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1// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
2/*
3 * PWM controller driver for Amlogic Meson SoCs.
4 *
5 * This PWM is only a set of Gates, Dividers and Counters:
6 * PWM output is achieved by calculating a clock that permits calculating
7 * two periods (low and high). The counter then has to be set to switch after
8 * N cycles for the first half period.
9 * The hardware has no "polarity" setting. This driver reverses the period
10 * cycles (the low length is inverted with the high length) for
11 * PWM_POLARITY_INVERSED. This means that .get_state cannot read the polarity
12 * from the hardware.
13 * Setting the duty cycle will disable and re-enable the PWM output.
14 * Disabling the PWM stops the output immediately (without waiting for the
15 * current period to complete first).
16 *
17 * The public S912 (GXM) datasheet contains some documentation for this PWM
18 * controller starting on page 543:
19 * https://dl.khadas.com/Hardware/VIM2/Datasheet/S912_Datasheet_V0.220170314publicversion-Wesion.pdf
20 * An updated version of this IP block is found in S922X (G12B) SoCs. The
21 * datasheet contains the description for this IP block revision starting at
22 * page 1084:
23 * https://dn.odroid.com/S922X/ODROID-N2/Datasheet/S922X_Public_Datasheet_V0.2.pdf
24 *
25 * Copyright (c) 2016 BayLibre, SAS.
26 * Author: Neil Armstrong <narmstrong@baylibre.com>
27 * Copyright (C) 2014 Amlogic, Inc.
28 */
29
30#include <linux/bitfield.h>
31#include <linux/bits.h>
32#include <linux/clk.h>
33#include <linux/clk-provider.h>
34#include <linux/err.h>
35#include <linux/io.h>
36#include <linux/kernel.h>
37#include <linux/math64.h>
38#include <linux/module.h>
39#include <linux/of.h>
40#include <linux/platform_device.h>
41#include <linux/pwm.h>
42#include <linux/slab.h>
43#include <linux/spinlock.h>
44
45#define REG_PWM_A 0x0
46#define REG_PWM_B 0x4
47#define PWM_LOW_MASK GENMASK(15, 0)
48#define PWM_HIGH_MASK GENMASK(31, 16)
49
50#define REG_MISC_AB 0x8
51#define MISC_B_CLK_EN_SHIFT 23
52#define MISC_A_CLK_EN_SHIFT 15
53#define MISC_CLK_DIV_WIDTH 7
54#define MISC_B_CLK_DIV_SHIFT 16
55#define MISC_A_CLK_DIV_SHIFT 8
56#define MISC_B_CLK_SEL_SHIFT 6
57#define MISC_A_CLK_SEL_SHIFT 4
58#define MISC_CLK_SEL_MASK 0x3
59#define MISC_B_EN BIT(1)
60#define MISC_A_EN BIT(0)
61
62#define MESON_NUM_PWMS 2
63#define MESON_NUM_MUX_PARENTS 4
64
65static struct meson_pwm_channel_data {
66 u8 reg_offset;
67 u8 clk_sel_shift;
68 u8 clk_div_shift;
69 u8 clk_en_shift;
70 u32 pwm_en_mask;
71} meson_pwm_per_channel_data[MESON_NUM_PWMS] = {
72 {
73 .reg_offset = REG_PWM_A,
74 .clk_sel_shift = MISC_A_CLK_SEL_SHIFT,
75 .clk_div_shift = MISC_A_CLK_DIV_SHIFT,
76 .clk_en_shift = MISC_A_CLK_EN_SHIFT,
77 .pwm_en_mask = MISC_A_EN,
78 },
79 {
80 .reg_offset = REG_PWM_B,
81 .clk_sel_shift = MISC_B_CLK_SEL_SHIFT,
82 .clk_div_shift = MISC_B_CLK_DIV_SHIFT,
83 .clk_en_shift = MISC_B_CLK_EN_SHIFT,
84 .pwm_en_mask = MISC_B_EN,
85 }
86};
87
88struct meson_pwm_channel {
89 unsigned long rate;
90 unsigned int hi;
91 unsigned int lo;
92
93 struct clk_mux mux;
94 struct clk_divider div;
95 struct clk_gate gate;
96 struct clk *clk;
97};
98
99struct meson_pwm_data {
100 const char *const parent_names[MESON_NUM_MUX_PARENTS];
101 int (*channels_init)(struct pwm_chip *chip);
102};
103
104struct meson_pwm {
105 const struct meson_pwm_data *data;
106 struct meson_pwm_channel channels[MESON_NUM_PWMS];
107 void __iomem *base;
108 /*
109 * Protects register (write) access to the REG_MISC_AB register
110 * that is shared between the two PWMs.
111 */
112 spinlock_t lock;
113};
114
115static inline struct meson_pwm *to_meson_pwm(struct pwm_chip *chip)
116{
117 return pwmchip_get_drvdata(chip);
118}
119
120static int meson_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
121{
122 struct meson_pwm *meson = to_meson_pwm(chip);
123 struct meson_pwm_channel *channel = &meson->channels[pwm->hwpwm];
124 struct device *dev = pwmchip_parent(chip);
125 int err;
126
127 err = clk_prepare_enable(channel->clk);
128 if (err < 0) {
129 dev_err(dev, "failed to enable clock %s: %d\n",
130 __clk_get_name(channel->clk), err);
131 return err;
132 }
133
134 return 0;
135}
136
137static void meson_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
138{
139 struct meson_pwm *meson = to_meson_pwm(chip);
140 struct meson_pwm_channel *channel = &meson->channels[pwm->hwpwm];
141
142 clk_disable_unprepare(channel->clk);
143}
144
145static int meson_pwm_calc(struct pwm_chip *chip, struct pwm_device *pwm,
146 const struct pwm_state *state)
147{
148 struct meson_pwm *meson = to_meson_pwm(chip);
149 struct meson_pwm_channel *channel = &meson->channels[pwm->hwpwm];
150 unsigned int cnt, duty_cnt;
151 long fin_freq;
152 u64 duty, period, freq;
153
154 duty = state->duty_cycle;
155 period = state->period;
156
157 /*
158 * Note this is wrong. The result is an output wave that isn't really
159 * inverted and so is wrongly identified by .get_state as normal.
160 * Fixing this needs some care however as some machines might rely on
161 * this.
162 */
163 if (state->polarity == PWM_POLARITY_INVERSED)
164 duty = period - duty;
165
166 freq = div64_u64(NSEC_PER_SEC * 0xffffULL, period);
167 if (freq > ULONG_MAX)
168 freq = ULONG_MAX;
169
170 fin_freq = clk_round_rate(channel->clk, freq);
171 if (fin_freq <= 0) {
172 dev_err(pwmchip_parent(chip),
173 "invalid source clock frequency %llu\n", freq);
174 return fin_freq ? fin_freq : -EINVAL;
175 }
176
177 dev_dbg(pwmchip_parent(chip), "fin_freq: %ld Hz\n", fin_freq);
178
179 cnt = mul_u64_u64_div_u64(fin_freq, period, NSEC_PER_SEC);
180 if (cnt > 0xffff) {
181 dev_err(pwmchip_parent(chip), "unable to get period cnt\n");
182 return -EINVAL;
183 }
184
185 dev_dbg(pwmchip_parent(chip), "period=%llu cnt=%u\n", period, cnt);
186
187 if (duty == period) {
188 channel->hi = cnt;
189 channel->lo = 0;
190 } else if (duty == 0) {
191 channel->hi = 0;
192 channel->lo = cnt;
193 } else {
194 duty_cnt = mul_u64_u64_div_u64(fin_freq, duty, NSEC_PER_SEC);
195
196 dev_dbg(pwmchip_parent(chip), "duty=%llu duty_cnt=%u\n", duty, duty_cnt);
197
198 channel->hi = duty_cnt;
199 channel->lo = cnt - duty_cnt;
200 }
201
202 channel->rate = fin_freq;
203
204 return 0;
205}
206
207static void meson_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
208{
209 struct meson_pwm *meson = to_meson_pwm(chip);
210 struct meson_pwm_channel *channel = &meson->channels[pwm->hwpwm];
211 struct meson_pwm_channel_data *channel_data;
212 unsigned long flags;
213 u32 value;
214 int err;
215
216 channel_data = &meson_pwm_per_channel_data[pwm->hwpwm];
217
218 err = clk_set_rate(channel->clk, channel->rate);
219 if (err)
220 dev_err(pwmchip_parent(chip), "setting clock rate failed\n");
221
222 spin_lock_irqsave(&meson->lock, flags);
223
224 value = FIELD_PREP(PWM_HIGH_MASK, channel->hi) |
225 FIELD_PREP(PWM_LOW_MASK, channel->lo);
226 writel(value, meson->base + channel_data->reg_offset);
227
228 value = readl(meson->base + REG_MISC_AB);
229 value |= channel_data->pwm_en_mask;
230 writel(value, meson->base + REG_MISC_AB);
231
232 spin_unlock_irqrestore(&meson->lock, flags);
233}
234
235static void meson_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
236{
237 struct meson_pwm *meson = to_meson_pwm(chip);
238 unsigned long flags;
239 u32 value;
240
241 spin_lock_irqsave(&meson->lock, flags);
242
243 value = readl(meson->base + REG_MISC_AB);
244 value &= ~meson_pwm_per_channel_data[pwm->hwpwm].pwm_en_mask;
245 writel(value, meson->base + REG_MISC_AB);
246
247 spin_unlock_irqrestore(&meson->lock, flags);
248}
249
250static int meson_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
251 const struct pwm_state *state)
252{
253 struct meson_pwm *meson = to_meson_pwm(chip);
254 struct meson_pwm_channel *channel = &meson->channels[pwm->hwpwm];
255 int err = 0;
256
257 if (!state->enabled) {
258 if (state->polarity == PWM_POLARITY_INVERSED) {
259 /*
260 * This IP block revision doesn't have an "always high"
261 * setting which we can use for "inverted disabled".
262 * Instead we achieve this by setting mux parent with
263 * highest rate and minimum divider value, resulting
264 * in the shortest possible duration for one "count"
265 * and "period == duty_cycle". This results in a signal
266 * which is LOW for one "count", while being HIGH for
267 * the rest of the (so the signal is HIGH for slightly
268 * less than 100% of the period, but this is the best
269 * we can achieve).
270 */
271 channel->rate = ULONG_MAX;
272 channel->hi = ~0;
273 channel->lo = 0;
274
275 meson_pwm_enable(chip, pwm);
276 } else {
277 meson_pwm_disable(chip, pwm);
278 }
279 } else {
280 err = meson_pwm_calc(chip, pwm, state);
281 if (err < 0)
282 return err;
283
284 meson_pwm_enable(chip, pwm);
285 }
286
287 return 0;
288}
289
290static u64 meson_pwm_cnt_to_ns(struct pwm_chip *chip, struct pwm_device *pwm,
291 u32 cnt)
292{
293 struct meson_pwm *meson = to_meson_pwm(chip);
294 struct meson_pwm_channel *channel;
295 unsigned long fin_freq;
296
297 /* to_meson_pwm() can only be used after .get_state() is called */
298 channel = &meson->channels[pwm->hwpwm];
299
300 fin_freq = clk_get_rate(channel->clk);
301 if (fin_freq == 0)
302 return 0;
303
304 return div64_ul(NSEC_PER_SEC * (u64)cnt, fin_freq);
305}
306
307static int meson_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
308 struct pwm_state *state)
309{
310 struct meson_pwm *meson = to_meson_pwm(chip);
311 struct meson_pwm_channel_data *channel_data;
312 struct meson_pwm_channel *channel;
313 u32 value;
314
315 channel = &meson->channels[pwm->hwpwm];
316 channel_data = &meson_pwm_per_channel_data[pwm->hwpwm];
317
318 value = readl(meson->base + REG_MISC_AB);
319 state->enabled = value & channel_data->pwm_en_mask;
320
321 value = readl(meson->base + channel_data->reg_offset);
322 channel->lo = FIELD_GET(PWM_LOW_MASK, value);
323 channel->hi = FIELD_GET(PWM_HIGH_MASK, value);
324
325 state->period = meson_pwm_cnt_to_ns(chip, pwm, channel->lo + channel->hi);
326 state->duty_cycle = meson_pwm_cnt_to_ns(chip, pwm, channel->hi);
327
328 state->polarity = PWM_POLARITY_NORMAL;
329
330 return 0;
331}
332
333static const struct pwm_ops meson_pwm_ops = {
334 .request = meson_pwm_request,
335 .free = meson_pwm_free,
336 .apply = meson_pwm_apply,
337 .get_state = meson_pwm_get_state,
338};
339
340static int meson_pwm_init_clocks_meson8b(struct pwm_chip *chip,
341 struct clk_parent_data *mux_parent_data)
342{
343 struct meson_pwm *meson = to_meson_pwm(chip);
344 struct device *dev = pwmchip_parent(chip);
345 unsigned int i;
346 char name[255];
347 int err;
348
349 for (i = 0; i < MESON_NUM_PWMS; i++) {
350 struct meson_pwm_channel *channel = &meson->channels[i];
351 struct clk_parent_data div_parent = {}, gate_parent = {};
352 struct clk_init_data init = {};
353
354 snprintf(name, sizeof(name), "%s#mux%u", dev_name(dev), i);
355
356 init.name = name;
357 init.ops = &clk_mux_ops;
358 init.flags = 0;
359 init.parent_data = mux_parent_data;
360 init.num_parents = MESON_NUM_MUX_PARENTS;
361
362 channel->mux.reg = meson->base + REG_MISC_AB;
363 channel->mux.shift =
364 meson_pwm_per_channel_data[i].clk_sel_shift;
365 channel->mux.mask = MISC_CLK_SEL_MASK;
366 channel->mux.flags = 0;
367 channel->mux.lock = &meson->lock;
368 channel->mux.table = NULL;
369 channel->mux.hw.init = &init;
370
371 err = devm_clk_hw_register(dev, &channel->mux.hw);
372 if (err)
373 return dev_err_probe(dev, err,
374 "failed to register %s\n", name);
375
376 snprintf(name, sizeof(name), "%s#div%u", dev_name(dev), i);
377
378 init.name = name;
379 init.ops = &clk_divider_ops;
380 init.flags = CLK_SET_RATE_PARENT;
381 div_parent.index = -1;
382 div_parent.hw = &channel->mux.hw;
383 init.parent_data = &div_parent;
384 init.num_parents = 1;
385
386 channel->div.reg = meson->base + REG_MISC_AB;
387 channel->div.shift = meson_pwm_per_channel_data[i].clk_div_shift;
388 channel->div.width = MISC_CLK_DIV_WIDTH;
389 channel->div.hw.init = &init;
390 channel->div.flags = 0;
391 channel->div.lock = &meson->lock;
392
393 err = devm_clk_hw_register(dev, &channel->div.hw);
394 if (err)
395 return dev_err_probe(dev, err,
396 "failed to register %s\n", name);
397
398 snprintf(name, sizeof(name), "%s#gate%u", dev_name(dev), i);
399
400 init.name = name;
401 init.ops = &clk_gate_ops;
402 init.flags = CLK_SET_RATE_PARENT | CLK_IGNORE_UNUSED;
403 gate_parent.index = -1;
404 gate_parent.hw = &channel->div.hw;
405 init.parent_data = &gate_parent;
406 init.num_parents = 1;
407
408 channel->gate.reg = meson->base + REG_MISC_AB;
409 channel->gate.bit_idx = meson_pwm_per_channel_data[i].clk_en_shift;
410 channel->gate.hw.init = &init;
411 channel->gate.flags = 0;
412 channel->gate.lock = &meson->lock;
413
414 err = devm_clk_hw_register(dev, &channel->gate.hw);
415 if (err)
416 return dev_err_probe(dev, err, "failed to register %s\n", name);
417
418 channel->clk = devm_clk_hw_get_clk(dev, &channel->gate.hw, NULL);
419 if (IS_ERR(channel->clk))
420 return dev_err_probe(dev, PTR_ERR(channel->clk),
421 "failed to register %s\n", name);
422 }
423
424 return 0;
425}
426
427static int meson_pwm_init_channels_meson8b_legacy(struct pwm_chip *chip)
428{
429 struct clk_parent_data mux_parent_data[MESON_NUM_MUX_PARENTS] = {};
430 struct meson_pwm *meson = to_meson_pwm(chip);
431 int i;
432
433 dev_warn_once(pwmchip_parent(chip),
434 "using obsolete compatible, please consider updating dt\n");
435
436 for (i = 0; i < MESON_NUM_MUX_PARENTS; i++) {
437 mux_parent_data[i].index = -1;
438 mux_parent_data[i].name = meson->data->parent_names[i];
439 }
440
441 return meson_pwm_init_clocks_meson8b(chip, mux_parent_data);
442}
443
444static int meson_pwm_init_channels_meson8b_v2(struct pwm_chip *chip)
445{
446 struct clk_parent_data mux_parent_data[MESON_NUM_MUX_PARENTS] = {};
447 int i;
448
449 /*
450 * NOTE: Instead of relying on the hard coded names in the driver
451 * as the legacy version, this relies on DT to provide the list of
452 * clocks.
453 * For once, using input numbers actually makes more sense than names.
454 * Also DT requires clock-names to be explicitly ordered, so there is
455 * no point bothering with clock names in this case.
456 */
457 for (i = 0; i < MESON_NUM_MUX_PARENTS; i++)
458 mux_parent_data[i].index = i;
459
460 return meson_pwm_init_clocks_meson8b(chip, mux_parent_data);
461}
462
463static void meson_pwm_s4_put_clk(void *data)
464{
465 struct clk *clk = data;
466
467 clk_put(clk);
468}
469
470static int meson_pwm_init_channels_s4(struct pwm_chip *chip)
471{
472 struct device *dev = pwmchip_parent(chip);
473 struct device_node *np = dev->of_node;
474 struct meson_pwm *meson = to_meson_pwm(chip);
475 int i, ret;
476
477 for (i = 0; i < MESON_NUM_PWMS; i++) {
478 meson->channels[i].clk = of_clk_get(np, i);
479 if (IS_ERR(meson->channels[i].clk))
480 return dev_err_probe(dev,
481 PTR_ERR(meson->channels[i].clk),
482 "Failed to get clk\n");
483
484 ret = devm_add_action_or_reset(dev, meson_pwm_s4_put_clk,
485 meson->channels[i].clk);
486 if (ret)
487 return dev_err_probe(dev, ret,
488 "Failed to add clk_put action\n");
489 }
490
491 return 0;
492}
493
494static const struct meson_pwm_data pwm_meson8b_data = {
495 .parent_names = { "xtal", NULL, "fclk_div4", "fclk_div3" },
496 .channels_init = meson_pwm_init_channels_meson8b_legacy,
497};
498
499/*
500 * Only the 2 first inputs of the GXBB AO PWMs are valid
501 * The last 2 are grounded
502 */
503static const struct meson_pwm_data pwm_gxbb_ao_data = {
504 .parent_names = { "xtal", "clk81", NULL, NULL },
505 .channels_init = meson_pwm_init_channels_meson8b_legacy,
506};
507
508static const struct meson_pwm_data pwm_axg_ee_data = {
509 .parent_names = { "xtal", "fclk_div5", "fclk_div4", "fclk_div3" },
510 .channels_init = meson_pwm_init_channels_meson8b_legacy,
511};
512
513static const struct meson_pwm_data pwm_axg_ao_data = {
514 .parent_names = { "xtal", "axg_ao_clk81", "fclk_div4", "fclk_div5" },
515 .channels_init = meson_pwm_init_channels_meson8b_legacy,
516};
517
518static const struct meson_pwm_data pwm_g12a_ao_ab_data = {
519 .parent_names = { "xtal", "g12a_ao_clk81", "fclk_div4", "fclk_div5" },
520 .channels_init = meson_pwm_init_channels_meson8b_legacy,
521};
522
523static const struct meson_pwm_data pwm_g12a_ao_cd_data = {
524 .parent_names = { "xtal", "g12a_ao_clk81", NULL, NULL },
525 .channels_init = meson_pwm_init_channels_meson8b_legacy,
526};
527
528static const struct meson_pwm_data pwm_meson8_v2_data = {
529 .channels_init = meson_pwm_init_channels_meson8b_v2,
530};
531
532static const struct meson_pwm_data pwm_s4_data = {
533 .channels_init = meson_pwm_init_channels_s4,
534};
535
536static const struct of_device_id meson_pwm_matches[] = {
537 {
538 .compatible = "amlogic,meson8-pwm-v2",
539 .data = &pwm_meson8_v2_data
540 },
541 /* The following compatibles are obsolete */
542 {
543 .compatible = "amlogic,meson8b-pwm",
544 .data = &pwm_meson8b_data
545 },
546 {
547 .compatible = "amlogic,meson-gxbb-pwm",
548 .data = &pwm_meson8b_data
549 },
550 {
551 .compatible = "amlogic,meson-gxbb-ao-pwm",
552 .data = &pwm_gxbb_ao_data
553 },
554 {
555 .compatible = "amlogic,meson-axg-ee-pwm",
556 .data = &pwm_axg_ee_data
557 },
558 {
559 .compatible = "amlogic,meson-axg-ao-pwm",
560 .data = &pwm_axg_ao_data
561 },
562 {
563 .compatible = "amlogic,meson-g12a-ee-pwm",
564 .data = &pwm_meson8b_data
565 },
566 {
567 .compatible = "amlogic,meson-g12a-ao-pwm-ab",
568 .data = &pwm_g12a_ao_ab_data
569 },
570 {
571 .compatible = "amlogic,meson-g12a-ao-pwm-cd",
572 .data = &pwm_g12a_ao_cd_data
573 },
574 {
575 .compatible = "amlogic,meson-s4-pwm",
576 .data = &pwm_s4_data
577 },
578 {},
579};
580MODULE_DEVICE_TABLE(of, meson_pwm_matches);
581
582static int meson_pwm_probe(struct platform_device *pdev)
583{
584 struct pwm_chip *chip;
585 struct meson_pwm *meson;
586 int err;
587
588 chip = devm_pwmchip_alloc(&pdev->dev, MESON_NUM_PWMS, sizeof(*meson));
589 if (IS_ERR(chip))
590 return PTR_ERR(chip);
591 meson = to_meson_pwm(chip);
592
593 meson->base = devm_platform_ioremap_resource(pdev, 0);
594 if (IS_ERR(meson->base))
595 return PTR_ERR(meson->base);
596
597 spin_lock_init(&meson->lock);
598 chip->ops = &meson_pwm_ops;
599
600 meson->data = of_device_get_match_data(&pdev->dev);
601
602 err = meson->data->channels_init(chip);
603 if (err < 0)
604 return err;
605
606 err = devm_pwmchip_add(&pdev->dev, chip);
607 if (err < 0)
608 return dev_err_probe(&pdev->dev, err,
609 "failed to register PWM chip\n");
610
611 return 0;
612}
613
614static struct platform_driver meson_pwm_driver = {
615 .driver = {
616 .name = "meson-pwm",
617 .of_match_table = meson_pwm_matches,
618 },
619 .probe = meson_pwm_probe,
620};
621module_platform_driver(meson_pwm_driver);
622
623MODULE_DESCRIPTION("Amlogic Meson PWM Generator driver");
624MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
625MODULE_LICENSE("Dual BSD/GPL");