1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (c) 2007 Ben Dooks
4 * Copyright (c) 2008 Simtec Electronics
5 * Ben Dooks <ben@simtec.co.uk>, <ben-linux@fluff.org>
6 * Copyright (c) 2013 Tomasz Figa <tomasz.figa@gmail.com>
7 * Copyright (c) 2017 Samsung Electronics Co., Ltd.
9 * PWM driver for Samsung SoCs
12 #include <linux/bitops.h>
13 #include <linux/clk.h>
14 #include <linux/export.h>
15 #include <linux/err.h>
17 #include <linux/kernel.h>
18 #include <linux/module.h>
20 #include <linux/platform_device.h>
21 #include <linux/pwm.h>
22 #include <linux/slab.h>
23 #include <linux/spinlock.h>
24 #include <linux/time.h>
26 /* For struct samsung_timer_variant and samsung_pwm_lock. */
27 #include <clocksource/samsung_pwm.h>
29 #define REG_TCFG0 0x00
30 #define REG_TCFG1 0x04
33 #define REG_TCNTB(chan) (0x0c + ((chan) * 0xc))
34 #define REG_TCMPB(chan) (0x10 + ((chan) * 0xc))
36 #define TCFG0_PRESCALER_MASK 0xff
37 #define TCFG0_PRESCALER1_SHIFT 8
39 #define TCFG1_MUX_MASK 0xf
40 #define TCFG1_SHIFT(chan) (4 * (chan))
43 * Each channel occupies 4 bits in TCON register, but there is a gap of 4
44 * bits (one channel) after channel 0, so channels have different numbering
45 * when accessing TCON register. See to_tcon_channel() function.
47 * In addition, the location of autoreload bit for channel 4 (TCON channel 5)
48 * in its set of bits is 2 as opposed to 3 for other channels.
50 #define TCON_START(chan) BIT(4 * (chan) + 0)
51 #define TCON_MANUALUPDATE(chan) BIT(4 * (chan) + 1)
52 #define TCON_INVERT(chan) BIT(4 * (chan) + 2)
53 #define _TCON_AUTORELOAD(chan) BIT(4 * (chan) + 3)
54 #define _TCON_AUTORELOAD4(chan) BIT(4 * (chan) + 2)
55 #define TCON_AUTORELOAD(chan) \
56 ((chan < 5) ? _TCON_AUTORELOAD(chan) : _TCON_AUTORELOAD4(chan))
59 * struct samsung_pwm_channel - private data of PWM channel
60 * @period_ns: current period in nanoseconds programmed to the hardware
61 * @duty_ns: current duty time in nanoseconds programmed to the hardware
62 * @tin_ns: time of one timer tick in nanoseconds with current timer rate
64 struct samsung_pwm_channel {
71 * struct samsung_pwm_chip - private data of PWM chip
72 * @chip: generic PWM chip
73 * @variant: local copy of hardware variant data
74 * @inverter_mask: inverter status for all channels - one bit per channel
75 * @disabled_mask: disabled status for all channels - one bit per channel
76 * @base: base address of mapped PWM registers
77 * @base_clk: base clock used to drive the timers
78 * @tclk0: external clock 0 (can be ERR_PTR if not present)
79 * @tclk1: external clock 1 (can be ERR_PTR if not present)
81 struct samsung_pwm_chip {
83 struct samsung_pwm_variant variant;
93 #ifndef CONFIG_CLKSRC_SAMSUNG_PWM
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.
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.
105 static DEFINE_SPINLOCK(samsung_pwm_lock);
109 struct samsung_pwm_chip *to_samsung_pwm_chip(struct pwm_chip *chip)
111 return container_of(chip, struct samsung_pwm_chip, chip);
114 static inline unsigned int to_tcon_channel(unsigned int channel)
116 /* TCON register has a gap of 4 bits (1 channel) after channel 0 */
117 return (channel == 0) ? 0 : (channel + 1);
120 static void pwm_samsung_set_divisor(struct samsung_pwm_chip *pwm,
121 unsigned int channel, u8 divisor)
123 u8 shift = TCFG1_SHIFT(channel);
128 bits = (fls(divisor) - 1) - pwm->variant.div_base;
130 spin_lock_irqsave(&samsung_pwm_lock, flags);
132 reg = readl(pwm->base + REG_TCFG1);
133 reg &= ~(TCFG1_MUX_MASK << shift);
134 reg |= bits << shift;
135 writel(reg, pwm->base + REG_TCFG1);
137 spin_unlock_irqrestore(&samsung_pwm_lock, flags);
140 static int pwm_samsung_is_tdiv(struct samsung_pwm_chip *chip, unsigned int chan)
142 struct samsung_pwm_variant *variant = &chip->variant;
145 reg = readl(chip->base + REG_TCFG1);
146 reg >>= TCFG1_SHIFT(chan);
147 reg &= TCFG1_MUX_MASK;
149 return (BIT(reg) & variant->tclk_mask) == 0;
152 static unsigned long pwm_samsung_get_tin_rate(struct samsung_pwm_chip *chip,
158 rate = clk_get_rate(chip->base_clk);
160 reg = readl(chip->base + REG_TCFG0);
162 reg >>= TCFG0_PRESCALER1_SHIFT;
163 reg &= TCFG0_PRESCALER_MASK;
165 return rate / (reg + 1);
168 static unsigned long pwm_samsung_calc_tin(struct samsung_pwm_chip *chip,
169 unsigned int chan, unsigned long freq)
171 struct samsung_pwm_variant *variant = &chip->variant;
176 if (!pwm_samsung_is_tdiv(chip, chan)) {
177 clk = (chan < 2) ? chip->tclk0 : chip->tclk1;
179 rate = clk_get_rate(clk);
184 dev_warn(chip->chip.dev,
185 "tclk of PWM %d is inoperational, using tdiv\n", chan);
188 rate = pwm_samsung_get_tin_rate(chip, chan);
189 dev_dbg(chip->chip.dev, "tin parent at %lu\n", rate);
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.
196 if (variant->bits < 32) {
197 /* Only for s3c24xx */
198 for (div = variant->div_base; div < 4; ++div)
199 if ((rate >> (variant->bits + div)) < freq)
203 * Other variants have enough counter bits to generate any
204 * requested rate, so no need to check higher divisors.
206 div = variant->div_base;
209 pwm_samsung_set_divisor(chip, chan, BIT(div));
214 static int pwm_samsung_request(struct pwm_chip *chip, struct pwm_device *pwm)
216 struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
217 struct samsung_pwm_channel *our_chan;
219 if (!(our_chip->variant.output_mask & BIT(pwm->hwpwm))) {
221 "tried to request PWM channel %d without output\n",
226 our_chan = kzalloc(sizeof(*our_chan), GFP_KERNEL);
230 pwm_set_chip_data(pwm, our_chan);
235 static void pwm_samsung_free(struct pwm_chip *chip, struct pwm_device *pwm)
237 kfree(pwm_get_chip_data(pwm));
240 static int pwm_samsung_enable(struct pwm_chip *chip, struct pwm_device *pwm)
242 struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
243 unsigned int tcon_chan = to_tcon_channel(pwm->hwpwm);
247 spin_lock_irqsave(&samsung_pwm_lock, flags);
249 tcon = readl(our_chip->base + REG_TCON);
251 tcon &= ~TCON_START(tcon_chan);
252 tcon |= TCON_MANUALUPDATE(tcon_chan);
253 writel(tcon, our_chip->base + REG_TCON);
255 tcon &= ~TCON_MANUALUPDATE(tcon_chan);
256 tcon |= TCON_START(tcon_chan) | TCON_AUTORELOAD(tcon_chan);
257 writel(tcon, our_chip->base + REG_TCON);
259 our_chip->disabled_mask &= ~BIT(pwm->hwpwm);
261 spin_unlock_irqrestore(&samsung_pwm_lock, flags);
266 static void pwm_samsung_disable(struct pwm_chip *chip, struct pwm_device *pwm)
268 struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
269 unsigned int tcon_chan = to_tcon_channel(pwm->hwpwm);
273 spin_lock_irqsave(&samsung_pwm_lock, flags);
275 tcon = readl(our_chip->base + REG_TCON);
276 tcon &= ~TCON_AUTORELOAD(tcon_chan);
277 writel(tcon, our_chip->base + REG_TCON);
279 our_chip->disabled_mask |= BIT(pwm->hwpwm);
281 spin_unlock_irqrestore(&samsung_pwm_lock, flags);
284 static void pwm_samsung_manual_update(struct samsung_pwm_chip *chip,
285 struct pwm_device *pwm)
287 unsigned int tcon_chan = to_tcon_channel(pwm->hwpwm);
291 spin_lock_irqsave(&samsung_pwm_lock, flags);
293 tcon = readl(chip->base + REG_TCON);
294 tcon |= TCON_MANUALUPDATE(tcon_chan);
295 writel(tcon, chip->base + REG_TCON);
297 tcon &= ~TCON_MANUALUPDATE(tcon_chan);
298 writel(tcon, chip->base + REG_TCON);
300 spin_unlock_irqrestore(&samsung_pwm_lock, flags);
303 static int __pwm_samsung_config(struct pwm_chip *chip, struct pwm_device *pwm,
304 int duty_ns, int period_ns, bool force_period)
306 struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
307 struct samsung_pwm_channel *chan = pwm_get_chip_data(pwm);
308 u32 tin_ns = chan->tin_ns, tcnt, tcmp, oldtcmp;
311 * We currently avoid using 64bit arithmetic by using the
312 * fact that anything faster than 1Hz is easily representable
315 if (period_ns > NSEC_PER_SEC)
318 tcnt = readl(our_chip->base + REG_TCNTB(pwm->hwpwm));
319 oldtcmp = readl(our_chip->base + REG_TCMPB(pwm->hwpwm));
321 /* We need tick count for calculation, not last tick. */
324 /* Check to see if we are changing the clock rate of the PWM. */
325 if (chan->period_ns != period_ns || force_period) {
326 unsigned long tin_rate;
329 period = NSEC_PER_SEC / period_ns;
331 dev_dbg(our_chip->chip.dev, "duty_ns=%d, period_ns=%d (%u)\n",
332 duty_ns, period_ns, period);
334 tin_rate = pwm_samsung_calc_tin(our_chip, pwm->hwpwm, period);
336 dev_dbg(our_chip->chip.dev, "tin_rate=%lu\n", tin_rate);
338 tin_ns = NSEC_PER_SEC / tin_rate;
339 tcnt = period_ns / tin_ns;
342 /* Period is too short. */
346 /* Note that counters count down. */
347 tcmp = duty_ns / tin_ns;
349 /* 0% duty is not available */
355 /* Decrement to get tick numbers, instead of tick counts. */
357 /* -1UL will give 100% duty. */
360 dev_dbg(our_chip->chip.dev,
361 "tin_ns=%u, tcmp=%u/%u\n", tin_ns, tcmp, tcnt);
363 /* Update PWM registers. */
364 writel(tcnt, our_chip->base + REG_TCNTB(pwm->hwpwm));
365 writel(tcmp, our_chip->base + REG_TCMPB(pwm->hwpwm));
368 * In case the PWM is currently at 100% duty cycle, force a manual
369 * update to prevent the signal staying high if the PWM is disabled
370 * shortly afer this update (before it autoreloaded the new values).
372 if (oldtcmp == (u32) -1) {
373 dev_dbg(our_chip->chip.dev, "Forcing manual update");
374 pwm_samsung_manual_update(our_chip, pwm);
377 chan->period_ns = period_ns;
378 chan->tin_ns = tin_ns;
379 chan->duty_ns = duty_ns;
384 static int pwm_samsung_config(struct pwm_chip *chip, struct pwm_device *pwm,
385 int duty_ns, int period_ns)
387 return __pwm_samsung_config(chip, pwm, duty_ns, period_ns, false);
390 static void pwm_samsung_set_invert(struct samsung_pwm_chip *chip,
391 unsigned int channel, bool invert)
393 unsigned int tcon_chan = to_tcon_channel(channel);
397 spin_lock_irqsave(&samsung_pwm_lock, flags);
399 tcon = readl(chip->base + REG_TCON);
402 chip->inverter_mask |= BIT(channel);
403 tcon |= TCON_INVERT(tcon_chan);
405 chip->inverter_mask &= ~BIT(channel);
406 tcon &= ~TCON_INVERT(tcon_chan);
409 writel(tcon, chip->base + REG_TCON);
411 spin_unlock_irqrestore(&samsung_pwm_lock, flags);
414 static int pwm_samsung_set_polarity(struct pwm_chip *chip,
415 struct pwm_device *pwm,
416 enum pwm_polarity polarity)
418 struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
419 bool invert = (polarity == PWM_POLARITY_NORMAL);
421 /* Inverted means normal in the hardware. */
422 pwm_samsung_set_invert(our_chip, pwm->hwpwm, invert);
427 static const struct pwm_ops pwm_samsung_ops = {
428 .request = pwm_samsung_request,
429 .free = pwm_samsung_free,
430 .enable = pwm_samsung_enable,
431 .disable = pwm_samsung_disable,
432 .config = pwm_samsung_config,
433 .set_polarity = pwm_samsung_set_polarity,
434 .owner = THIS_MODULE,
438 static const struct samsung_pwm_variant s3c24xx_variant = {
441 .has_tint_cstat = false,
445 static const struct samsung_pwm_variant s3c64xx_variant = {
448 .has_tint_cstat = true,
449 .tclk_mask = BIT(7) | BIT(6) | BIT(5),
452 static const struct samsung_pwm_variant s5p64x0_variant = {
455 .has_tint_cstat = true,
459 static const struct samsung_pwm_variant s5pc100_variant = {
462 .has_tint_cstat = true,
466 static const struct of_device_id samsung_pwm_matches[] = {
467 { .compatible = "samsung,s3c2410-pwm", .data = &s3c24xx_variant },
468 { .compatible = "samsung,s3c6400-pwm", .data = &s3c64xx_variant },
469 { .compatible = "samsung,s5p6440-pwm", .data = &s5p64x0_variant },
470 { .compatible = "samsung,s5pc100-pwm", .data = &s5pc100_variant },
471 { .compatible = "samsung,exynos4210-pwm", .data = &s5p64x0_variant },
474 MODULE_DEVICE_TABLE(of, samsung_pwm_matches);
476 static int pwm_samsung_parse_dt(struct samsung_pwm_chip *chip)
478 struct device_node *np = chip->chip.dev->of_node;
479 const struct of_device_id *match;
480 struct property *prop;
484 match = of_match_node(samsung_pwm_matches, np);
488 memcpy(&chip->variant, match->data, sizeof(chip->variant));
490 of_property_for_each_u32(np, "samsung,pwm-outputs", prop, cur, val) {
491 if (val >= SAMSUNG_PWM_NUM) {
492 dev_err(chip->chip.dev,
493 "%s: invalid channel index in samsung,pwm-outputs property\n",
497 chip->variant.output_mask |= BIT(val);
503 static int pwm_samsung_parse_dt(struct samsung_pwm_chip *chip)
509 static int pwm_samsung_probe(struct platform_device *pdev)
511 struct device *dev = &pdev->dev;
512 struct samsung_pwm_chip *chip;
516 chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
520 chip->chip.dev = &pdev->dev;
521 chip->chip.ops = &pwm_samsung_ops;
522 chip->chip.npwm = SAMSUNG_PWM_NUM;
523 chip->inverter_mask = BIT(SAMSUNG_PWM_NUM) - 1;
525 if (IS_ENABLED(CONFIG_OF) && pdev->dev.of_node) {
526 ret = pwm_samsung_parse_dt(chip);
530 if (!pdev->dev.platform_data) {
531 dev_err(&pdev->dev, "no platform data specified\n");
535 memcpy(&chip->variant, pdev->dev.platform_data,
536 sizeof(chip->variant));
539 chip->base = devm_platform_ioremap_resource(pdev, 0);
540 if (IS_ERR(chip->base))
541 return PTR_ERR(chip->base);
543 chip->base_clk = devm_clk_get(&pdev->dev, "timers");
544 if (IS_ERR(chip->base_clk)) {
545 dev_err(dev, "failed to get timer base clk\n");
546 return PTR_ERR(chip->base_clk);
549 ret = clk_prepare_enable(chip->base_clk);
551 dev_err(dev, "failed to enable base clock\n");
555 for (chan = 0; chan < SAMSUNG_PWM_NUM; ++chan)
556 if (chip->variant.output_mask & BIT(chan))
557 pwm_samsung_set_invert(chip, chan, true);
559 /* Following clocks are optional. */
560 chip->tclk0 = devm_clk_get(&pdev->dev, "pwm-tclk0");
561 chip->tclk1 = devm_clk_get(&pdev->dev, "pwm-tclk1");
563 platform_set_drvdata(pdev, chip);
565 ret = pwmchip_add(&chip->chip);
567 dev_err(dev, "failed to register PWM chip\n");
568 clk_disable_unprepare(chip->base_clk);
572 dev_dbg(dev, "base_clk at %lu, tclk0 at %lu, tclk1 at %lu\n",
573 clk_get_rate(chip->base_clk),
574 !IS_ERR(chip->tclk0) ? clk_get_rate(chip->tclk0) : 0,
575 !IS_ERR(chip->tclk1) ? clk_get_rate(chip->tclk1) : 0);
580 static int pwm_samsung_remove(struct platform_device *pdev)
582 struct samsung_pwm_chip *chip = platform_get_drvdata(pdev);
584 pwmchip_remove(&chip->chip);
586 clk_disable_unprepare(chip->base_clk);
591 #ifdef CONFIG_PM_SLEEP
592 static int pwm_samsung_resume(struct device *dev)
594 struct samsung_pwm_chip *our_chip = dev_get_drvdata(dev);
595 struct pwm_chip *chip = &our_chip->chip;
598 for (i = 0; i < SAMSUNG_PWM_NUM; i++) {
599 struct pwm_device *pwm = &chip->pwms[i];
600 struct samsung_pwm_channel *chan = pwm_get_chip_data(pwm);
605 if (our_chip->variant.output_mask & BIT(i))
606 pwm_samsung_set_invert(our_chip, i,
607 our_chip->inverter_mask & BIT(i));
609 if (chan->period_ns) {
610 __pwm_samsung_config(chip, pwm, chan->duty_ns,
611 chan->period_ns, true);
612 /* needed to make PWM disable work on Odroid-XU3 */
613 pwm_samsung_manual_update(our_chip, pwm);
616 if (our_chip->disabled_mask & BIT(i))
617 pwm_samsung_disable(chip, pwm);
619 pwm_samsung_enable(chip, pwm);
626 static SIMPLE_DEV_PM_OPS(pwm_samsung_pm_ops, NULL, pwm_samsung_resume);
628 static struct platform_driver pwm_samsung_driver = {
630 .name = "samsung-pwm",
631 .pm = &pwm_samsung_pm_ops,
632 .of_match_table = of_match_ptr(samsung_pwm_matches),
634 .probe = pwm_samsung_probe,
635 .remove = pwm_samsung_remove,
637 module_platform_driver(pwm_samsung_driver);
639 MODULE_LICENSE("GPL");
640 MODULE_AUTHOR("Tomasz Figa <tomasz.figa@gmail.com>");
641 MODULE_ALIAS("platform:samsung-pwm");