copyright (c) 2008 Simtec Electronics
4 * Ben Dooks <ben@simtec.co.uk>, <ben-linux@fluff.org>
5 * Copyright (c) 2013 Tomasz Figa <tomasz.figa@gmail.com>
6 * Copyright (c) 2017 Samsung Electronics Co., Ltd.
7 *
8 * PWM driver for Samsung SoCs
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License.
13 */
14
15#include <linux/bitops.h>
16#include <linux/clk.h>
17#include <linux/export.h>
18#include <linux/err.h>
19#include <linux/io.h>
20#include <linux/kernel.h>
21#include <linux/module.h>
22#include <linux/of.h>
23#include <linux/platform_device.h>
24#include <linux/pwm.h>
25#include <linux/slab.h>
26#include <linux/spinlock.h>
27#include <linux/time.h>
28
29/* For struct samsung_timer_variant and samsung_pwm_lock. */
30#include <clocksource/samsung_pwm.h>
31
32#define REG_TCFG0 0x00
33#define REG_TCFG1 0x04
34#define REG_TCON 0x08
35
36#define REG_TCNTB(chan) (0x0c + ((chan) * 0xc))
37#define REG_TCMPB(chan) (0x10 + ((chan) * 0xc))
38
39#define TCFG0_PRESCALER_MASK 0xff
40#define TCFG0_PRESCALER1_SHIFT 8
41
42#define TCFG1_MUX_MASK 0xf
43#define TCFG1_SHIFT(chan) (4 * (chan))
44
45/*
46 * Each channel occupies 4 bits in TCON register, but there is a gap of 4
47 * bits (one channel) after channel 0, so channels have different numbering
48 * when accessing TCON register. See to_tcon_channel() function.
49 *
50 * In addition, the location of autoreload bit for channel 4 (TCON channel 5)
51 * in its set of bits is 2 as opposed to 3 for other channels.
52 */
53#define TCON_START(chan) BIT(4 * (chan) + 0)
54#define TCON_MANUALUPDATE(chan) BIT(4 * (chan) + 1)
55#define TCON_INVERT(chan) BIT(4 * (chan) + 2)
56#define _TCON_AUTORELOAD(chan) BIT(4 * (chan) + 3)
57#define _TCON_AUTORELOAD4(chan) BIT(4 * (chan) + 2)
58#define TCON_AUTORELOAD(chan) \
59 ((chan < 5) ? _TCON_AUTORELOAD(chan) : _TCON_AUTORELOAD4(chan))
60
61/**
62 * struct samsung_pwm_channel - private data of PWM channel
63 * @period_ns: current period in nanoseconds programmed to the hardware
64 * @duty_ns: current duty time in nanoseconds programmed to the hardware
65 * @tin_ns: time of one timer tick in nanoseconds with current timer rate
66 */
67struct samsung_pwm_channel {
68 u32 period_ns;
69 u32 duty_ns;
70 u32 tin_ns;
71};
72
73/**
74 * struct samsung_pwm_chip - private data of PWM chip
75 * @chip: generic PWM chip
76 * @variant: local copy of hardware variant data
77 * @inverter_mask: inverter status for all channels - one bit per channel
78 * @disabled_mask: disabled status for all channels - one bit per channel
79 * @base: base address of mapped PWM registers
80 * @base_clk: base clock used to drive the timers
81 * @tclk0: external clock 0 (can be ERR_PTR if not present)
82 * @tclk1: external clock 1 (can be ERR_PTR if not present)
83 */
84struct samsung_pwm_chip {
85 struct pwm_chip chip;
86 struct samsung_pwm_variant variant;
87 u8 inverter_mask;
88 u8 disabled_mask;
89
90 void __iomem *base;
91 struct clk *base_clk;
92 struct clk *tclk0;
93 struct clk *tclk1;
94};
95
96#ifndef CONFIG_CLKSRC_SAMSUNG_PWM
97/*
98 * PWM block is shared between pwm-samsung and samsung_pwm_timer drivers
99 * and some registers need access synchronization. If both drivers are
100 * compiled in, the spinlock is defined in the clocksource driver,
101 * otherwise following definition is used.
102 *
103 * Currently we do not need any more complex synchronization method
104 * because all the supported SoCs contain only one instance of the PWM
105 * IP. Should this change, both drivers will need to be modified to
106 * properly synchronize accesses to particular instances.
107 */
108static DEFINE_SPINLOCK(samsung_pwm_lock);
109#endif
110
111static inline
112struct samsung_pwm_chip *to_samsung_pwm_chip(struct pwm_chip *chip)
113{
114 return container_of(chip, struct samsung_pwm_chip, chip);
115}
116
117static inline unsigned int to_tcon_channel(unsigned int channel)
118{
119 /* TCON register has a gap of 4 bits (1 channel) after channel 0 */
120 return (channel == 0) ? 0 : (channel + 1);
121}
122
123static void pwm_samsung_set_divisor(struct samsung_pwm_chip *pwm,
124 unsigned int channel, u8 divisor)
125{
126 u8 shift = TCFG1_SHIFT(channel);
127 unsigned long flags;
128 u32 reg;
129 u8 bits;
130
131 bits = (fls(divisor) - 1) - pwm->variant.div_base;
132
133 spin_lock_irqsave(&samsung_pwm_lock, flags);
134
135 reg = readl(pwm->base + REG_TCFG1);
136 reg &= ~(TCFG1_MUX_MASK << shift);
137 reg |= bits << shift;
138 writel(reg, pwm->base + REG_TCFG1);
139
140 spin_unlock_irqrestore(&samsung_pwm_lock, flags);
141}
142
143static int pwm_samsung_is_tdiv(struct samsung_pwm_chip *chip, unsigned int chan)
144{
145 struct samsung_pwm_variant *variant = &chip->variant;
146 u32 reg;
147
148 reg = readl(chip->base + REG_TCFG1);
149 reg >>= TCFG1_SHIFT(chan);
150 reg &= TCFG1_MUX_MASK;
151
152 return (BIT(reg) & variant->tclk_mask) == 0;
153}
154
155static unsigned long pwm_samsung_get_tin_rate(struct samsung_pwm_chip *chip,
156 unsigned int chan)
157{
158 unsigned long rate;
159 u32 reg;
160
161 rate = clk_get_rate(chip->base_clk);
162
163 reg = readl(chip->base + REG_TCFG0);
164 if (chan >= 2)
165 reg >>= TCFG0_PRESCALER1_SHIFT;
166 reg &= TCFG0_PRESCALER_MASK;
167
168 return rate / (reg + 1);
169}
170
171static unsigned long pwm_samsung_calc_tin(struct samsung_pwm_chip *chip,
172 unsigned int chan, unsigned long freq)
173{
174 struct samsung_pwm_variant *variant = &chip->variant;
175 unsigned long rate;
176 struct clk *clk;
177 u8 div;
178
179 if (!pwm_samsung_is_tdiv(chip, chan)) {
180 clk = (chan < 2) ? chip->tclk0 : chip->tclk1;
181 if (!IS_ERR(clk)) {
182 rate = clk_get_rate(clk);
183 if (rate)
184 return rate;
185 }
186
187 dev_warn(chip->chip.dev,
188 "tclk of PWM %d is inoperational, using tdiv\n", chan);
189 }
190
191 rate = pwm_samsung_get_tin_rate(chip, chan);
192 dev_dbg(chip->chip.dev, "tin parent at %lu\n", rate);
193
194 /*
195 * Compare minimum PWM frequency that can be achieved with possible
196 * divider settings and choose the lowest divisor that can generate
197 * frequencies lower than requested.
198 */
199 if (variant->bits < 32) {
200 /* Only for s3c24xx */
201 for (div = variant->div_base; div < 4; ++div)
202 if ((rate >> (variant->bits + div)) < freq)
203 break;
204 } else {
205 /*
206 * Other variants have enough counter bits to generate any
207 * requested rate, so no need to check higher divisors.
208 */
209 div = variant->div_base;
210 }
211
212 pwm_samsung_set_divisor(chip, chan, BIT(div));
213
214 return rate >> div;
215}
216
217static int pwm_samsung_request(struct pwm_chip *chip, struct pwm_device *pwm)
218{
219 struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
220 struct samsung_pwm_channel *our_chan;
221
222 if (!(our_chip->variant.output_mask & BIT(pwm->hwpwm))) {
223 dev_warn(chip->dev,
224 "tried to request PWM channel %d without output\n",
225 pwm->hwpwm);
226 return -EINVAL;
227 }
228
229 our_chan = devm_kzalloc(chip->dev, sizeof(*our_chan), GFP_KERNEL);
230 if (!our_chan)
231 return -ENOMEM;
232
233 pwm_set_chip_data(pwm, our_chan);
234
235 return 0;
236}
237
238static void pwm_samsung_free(struct pwm_chip *chip, struct pwm_device *pwm)
239{
240 devm_kfree(chip->dev, pwm_get_chip_data(pwm));
241 pwm_set_chip_data(pwm, NULL);
242}
243
244static int pwm_samsung_enable(struct pwm_chip *chip, struct pwm_device *pwm)
245{
246 struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
247 unsigned int tcon_chan = to_tcon_channel(pwm->hwpwm);
248 unsigned long flags;
249 u32 tcon;
250
251 spin_lock_irqsave(&samsung_pwm_lock, flags);
252
253 tcon = readl(our_chip->base + REG_TCON);
254
255 tcon &= ~TCON_START(tcon_chan);
256 tcon |= TCON_MANUALUPDATE(tcon_chan);
257 writel(tcon, our_chip->base + REG_TCON);
258
259 tcon &= ~TCON_MANUALUPDATE(tcon_chan);
260 tcon |= TCON_START(tcon_chan) | TCON_AUTORELOAD(tcon_chan);
261 writel(tcon, our_chip->base + REG_TCON);
262
263 our_chip->disabled_mask &= ~BIT(pwm->hwpwm);
264
265 spin_unlock_irqrestore(&samsung_pwm_lock, flags);
266
267 return 0;
268}
269
270static void pwm_samsung_disable(struct pwm_chip *chip, struct pwm_device *pwm)
271{
272 struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
273 unsigned int tcon_chan = to_tcon_channel(pwm->hwpwm);
274 unsigned long flags;
275 u32 tcon;
276
277 spin_lock_irqsave(&samsung_pwm_lock, flags);
278
279 tcon = readl(our_chip->base + REG_TCON);
280 tcon &= ~TCON_AUTORELOAD(tcon_chan);
281 writel(tcon, our_chip->base + REG_TCON);
282
283 our_chip->disabled_mask |= BIT(pwm->hwpwm);
284
285 spin_unlock_irqrestore(&samsung_pwm_lock, flags);
286}
287
288static void pwm_samsung_manual_update(struct samsung_pwm_chip *chip,
289 struct pwm_device *pwm)
290{
291 unsigned int tcon_chan = to_tcon_channel(pwm->hwpwm);
292 u32 tcon;
293 unsigned long flags;
294
295 spin_lock_irqsave(&samsung_pwm_lock, flags);
296
297 tcon = readl(chip->base + REG_TCON);
298 tcon |= TCON_MANUALUPDATE(tcon_chan);
299 writel(tcon, chip->base + REG_TCON);
300
301 tcon &= ~TCON_MANUALUPDATE(tcon_chan);
302 writel(tcon, chip->base + REG_TCON);
303
304 spin_unlock_irqrestore(&samsung_pwm_lock, flags);
305}
306
307static int __pwm_samsung_config(struct pwm_chip *chip, struct pwm_device *pwm,
308 int duty_ns, int period_ns, bool force_period)
309{
310 struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
311 struct samsung_pwm_channel *chan = pwm_get_chip_data(pwm);
312 u32 tin_ns = chan->tin_ns, tcnt, tcmp, oldtcmp;
313
314 /*
315 * We currently avoid using 64bit arithmetic by using the
316 * fact that anything faster than 1Hz is easily representable
317 * by 32bits.
318 */
319 if (period_ns > NSEC_PER_SEC)
320 return -ERANGE;
321
322 tcnt = readl(our_chip->base + REG_TCNTB(pwm->hwpwm));
323 oldtcmp = readl(our_chip->base + REG_TCMPB(pwm->hwpwm));
324
325 /* We need tick count for calculation, not last tick. */
326 ++tcnt;
327
328 /* Check to see if we are changing the clock rate of the PWM. */
329 if (chan->period_ns != period_ns || force_period) {
330 unsigned long tin_rate;
331 u32 period;
332
333 period = NSEC_PER_SEC / period_ns;
334
335 dev_dbg(our_chip->chip.dev, "duty_ns=%d, period_ns=%d (%u)\n",
336 duty_ns, period_ns, period);
337
338 tin_rate = pwm_samsung_calc_tin(our_chip, pwm->hwpwm, period);
339
340 dev_dbg(our_chip->chip.dev, "tin_rate=%lu\n", tin_rate);
341
342 tin_ns = NSEC_PER_SEC / tin_rate;
343 tcnt = period_ns / tin_ns;
344 }
345
346 /* Period is too short. */
347 if (tcnt <= 1)
348 return -ERANGE;
349
350 /* Note that counters count down. */
351 tcmp = duty_ns / tin_ns;
352
353 /* 0% duty is not available */
354 if (!tcmp)
355 ++tcmp;
356
357 tcmp = tcnt - tcmp;
358
359 /* Decrement to get tick numbers, instead of tick counts. */
360 --tcnt;
361 /* -1UL will give 100% duty. */
362 --tcmp;
363
364 dev_dbg(our_chip->chip.dev,
365 "tin_ns=%u, tcmp=%u/%u\n", tin_ns, tcmp, tcnt);
366
367 /* Update PWM registers. */
368 writel(tcnt, our_chip->base + REG_TCNTB(pwm->hwpwm));
369 writel(tcmp, our_chip->base + REG_TCMPB(pwm->hwpwm));
370
371 /*
372 * In case the PWM is currently at 100% duty cycle, force a manual
373 * update to prevent the signal staying high if the PWM is disabled
374 * shortly afer this update (before it autoreloaded the new values).
375 */
376 if (oldtcmp == (u32) -1) {
377 dev_dbg(our_chip->chip.dev, "Forcing manual update");
378 pwm_samsung_manual_update(our_chip, pwm);
379 }
380
381 chan->period_ns = period_ns;
382 chan->tin_ns = tin_ns;
383 chan->duty_ns = duty_ns;
384
385 return 0;
386}
387
388static int pwm_samsung_config(struct pwm_chip *chip, struct pwm_device *pwm,
389 int duty_ns, int period_ns)
390{
391 return __pwm_samsung_config(chip, pwm, duty_ns, period_ns, false);
392}
393
394static void pwm_samsung_set_invert(struct samsung_pwm_chip *chip,
395 unsigned int channel, bool invert)
396{
397 unsigned int tcon_chan = to_tcon_channel(channel);
398 unsigned long flags;
399 u32 tcon;
400
401 spin_lock_irqsave(&samsung_pwm_lock, flags);
402
403 tcon = readl(chip->base + REG_TCON);
404
405 if (invert) {
406 chip->inverter_mask |= BIT(channel);
407 tcon |= TCON_INVERT(tcon_chan);
408 } else {
409 chip->inverter_mask &= ~BIT(channel);
410 tcon &= ~TCON_INVERT(tcon_chan);
411 }
412
413 writel(tcon, chip->base + REG_TCON);
414
415 spin_unlock_irqrestore(&samsung_pwm_lock, flags);
416}
417
418static int pwm_samsung_set_polarity(struct pwm_chip *chip,
419 struct pwm_device *pwm,
420 enum pwm_polarity polarity)
421{
422 struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
423 bool invert = (polarity == PWM_POLARITY_NORMAL);
424
425 /* Inverted means normal in the hardware. */
426 pwm_samsung_set_invert(our_chip, pwm->hwpwm, invert);
427
428 return 0;
429}
430
431static const struct pwm_ops pwm_samsung_ops = {
432 .request = pwm_samsung_request,
433 .free = pwm_samsung_free,
434 .enable = pwm_samsung_enable,
435 .disable = pwm_samsung_disable,
436 .config = pwm_samsung_config,
437 .set_polarity = pwm_samsung_set_polarity,
438 .owner = THIS_MODULE,
439};
440
441#ifdef CONFIG_OF
442static const struct samsung_pwm_variant s3c24xx_variant = {
443 .bits = 16,
444 .div_base = 1,
445 .has_tint_cstat = false,
446 .tclk_mask = BIT(4),
447};
448
449static const struct samsung_pwm_variant s3c64xx_variant = {
450 .bits = 32,
451 .div_base = 0,
452 .has_tint_cstat = true,
453 .tclk_mask = BIT(7) | BIT(6) | BIT(5),
454};
455
456static const struct samsung_pwm_variant s5p64x0_variant = {
457 .bits = 32,
458 .div_base = 0,
459 .has_tint_cstat = true,
460 .tclk_mask = 0,
461};
462
463static const struct samsung_pwm_variant s5pc100_variant = {
464 .bits = 32,
465 .div_base = 0,
466 .has_tint_cstat = true,
467 .tclk_mask = BIT(5),
468};
469
470static const struct of_device_id samsung_pwm_matches[] = {
471 { .compatible = "samsung,s3c2410-pwm", .data = &s3c24xx_variant },
472 { .compatible = "samsung,s3c6400-pwm", .data = &s3c64xx_variant },
473 { .compatible = "samsung,s5p6440-pwm", .data = &s5p64x0_variant },
474 { .compatible = "samsung,s5pc100-pwm", .data = &s5pc100_variant },
475 { .compatible = "samsung,exynos4210-pwm", .data = &s5p64x0_variant },
476 {},
477};
478MODULE_DEVICE_TABLE(of, samsung_pwm_matches);
479
480static int pwm_samsung_parse_dt(struct samsung_pwm_chip *chip)
481{
482 struct device_node *np = chip->chip.dev->of_node;
483 const struct of_device_id *match;
484 struct property *prop;
485 const __be32 *cur;
486 u32 val;
487
488 match = of_match_node(samsung_pwm_matches, np);
489 if (!match)
490 return -ENODEV;
491
492 memcpy(&chip->variant, match->data, sizeof(chip->variant));
493
494 of_property_for_each_u32(np, "samsung,pwm-outputs", prop, cur, val) {
495 if (val >= SAMSUNG_PWM_NUM) {
496 dev_err(chip->chip.dev,
497 "%s: invalid channel index in samsung,pwm-outputs property\n",
498 __func__);
499 continue;
500 }
501 chip->variant.output_mask |= BIT(val);
502 }
503
504 return 0;
505}
506#else
507static int pwm_samsung_parse_dt(struct samsung_pwm_chip *chip)
508{
509 return -ENODEV;
510}
511#endif
512
513static int pwm_samsung_probe(struct platform_device *pdev)
514{
515 struct device *dev = &pdev->dev;
516 struct samsung_pwm_chip *chip;
517 struct resource *res;
518 unsigned int chan;
519 int ret;
520
521 chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
522 if (chip == NULL)
523 return -ENOMEM;
524
525 chip->chip.dev = &pdev->dev;
526 chip->chip.ops = &pwm_samsung_ops;
527 chip->chip.base = -1;
528 chip->chip.npwm = SAMSUNG_PWM_NUM;
529 chip->inverter_mask = BIT(SAMSUNG_PWM_NUM) - 1;
530
531 if (IS_ENABLED(CONFIG_OF) && pdev->dev.of_node) {
532 ret = pwm_samsung_parse_dt(chip);
533 if (ret)
534 return ret;
535
536 chip->chip.of_xlate = of_pwm_xlate_with_flags;
537 chip->chip.of_pwm_n_cells = 3;
538 } else {
539 if (!pdev->dev.platform_data) {
540 dev_err(&pdev->dev, "no platform data specified\n");
541 return -EINVAL;
542 }
543
544 memcpy(&chip->variant, pdev->dev.platform_data,
545 sizeof(chip->variant));
546 }
547
548 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
549 chip->base = devm_ioremap_resource(&pdev->dev, res);
550 if (IS_ERR(chip->base))
551 return PTR_ERR(chip->base);
552
553 chip->base_clk = devm_clk_get(&pdev->dev, "timers");
554 if (IS_ERR(chip->base_clk)) {
555 dev_err(dev, "failed to get timer base clk\n");
556 return PTR_ERR(chip->base_clk);
557 }
558
559 ret = clk_prepare_enable(chip->base_clk);
560 if (ret < 0) {
561 dev_err(dev, "failed to enable base clock\n");
562 return ret;
563 }
564
565 for (chan = 0; chan < SAMSUNG_PWM_NUM; ++chan)
566 if (chip->variant.output_mask & BIT(chan))
567 pwm_samsung_set_invert(chip, chan, true);
568
569 /* Following clocks are optional. */
570 chip->tclk0 = devm_clk_get(&pdev->dev, "pwm-tclk0");
571 chip->tclk1 = devm_clk_get(&pdev->dev, "pwm-tclk1");
572
573 platform_set_drvdata(pdev, chip);
574
575 ret = pwmchip_add(&chip->chip);
576 if (ret < 0) {
577 dev_err(dev, "failed to register PWM chip\n");
578 clk_disable_unprepare(chip->base_clk);
579 return ret;
580 }
581
582 dev_dbg(dev, "base_clk at %lu, tclk0 at %lu, tclk1 at %lu\n",
583 clk_get_rate(chip->base_clk),
584 !IS_ERR(chip->tclk0) ? clk_get_rate(chip->tclk0) : 0,
585 !IS_ERR(chip->tclk1) ? clk_get_rate(chip->tclk1) : 0);
586
587 return 0;
588}
589
590static int pwm_samsung_remove(struct platform_device *pdev)
591{
592 struct samsung_pwm_chip *chip = platform_get_drvdata(pdev);
593 int ret;
594
595 ret = pwmchip_remove(&chip->chip);
596 if (ret < 0)
597 return ret;
598
599 clk_disable_unprepare(chip->base_clk);
600
601 return 0;
602}
603
604#ifdef CONFIG_PM_SLEEP
605static int pwm_samsung_resume(struct device *dev)
606{
607 struct samsung_pwm_chip *our_chip = dev_get_drvdata(dev);
608 struct pwm_chip *chip = &our_chip->chip;
609 unsigned int i;
610
611 for (i = 0; i < SAMSUNG_PWM_NUM; i++) {
612 struct pwm_device *pwm = &chip->pwms[i];
613 struct samsung_pwm_channel *chan = pwm_get_chip_data(pwm);
614
615 if (!chan)
616 continue;
617
618 if (our_chip->variant.output_mask & BIT(i))
619 pwm_samsung_set_invert(our_chip, i,
620 our_chip->inverter_mask & BIT(i));
621
622 if (chan->period_ns) {
623 __pwm_samsung_config(chip, pwm, chan->duty_ns,
624 chan->period_ns, true);
625 /* needed to make PWM disable work on Odroid-XU3 */
626 pwm_samsung_manual_update(our_chip, pwm);
627 }
628
629 if (our_chip->disabled_mask & BIT(i))
630 pwm_samsung_disable(chip, pwm);
631 else
632 pwm_samsung_enable(chip, pwm);
633 }
634
635 return 0;
636}
637#endif
638
639static SIMPLE_DEV_PM_OPS(pwm_samsung_pm_ops, NULL, pwm_samsung_resume);
640
641static struct platform_driver pwm_samsung_driver = {
642 .driver = {
643 .name = "samsung-pwm",
644 .pm = &pwm_samsung_pm_ops,
645 .of_match_table = of_match_ptr(samsung_pwm_matches),
646 },
647 .probe = pwm_samsung_probe,
648 .remove = pwm_samsung_remove,
649};
650module_platform_driver(pwm_samsung_driver);
651
652MODULE_LICENSE("GPL");
653MODULE_AUTHOR("Tomasz Figa <tomasz.figa@gmail.com>");
654MODULE_ALIAS("platform:samsung-pwm");
1/*
2 * Copyright (c) 2007 Ben Dooks
3 * Copyright (c) 2008 Simtec Electronics
4 * Ben Dooks <ben@simtec.co.uk>, <ben-linux@fluff.org>
5 * Copyright (c) 2013 Tomasz Figa <tomasz.figa@gmail.com>
6 *
7 * PWM driver for Samsung SoCs
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License.
12 */
13
14#include <linux/bitops.h>
15#include <linux/clk.h>
16#include <linux/export.h>
17#include <linux/err.h>
18#include <linux/io.h>
19#include <linux/kernel.h>
20#include <linux/module.h>
21#include <linux/of.h>
22#include <linux/platform_device.h>
23#include <linux/pwm.h>
24#include <linux/slab.h>
25#include <linux/spinlock.h>
26#include <linux/time.h>
27
28/* For struct samsung_timer_variant and samsung_pwm_lock. */
29#include <clocksource/samsung_pwm.h>
30
31#define REG_TCFG0 0x00
32#define REG_TCFG1 0x04
33#define REG_TCON 0x08
34
35#define REG_TCNTB(chan) (0x0c + ((chan) * 0xc))
36#define REG_TCMPB(chan) (0x10 + ((chan) * 0xc))
37
38#define TCFG0_PRESCALER_MASK 0xff
39#define TCFG0_PRESCALER1_SHIFT 8
40
41#define TCFG1_MUX_MASK 0xf
42#define TCFG1_SHIFT(chan) (4 * (chan))
43
44/*
45 * Each channel occupies 4 bits in TCON register, but there is a gap of 4
46 * bits (one channel) after channel 0, so channels have different numbering
47 * when accessing TCON register. See to_tcon_channel() function.
48 *
49 * In addition, the location of autoreload bit for channel 4 (TCON channel 5)
50 * in its set of bits is 2 as opposed to 3 for other channels.
51 */
52#define TCON_START(chan) BIT(4 * (chan) + 0)
53#define TCON_MANUALUPDATE(chan) BIT(4 * (chan) + 1)
54#define TCON_INVERT(chan) BIT(4 * (chan) + 2)
55#define _TCON_AUTORELOAD(chan) BIT(4 * (chan) + 3)
56#define _TCON_AUTORELOAD4(chan) BIT(4 * (chan) + 2)
57#define TCON_AUTORELOAD(chan) \
58 ((chan < 5) ? _TCON_AUTORELOAD(chan) : _TCON_AUTORELOAD4(chan))
59
60/**
61 * struct samsung_pwm_channel - private data of PWM channel
62 * @period_ns: current period in nanoseconds programmed to the hardware
63 * @duty_ns: current duty time in nanoseconds programmed to the hardware
64 * @tin_ns: time of one timer tick in nanoseconds with current timer rate
65 */
66struct samsung_pwm_channel {
67 u32 period_ns;
68 u32 duty_ns;
69 u32 tin_ns;
70};
71
72/**
73 * struct samsung_pwm_chip - private data of PWM chip
74 * @chip: generic PWM chip
75 * @variant: local copy of hardware variant data
76 * @inverter_mask: inverter status for all channels - one bit per channel
77 * @base: base address of mapped PWM registers
78 * @base_clk: base clock used to drive the timers
79 * @tclk0: external clock 0 (can be ERR_PTR if not present)
80 * @tclk1: external clock 1 (can be ERR_PTR if not present)
81 */
82struct samsung_pwm_chip {
83 struct pwm_chip chip;
84 struct samsung_pwm_variant variant;
85 u8 inverter_mask;
86
87 void __iomem *base;
88 struct clk *base_clk;
89 struct clk *tclk0;
90 struct clk *tclk1;
91};
92
93#ifndef CONFIG_CLKSRC_SAMSUNG_PWM
94/*
95 * PWM block is shared between pwm-samsung and samsung_pwm_timer drivers
96 * and some registers need access synchronization. If both drivers are
97 * compiled in, the spinlock is defined in the clocksource driver,
98 * otherwise following definition is used.
99 *
100 * Currently we do not need any more complex synchronization method
101 * because all the supported SoCs contain only one instance of the PWM
102 * IP. Should this change, both drivers will need to be modified to
103 * properly synchronize accesses to particular instances.
104 */
105static DEFINE_SPINLOCK(samsung_pwm_lock);
106#endif
107
108static inline
109struct samsung_pwm_chip *to_samsung_pwm_chip(struct pwm_chip *chip)
110{
111 return container_of(chip, struct samsung_pwm_chip, chip);
112}
113
114static inline unsigned int to_tcon_channel(unsigned int channel)
115{
116 /* TCON register has a gap of 4 bits (1 channel) after channel 0 */
117 return (channel == 0) ? 0 : (channel + 1);
118}
119
120static void pwm_samsung_set_divisor(struct samsung_pwm_chip *pwm,
121 unsigned int channel, u8 divisor)
122{
123 u8 shift = TCFG1_SHIFT(channel);
124 unsigned long flags;
125 u32 reg;
126 u8 bits;
127
128 bits = (fls(divisor) - 1) - pwm->variant.div_base;
129
130 spin_lock_irqsave(&samsung_pwm_lock, flags);
131
132 reg = readl(pwm->base + REG_TCFG1);
133 reg &= ~(TCFG1_MUX_MASK << shift);
134 reg |= bits << shift;
135 writel(reg, pwm->base + REG_TCFG1);
136
137 spin_unlock_irqrestore(&samsung_pwm_lock, flags);
138}
139
140static int pwm_samsung_is_tdiv(struct samsung_pwm_chip *chip, unsigned int chan)
141{
142 struct samsung_pwm_variant *variant = &chip->variant;
143 u32 reg;
144
145 reg = readl(chip->base + REG_TCFG1);
146 reg >>= TCFG1_SHIFT(chan);
147 reg &= TCFG1_MUX_MASK;
148
149 return (BIT(reg) & variant->tclk_mask) == 0;
150}
151
152static unsigned long pwm_samsung_get_tin_rate(struct samsung_pwm_chip *chip,
153 unsigned int chan)
154{
155 unsigned long rate;
156 u32 reg;
157
158 rate = clk_get_rate(chip->base_clk);
159
160 reg = readl(chip->base + REG_TCFG0);
161 if (chan >= 2)
162 reg >>= TCFG0_PRESCALER1_SHIFT;
163 reg &= TCFG0_PRESCALER_MASK;
164
165 return rate / (reg + 1);
166}
167
168static unsigned long pwm_samsung_calc_tin(struct samsung_pwm_chip *chip,
169 unsigned int chan, unsigned long freq)
170{
171 struct samsung_pwm_variant *variant = &chip->variant;
172 unsigned long rate;
173 struct clk *clk;
174 u8 div;
175
176 if (!pwm_samsung_is_tdiv(chip, chan)) {
177 clk = (chan < 2) ? chip->tclk0 : chip->tclk1;
178 if (!IS_ERR(clk)) {
179 rate = clk_get_rate(clk);
180 if (rate)
181 return rate;
182 }
183
184 dev_warn(chip->chip.dev,
185 "tclk of PWM %d is inoperational, using tdiv\n", chan);
186 }
187
188 rate = pwm_samsung_get_tin_rate(chip, chan);
189 dev_dbg(chip->chip.dev, "tin parent at %lu\n", rate);
190
191 /*
192 * Compare minimum PWM frequency that can be achieved with possible
193 * divider settings and choose the lowest divisor that can generate
194 * frequencies lower than requested.
195 */
196 for (div = variant->div_base; div < 4; ++div)
197 if ((rate >> (variant->bits + div)) < freq)
198 break;
199
200 pwm_samsung_set_divisor(chip, chan, BIT(div));
201
202 return rate >> div;
203}
204
205static int pwm_samsung_request(struct pwm_chip *chip, struct pwm_device *pwm)
206{
207 struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
208 struct samsung_pwm_channel *our_chan;
209
210 if (!(our_chip->variant.output_mask & BIT(pwm->hwpwm))) {
211 dev_warn(chip->dev,
212 "tried to request PWM channel %d without output\n",
213 pwm->hwpwm);
214 return -EINVAL;
215 }
216
217 our_chan = devm_kzalloc(chip->dev, sizeof(*our_chan), GFP_KERNEL);
218 if (!our_chan)
219 return -ENOMEM;
220
221 pwm_set_chip_data(pwm, our_chan);
222
223 return 0;
224}
225
226static void pwm_samsung_free(struct pwm_chip *chip, struct pwm_device *pwm)
227{
228 devm_kfree(chip->dev, pwm_get_chip_data(pwm));
229 pwm_set_chip_data(pwm, NULL);
230}
231
232static int pwm_samsung_enable(struct pwm_chip *chip, struct pwm_device *pwm)
233{
234 struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
235 unsigned int tcon_chan = to_tcon_channel(pwm->hwpwm);
236 unsigned long flags;
237 u32 tcon;
238
239 spin_lock_irqsave(&samsung_pwm_lock, flags);
240
241 tcon = readl(our_chip->base + REG_TCON);
242
243 tcon &= ~TCON_START(tcon_chan);
244 tcon |= TCON_MANUALUPDATE(tcon_chan);
245 writel(tcon, our_chip->base + REG_TCON);
246
247 tcon &= ~TCON_MANUALUPDATE(tcon_chan);
248 tcon |= TCON_START(tcon_chan) | TCON_AUTORELOAD(tcon_chan);
249 writel(tcon, our_chip->base + REG_TCON);
250
251 spin_unlock_irqrestore(&samsung_pwm_lock, flags);
252
253 return 0;
254}
255
256static void pwm_samsung_disable(struct pwm_chip *chip, struct pwm_device *pwm)
257{
258 struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
259 unsigned int tcon_chan = to_tcon_channel(pwm->hwpwm);
260 unsigned long flags;
261 u32 tcon;
262
263 spin_lock_irqsave(&samsung_pwm_lock, flags);
264
265 tcon = readl(our_chip->base + REG_TCON);
266 tcon &= ~TCON_AUTORELOAD(tcon_chan);
267 writel(tcon, our_chip->base + REG_TCON);
268
269 spin_unlock_irqrestore(&samsung_pwm_lock, flags);
270}
271
272static void pwm_samsung_manual_update(struct samsung_pwm_chip *chip,
273 struct pwm_device *pwm)
274{
275 unsigned int tcon_chan = to_tcon_channel(pwm->hwpwm);
276 u32 tcon;
277 unsigned long flags;
278
279 spin_lock_irqsave(&samsung_pwm_lock, flags);
280
281 tcon = readl(chip->base + REG_TCON);
282 tcon |= TCON_MANUALUPDATE(tcon_chan);
283 writel(tcon, chip->base + REG_TCON);
284
285 tcon &= ~TCON_MANUALUPDATE(tcon_chan);
286 writel(tcon, chip->base + REG_TCON);
287
288 spin_unlock_irqrestore(&samsung_pwm_lock, flags);
289}
290
291static int pwm_samsung_config(struct pwm_chip *chip, struct pwm_device *pwm,
292 int duty_ns, int period_ns)
293{
294 struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
295 struct samsung_pwm_channel *chan = pwm_get_chip_data(pwm);
296 u32 tin_ns = chan->tin_ns, tcnt, tcmp, oldtcmp;
297
298 /*
299 * We currently avoid using 64bit arithmetic by using the
300 * fact that anything faster than 1Hz is easily representable
301 * by 32bits.
302 */
303 if (period_ns > NSEC_PER_SEC)
304 return -ERANGE;
305
306 if (period_ns == chan->period_ns && duty_ns == chan->duty_ns)
307 return 0;
308
309 tcnt = readl(our_chip->base + REG_TCNTB(pwm->hwpwm));
310 oldtcmp = readl(our_chip->base + REG_TCMPB(pwm->hwpwm));
311
312 /* We need tick count for calculation, not last tick. */
313 ++tcnt;
314
315 /* Check to see if we are changing the clock rate of the PWM. */
316 if (chan->period_ns != period_ns) {
317 unsigned long tin_rate;
318 u32 period;
319
320 period = NSEC_PER_SEC / period_ns;
321
322 dev_dbg(our_chip->chip.dev, "duty_ns=%d, period_ns=%d (%u)\n",
323 duty_ns, period_ns, period);
324
325 tin_rate = pwm_samsung_calc_tin(our_chip, pwm->hwpwm, period);
326
327 dev_dbg(our_chip->chip.dev, "tin_rate=%lu\n", tin_rate);
328
329 tin_ns = NSEC_PER_SEC / tin_rate;
330 tcnt = period_ns / tin_ns;
331 }
332
333 /* Period is too short. */
334 if (tcnt <= 1)
335 return -ERANGE;
336
337 /* Note that counters count down. */
338 tcmp = duty_ns / tin_ns;
339
340 /* 0% duty is not available */
341 if (!tcmp)
342 ++tcmp;
343
344 tcmp = tcnt - tcmp;
345
346 /* Decrement to get tick numbers, instead of tick counts. */
347 --tcnt;
348 /* -1UL will give 100% duty. */
349 --tcmp;
350
351 dev_dbg(our_chip->chip.dev,
352 "tin_ns=%u, tcmp=%u/%u\n", tin_ns, tcmp, tcnt);
353
354 /* Update PWM registers. */
355 writel(tcnt, our_chip->base + REG_TCNTB(pwm->hwpwm));
356 writel(tcmp, our_chip->base + REG_TCMPB(pwm->hwpwm));
357
358 /*
359 * In case the PWM is currently at 100% duty cycle, force a manual
360 * update to prevent the signal staying high if the PWM is disabled
361 * shortly afer this update (before it autoreloaded the new values).
362 */
363 if (oldtcmp == (u32) -1) {
364 dev_dbg(our_chip->chip.dev, "Forcing manual update");
365 pwm_samsung_manual_update(our_chip, pwm);
366 }
367
368 chan->period_ns = period_ns;
369 chan->tin_ns = tin_ns;
370 chan->duty_ns = duty_ns;
371
372 return 0;
373}
374
375static void pwm_samsung_set_invert(struct samsung_pwm_chip *chip,
376 unsigned int channel, bool invert)
377{
378 unsigned int tcon_chan = to_tcon_channel(channel);
379 unsigned long flags;
380 u32 tcon;
381
382 spin_lock_irqsave(&samsung_pwm_lock, flags);
383
384 tcon = readl(chip->base + REG_TCON);
385
386 if (invert) {
387 chip->inverter_mask |= BIT(channel);
388 tcon |= TCON_INVERT(tcon_chan);
389 } else {
390 chip->inverter_mask &= ~BIT(channel);
391 tcon &= ~TCON_INVERT(tcon_chan);
392 }
393
394 writel(tcon, chip->base + REG_TCON);
395
396 spin_unlock_irqrestore(&samsung_pwm_lock, flags);
397}
398
399static int pwm_samsung_set_polarity(struct pwm_chip *chip,
400 struct pwm_device *pwm,
401 enum pwm_polarity polarity)
402{
403 struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
404 bool invert = (polarity == PWM_POLARITY_NORMAL);
405
406 /* Inverted means normal in the hardware. */
407 pwm_samsung_set_invert(our_chip, pwm->hwpwm, invert);
408
409 return 0;
410}
411
412static const struct pwm_ops pwm_samsung_ops = {
413 .request = pwm_samsung_request,
414 .free = pwm_samsung_free,
415 .enable = pwm_samsung_enable,
416 .disable = pwm_samsung_disable,
417 .config = pwm_samsung_config,
418 .set_polarity = pwm_samsung_set_polarity,
419 .owner = THIS_MODULE,
420};
421
422#ifdef CONFIG_OF
423static const struct samsung_pwm_variant s3c24xx_variant = {
424 .bits = 16,
425 .div_base = 1,
426 .has_tint_cstat = false,
427 .tclk_mask = BIT(4),
428};
429
430static const struct samsung_pwm_variant s3c64xx_variant = {
431 .bits = 32,
432 .div_base = 0,
433 .has_tint_cstat = true,
434 .tclk_mask = BIT(7) | BIT(6) | BIT(5),
435};
436
437static const struct samsung_pwm_variant s5p64x0_variant = {
438 .bits = 32,
439 .div_base = 0,
440 .has_tint_cstat = true,
441 .tclk_mask = 0,
442};
443
444static const struct samsung_pwm_variant s5pc100_variant = {
445 .bits = 32,
446 .div_base = 0,
447 .has_tint_cstat = true,
448 .tclk_mask = BIT(5),
449};
450
451static const struct of_device_id samsung_pwm_matches[] = {
452 { .compatible = "samsung,s3c2410-pwm", .data = &s3c24xx_variant },
453 { .compatible = "samsung,s3c6400-pwm", .data = &s3c64xx_variant },
454 { .compatible = "samsung,s5p6440-pwm", .data = &s5p64x0_variant },
455 { .compatible = "samsung,s5pc100-pwm", .data = &s5pc100_variant },
456 { .compatible = "samsung,exynos4210-pwm", .data = &s5p64x0_variant },
457 {},
458};
459MODULE_DEVICE_TABLE(of, samsung_pwm_matches);
460
461static int pwm_samsung_parse_dt(struct samsung_pwm_chip *chip)
462{
463 struct device_node *np = chip->chip.dev->of_node;
464 const struct of_device_id *match;
465 struct property *prop;
466 const __be32 *cur;
467 u32 val;
468
469 match = of_match_node(samsung_pwm_matches, np);
470 if (!match)
471 return -ENODEV;
472
473 memcpy(&chip->variant, match->data, sizeof(chip->variant));
474
475 of_property_for_each_u32(np, "samsung,pwm-outputs", prop, cur, val) {
476 if (val >= SAMSUNG_PWM_NUM) {
477 dev_err(chip->chip.dev,
478 "%s: invalid channel index in samsung,pwm-outputs property\n",
479 __func__);
480 continue;
481 }
482 chip->variant.output_mask |= BIT(val);
483 }
484
485 return 0;
486}
487#else
488static int pwm_samsung_parse_dt(struct samsung_pwm_chip *chip)
489{
490 return -ENODEV;
491}
492#endif
493
494static int pwm_samsung_probe(struct platform_device *pdev)
495{
496 struct device *dev = &pdev->dev;
497 struct samsung_pwm_chip *chip;
498 struct resource *res;
499 unsigned int chan;
500 int ret;
501
502 chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
503 if (chip == NULL)
504 return -ENOMEM;
505
506 chip->chip.dev = &pdev->dev;
507 chip->chip.ops = &pwm_samsung_ops;
508 chip->chip.base = -1;
509 chip->chip.npwm = SAMSUNG_PWM_NUM;
510 chip->inverter_mask = BIT(SAMSUNG_PWM_NUM) - 1;
511
512 if (IS_ENABLED(CONFIG_OF) && pdev->dev.of_node) {
513 ret = pwm_samsung_parse_dt(chip);
514 if (ret)
515 return ret;
516
517 chip->chip.of_xlate = of_pwm_xlate_with_flags;
518 chip->chip.of_pwm_n_cells = 3;
519 } else {
520 if (!pdev->dev.platform_data) {
521 dev_err(&pdev->dev, "no platform data specified\n");
522 return -EINVAL;
523 }
524
525 memcpy(&chip->variant, pdev->dev.platform_data,
526 sizeof(chip->variant));
527 }
528
529 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
530 chip->base = devm_ioremap_resource(&pdev->dev, res);
531 if (IS_ERR(chip->base))
532 return PTR_ERR(chip->base);
533
534 chip->base_clk = devm_clk_get(&pdev->dev, "timers");
535 if (IS_ERR(chip->base_clk)) {
536 dev_err(dev, "failed to get timer base clk\n");
537 return PTR_ERR(chip->base_clk);
538 }
539
540 ret = clk_prepare_enable(chip->base_clk);
541 if (ret < 0) {
542 dev_err(dev, "failed to enable base clock\n");
543 return ret;
544 }
545
546 for (chan = 0; chan < SAMSUNG_PWM_NUM; ++chan)
547 if (chip->variant.output_mask & BIT(chan))
548 pwm_samsung_set_invert(chip, chan, true);
549
550 /* Following clocks are optional. */
551 chip->tclk0 = devm_clk_get(&pdev->dev, "pwm-tclk0");
552 chip->tclk1 = devm_clk_get(&pdev->dev, "pwm-tclk1");
553
554 platform_set_drvdata(pdev, chip);
555
556 ret = pwmchip_add(&chip->chip);
557 if (ret < 0) {
558 dev_err(dev, "failed to register PWM chip\n");
559 clk_disable_unprepare(chip->base_clk);
560 return ret;
561 }
562
563 dev_dbg(dev, "base_clk at %lu, tclk0 at %lu, tclk1 at %lu\n",
564 clk_get_rate(chip->base_clk),
565 !IS_ERR(chip->tclk0) ? clk_get_rate(chip->tclk0) : 0,
566 !IS_ERR(chip->tclk1) ? clk_get_rate(chip->tclk1) : 0);
567
568 return 0;
569}
570
571static int pwm_samsung_remove(struct platform_device *pdev)
572{
573 struct samsung_pwm_chip *chip = platform_get_drvdata(pdev);
574 int ret;
575
576 ret = pwmchip_remove(&chip->chip);
577 if (ret < 0)
578 return ret;
579
580 clk_disable_unprepare(chip->base_clk);
581
582 return 0;
583}
584
585#ifdef CONFIG_PM_SLEEP
586static int pwm_samsung_suspend(struct device *dev)
587{
588 struct samsung_pwm_chip *chip = dev_get_drvdata(dev);
589 unsigned int i;
590
591 /*
592 * No one preserves these values during suspend so reset them.
593 * Otherwise driver leaves PWM unconfigured if same values are
594 * passed to pwm_config() next time.
595 */
596 for (i = 0; i < SAMSUNG_PWM_NUM; ++i) {
597 struct pwm_device *pwm = &chip->chip.pwms[i];
598 struct samsung_pwm_channel *chan = pwm_get_chip_data(pwm);
599
600 if (!chan)
601 continue;
602
603 chan->period_ns = 0;
604 chan->duty_ns = 0;
605 }
606
607 return 0;
608}
609
610static int pwm_samsung_resume(struct device *dev)
611{
612 struct samsung_pwm_chip *chip = dev_get_drvdata(dev);
613 unsigned int chan;
614
615 /*
616 * Inverter setting must be preserved across suspend/resume
617 * as nobody really seems to configure it more than once.
618 */
619 for (chan = 0; chan < SAMSUNG_PWM_NUM; ++chan) {
620 if (chip->variant.output_mask & BIT(chan))
621 pwm_samsung_set_invert(chip, chan,
622 chip->inverter_mask & BIT(chan));
623 }
624
625 return 0;
626}
627#endif
628
629static SIMPLE_DEV_PM_OPS(pwm_samsung_pm_ops, pwm_samsung_suspend,
630 pwm_samsung_resume);
631
632static struct platform_driver pwm_samsung_driver = {
633 .driver = {
634 .name = "samsung-pwm",
635 .pm = &pwm_samsung_pm_ops,
636 .of_match_table = of_match_ptr(samsung_pwm_matches),
637 },
638 .probe = pwm_samsung_probe,
639 .remove = pwm_samsung_remove,
640};
641module_platform_driver(pwm_samsung_driver);
642
643MODULE_LICENSE("GPL");
644MODULE_AUTHOR("Tomasz Figa <tomasz.figa@gmail.com>");
645MODULE_ALIAS("platform:samsung-pwm");