aboutsummaryrefslogtreecommitdiff
path: root/drivers/pwm/pwm-meson.c
blob: 6245bbdb6e6c1fab35dcff18c605bb5f24f38848 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/*
 * PWM controller driver for Amlogic Meson SoCs.
 *
 * This PWM is only a set of Gates, Dividers and Counters:
 * PWM output is achieved by calculating a clock that permits calculating
 * two periods (low and high). The counter then has to be set to switch after
 * N cycles for the first half period.
 * The hardware has no "polarity" setting. This driver reverses the period
 * cycles (the low length is inverted with the high length) for
 * PWM_POLARITY_INVERSED. This means that .get_state cannot read the polarity
 * from the hardware.
 * Setting the duty cycle will disable and re-enable the PWM output.
 * Disabling the PWM stops the output immediately (without waiting for the
 * current period to complete first).
 *
 * The public S912 (GXM) datasheet contains some documentation for this PWM
 * controller starting on page 543:
 * https://dl.khadas.com/Hardware/VIM2/Datasheet/S912_Datasheet_V0.220170314publicversion-Wesion.pdf
 * An updated version of this IP block is found in S922X (G12B) SoCs. The
 * datasheet contains the description for this IP block revision starting at
 * page 1084:
 * https://dn.odroid.com/S922X/ODROID-N2/Datasheet/S922X_Public_Datasheet_V0.2.pdf
 *
 * Copyright (c) 2016 BayLibre, SAS.
 * Author: Neil Armstrong <narmstrong@baylibre.com>
 * Copyright (C) 2014 Amlogic, Inc.
 */

#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/math64.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

#define REG_PWM_A		0x0
#define REG_PWM_B		0x4
#define PWM_LOW_MASK		GENMASK(15, 0)
#define PWM_HIGH_MASK		GENMASK(31, 16)

#define REG_MISC_AB		0x8
#define MISC_B_CLK_EN		BIT(23)
#define MISC_A_CLK_EN		BIT(15)
#define MISC_CLK_DIV_MASK	0x7f
#define MISC_B_CLK_DIV_SHIFT	16
#define MISC_A_CLK_DIV_SHIFT	8
#define MISC_B_CLK_SEL_SHIFT	6
#define MISC_A_CLK_SEL_SHIFT	4
#define MISC_CLK_SEL_MASK	0x3
#define MISC_B_EN		BIT(1)
#define MISC_A_EN		BIT(0)

#define MESON_NUM_PWMS		2

static struct meson_pwm_channel_data {
	u8		reg_offset;
	u8		clk_sel_shift;
	u8		clk_div_shift;
	u32		clk_en_mask;
	u32		pwm_en_mask;
} meson_pwm_per_channel_data[MESON_NUM_PWMS] = {
	{
		.reg_offset	= REG_PWM_A,
		.clk_sel_shift	= MISC_A_CLK_SEL_SHIFT,
		.clk_div_shift	= MISC_A_CLK_DIV_SHIFT,
		.clk_en_mask	= MISC_A_CLK_EN,
		.pwm_en_mask	= MISC_A_EN,
	},
	{
		.reg_offset	= REG_PWM_B,
		.clk_sel_shift	= MISC_B_CLK_SEL_SHIFT,
		.clk_div_shift	= MISC_B_CLK_DIV_SHIFT,
		.clk_en_mask	= MISC_B_CLK_EN,
		.pwm_en_mask	= MISC_B_EN,
	}
};

struct meson_pwm_channel {
	unsigned int hi;
	unsigned int lo;
	u8 pre_div;

	struct clk *clk_parent;
	struct clk_mux mux;
	struct clk *clk;
};

struct meson_pwm_data {
	const char * const *parent_names;
	unsigned int num_parents;
};

struct meson_pwm {
	struct pwm_chip chip;
	const struct meson_pwm_data *data;
	struct meson_pwm_channel channels[MESON_NUM_PWMS];
	void __iomem *base;
	/*
	 * Protects register (write) access to the REG_MISC_AB register
	 * that is shared between the two PWMs.
	 */
	spinlock_t lock;
};

static inline struct meson_pwm *to_meson_pwm(struct pwm_chip *chip)
{
	return container_of(chip, struct meson_pwm, chip);
}

static int meson_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct meson_pwm *meson = to_meson_pwm(chip);
	struct meson_pwm_channel *channel;
	struct device *dev = chip->dev;
	int err;

	channel = pwm_get_chip_data(pwm);
	if (channel)
		return 0;

	channel = &meson->channels[pwm->hwpwm];

	if (channel->clk_parent) {
		err = clk_set_parent(channel->clk, channel->clk_parent);
		if (err < 0) {
			dev_err(dev, "failed to set parent %s for %s: %d\n",
				__clk_get_name(channel->clk_parent),
				__clk_get_name(channel->clk), err);
				return err;
		}
	}

	err = clk_prepare_enable(channel->clk);
	if (err < 0) {
		dev_err(dev, "failed to enable clock %s: %d\n",
			__clk_get_name(channel->clk), err);
		return err;
	}

	return pwm_set_chip_data(pwm, channel);
}

static void meson_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);

	if (channel)
		clk_disable_unprepare(channel->clk);
}

static int meson_pwm_calc(struct meson_pwm *meson, struct pwm_device *pwm,
			  const struct pwm_state *state)
{
	struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
	unsigned int duty, period, pre_div, cnt, duty_cnt;
	unsigned long fin_freq = -1;

	duty = state->duty_cycle;
	period = state->period;

	if (state->polarity == PWM_POLARITY_INVERSED)
		duty = period - duty;

	fin_freq = clk_get_rate(channel->clk);
	if (fin_freq == 0) {
		dev_err(meson->chip.dev, "invalid source clock frequency\n");
		return -EINVAL;
	}

	dev_dbg(meson->chip.dev, "fin_freq: %lu Hz\n", fin_freq);

	pre_div = div64_u64(fin_freq * (u64)period, NSEC_PER_SEC * 0xffffLL);
	if (pre_div > MISC_CLK_DIV_MASK) {
		dev_err(meson->chip.dev, "unable to get period pre_div\n");
		return -EINVAL;
	}

	cnt = div64_u64(fin_freq * (u64)period, NSEC_PER_SEC * (pre_div + 1));
	if (cnt > 0xffff) {
		dev_err(meson->chip.dev, "unable to get period cnt\n");
		return -EINVAL;
	}

	dev_dbg(meson->chip.dev, "period=%u pre_div=%u cnt=%u\n", period,
		pre_div, cnt);

	if (duty == period) {
		channel->pre_div = pre_div;
		channel->hi = cnt;
		channel->lo = 0;
	} else if (duty == 0) {
		channel->pre_div = pre_div;
		channel->hi = 0;
		channel->lo = cnt;
	} else {
		/* Then check is we can have the duty with the same pre_div */
		duty_cnt = div64_u64(fin_freq * (u64)duty,
				     NSEC_PER_SEC * (pre_div + 1));
		if (duty_cnt > 0xffff) {
			dev_err(meson->chip.dev, "unable to get duty cycle\n");
			return -EINVAL;
		}

		dev_dbg(meson->chip.dev, "duty=%u pre_div=%u duty_cnt=%u\n",
			duty, pre_div, duty_cnt);

		channel->pre_div = pre_div;
		channel->hi = duty_cnt;
		channel->lo = cnt - duty_cnt;
	}

	return 0;
}

static void meson_pwm_enable(struct meson_pwm *meson, struct pwm_device *pwm)
{
	struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
	struct meson_pwm_channel_data *channel_data;
	unsigned long flags;
	u32 value;

	channel_data = &meson_pwm_per_channel_data[pwm->hwpwm];

	spin_lock_irqsave(&meson->lock, flags);

	value = readl(meson->base + REG_MISC_AB);
	value &= ~(MISC_CLK_DIV_MASK << channel_data->clk_div_shift);
	value |= channel->pre_div << channel_data->clk_div_shift;
	value |= channel_data->clk_en_mask;
	writel(value, meson->base + REG_MISC_AB);

	value = FIELD_PREP(PWM_HIGH_MASK, channel->hi) |
		FIELD_PREP(PWM_LOW_MASK, channel->lo);
	writel(value, meson->base + channel_data->reg_offset);

	value = readl(meson->base + REG_MISC_AB);
	value |= channel_data->pwm_en_mask;
	writel(value, meson->base + REG_MISC_AB);

	spin_unlock_irqrestore(&meson->lock, flags);
}

static void meson_pwm_disable(struct meson_pwm *meson, struct pwm_device *pwm)
{
	unsigned long flags;
	u32 value;

	spin_lock_irqsave(&meson->lock, flags);

	value = readl(meson->base + REG_MISC_AB);
	value &= ~meson_pwm_per_channel_data[pwm->hwpwm].pwm_en_mask;
	writel(value, meson->base + REG_MISC_AB);

	spin_unlock_irqrestore(&meson->lock, flags);
}

static int meson_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
			   const struct pwm_state *state)
{
	struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
	struct meson_pwm *meson = to_meson_pwm(chip);
	int err = 0;

	if (!state)
		return -EINVAL;

	if (!state->enabled) {
		if (state->polarity == PWM_POLARITY_INVERSED) {
			/*
			 * This IP block revision doesn't have an "always high"
			 * setting which we can use for "inverted disabled".
			 * Instead we achieve this using the same settings
			 * that we use a pre_div of 0 (to get the shortest
			 * possible duration for one "count") and
			 * "period == duty_cycle". This results in a signal
			 * which is LOW for one "count", while being HIGH for
			 * the rest of the (so the signal is HIGH for slightly
			 * less than 100% of the period, but this is the best
			 * we can achieve).
			 */
			channel->pre_div = 0;
			channel->hi = ~0;
			channel->lo = 0;

			meson_pwm_enable(meson, pwm);
		} else {
			meson_pwm_disable(meson, pwm);
		}
	} else {
		err = meson_pwm_calc(meson, pwm, state);
		if (err < 0)
			return err;

		meson_pwm_enable(meson, pwm);
	}

	return 0;
}

static unsigned int meson_pwm_cnt_to_ns(struct pwm_chip *chip,
					struct pwm_device *pwm, u32 cnt)
{
	struct meson_pwm *meson = to_meson_pwm(chip);
	struct meson_pwm_channel *channel;
	unsigned long fin_freq;
	u32 fin_ns;

	/* to_meson_pwm() can only be used after .get_state() is called */
	channel = &meson->channels[pwm->hwpwm];

	fin_freq = clk_get_rate(channel->clk);
	if (fin_freq == 0)
		return 0;

	fin_ns = div_u64(NSEC_PER_SEC, fin_freq);

	return cnt * fin_ns * (channel->pre_div + 1);
}

static void meson_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
				struct pwm_state *state)
{
	struct meson_pwm *meson = to_meson_pwm(chip);
	struct meson_pwm_channel_data *channel_data;
	struct meson_pwm_channel *channel;
	u32 value, tmp;

	if (!state)
		return;

	channel = &meson->channels[pwm->hwpwm];
	channel_data = &meson_pwm_per_channel_data[pwm->hwpwm];

	value = readl(meson->base + REG_MISC_AB);

	tmp = channel_data->pwm_en_mask | channel_data->clk_en_mask;
	state->enabled = (value & tmp) == tmp;

	tmp = value >> channel_data->clk_div_shift;
	channel->pre_div = FIELD_GET(MISC_CLK_DIV_MASK, tmp);

	value = readl(meson->base + channel_data->reg_offset);

	channel->lo = FIELD_GET(PWM_LOW_MASK, value);
	channel->hi = FIELD_GET(PWM_HIGH_MASK, value);

	if (channel->lo == 0) {
		state->period = meson_pwm_cnt_to_ns(chip, pwm, channel->hi);
		state->duty_cycle = state->period;
	} else if (channel->lo >= channel->hi) {
		state->period = meson_pwm_cnt_to_ns(chip, pwm,
						    channel->lo + channel->hi);
		state->duty_cycle = meson_pwm_cnt_to_ns(chip, pwm,
							channel->hi);
	} else {
		state->period = 0;
		state->duty_cycle = 0;
	}
}

static const struct pwm_ops meson_pwm_ops = {
	.request = meson_pwm_request,
	.free = meson_pwm_free,
	.apply = meson_pwm_apply,
	.get_state = meson_pwm_get_state,
	.owner = THIS_MODULE,
};

static const char * const pwm_meson8b_parent_names[] = {
	"xtal", "vid_pll", "fclk_div4", "fclk_div3"
};

static const struct meson_pwm_data pwm_meson8b_data = {
	.parent_names = pwm_meson8b_parent_names,
	.num_parents = ARRAY_SIZE(pwm_meson8b_parent_names),
};

static const char * const pwm_gxbb_parent_names[] = {
	"xtal", "hdmi_pll", "fclk_div4", "fclk_div3"
};

static const struct meson_pwm_data pwm_gxbb_data = {
	.parent_names = pwm_gxbb_parent_names,
	.num_parents = ARRAY_SIZE(pwm_gxbb_parent_names),
};

/*
 * Only the 2 first inputs of the GXBB AO PWMs are valid
 * The last 2 are grounded
 */
static const char * const pwm_gxbb_ao_parent_names[] = {
	"xtal", "clk81"
};

static const struct meson_pwm_data pwm_gxbb_ao_data = {
	.parent_names = pwm_gxbb_ao_parent_names,
	.num_parents = ARRAY_SIZE(pwm_gxbb_ao_parent_names),
};

static const char * const pwm_axg_ee_parent_names[] = {
	"xtal", "fclk_div5", "fclk_div4", "fclk_div3"
};

static const struct meson_pwm_data pwm_axg_ee_data = {
	.parent_names = pwm_axg_ee_parent_names,
	.num_parents = ARRAY_SIZE(pwm_axg_ee_parent_names),
};

static const char * const pwm_axg_ao_parent_names[] = {
	"aoclk81", "xtal", "fclk_div4", "fclk_div5"
};

static const struct meson_pwm_data pwm_axg_ao_data = {
	.parent_names = pwm_axg_ao_parent_names,
	.num_parents = ARRAY_SIZE(pwm_axg_ao_parent_names),
};

static const char * const pwm_g12a_ao_ab_parent_names[] = {
	"xtal", "aoclk81", "fclk_div4", "fclk_div5"
};

static const struct meson_pwm_data pwm_g12a_ao_ab_data = {
	.parent_names = pwm_g12a_ao_ab_parent_names,
	.num_parents = ARRAY_SIZE(pwm_g12a_ao_ab_parent_names),
};

static const char * const pwm_g12a_ao_cd_parent_names[] = {
	"xtal", "aoclk81",
};

static const struct meson_pwm_data pwm_g12a_ao_cd_data = {
	.parent_names = pwm_g12a_ao_cd_parent_names,
	.num_parents = ARRAY_SIZE(pwm_g12a_ao_cd_parent_names),
};

static const char * const pwm_g12a_ee_parent_names[] = {
	"xtal", "hdmi_pll", "fclk_div4", "fclk_div3"
};

static const struct meson_pwm_data pwm_g12a_ee_data = {
	.parent_names = pwm_g12a_ee_parent_names,
	.num_parents = ARRAY_SIZE(pwm_g12a_ee_parent_names),
};

static const struct of_device_id meson_pwm_matches[] = {
	{
		.compatible = "amlogic,meson8b-pwm",
		.data = &pwm_meson8b_data
	},
	{
		.compatible = "amlogic,meson-gxbb-pwm",
		.data = &pwm_gxbb_data
	},
	{
		.compatible = "amlogic,meson-gxbb-ao-pwm",
		.data = &pwm_gxbb_ao_data
	},
	{
		.compatible = "amlogic,meson-axg-ee-pwm",
		.data = &pwm_axg_ee_data
	},
	{
		.compatible = "amlogic,meson-axg-ao-pwm",
		.data = &pwm_axg_ao_data
	},
	{
		.compatible = "amlogic,meson-g12a-ee-pwm",
		.data = &pwm_g12a_ee_data
	},
	{
		.compatible = "amlogic,meson-g12a-ao-pwm-ab",
		.data = &pwm_g12a_ao_ab_data
	},
	{
		.compatible = "amlogic,meson-g12a-ao-pwm-cd",
		.data = &pwm_g12a_ao_cd_data
	},
	{},
};
MODULE_DEVICE_TABLE(of, meson_pwm_matches);

static int meson_pwm_init_channels(struct meson_pwm *meson)
{
	struct device *dev = meson->chip.dev;
	struct clk_init_data init;
	unsigned int i;
	char name[255];
	int err;

	for (i = 0; i < meson->chip.npwm; i++) {
		struct meson_pwm_channel *channel = &meson->channels[i];

		snprintf(name, sizeof(name), "%s#mux%u", dev_name(dev), i);

		init.name = name;
		init.ops = &clk_mux_ops;
		init.flags = 0;
		init.parent_names = meson->data->parent_names;
		init.num_parents = meson->data->num_parents;

		channel->mux.reg = meson->base + REG_MISC_AB;
		channel->mux.shift =
				meson_pwm_per_channel_data[i].clk_sel_shift;
		channel->mux.mask = MISC_CLK_SEL_MASK;
		channel->mux.flags = 0;
		channel->mux.lock = &meson->lock;
		channel->mux.table = NULL;
		channel->mux.hw.init = &init;

		channel->clk = devm_clk_register(dev, &channel->mux.hw);
		if (IS_ERR(channel->clk)) {
			err = PTR_ERR(channel->clk);
			dev_err(dev, "failed to register %s: %d\n", name, err);
			return err;
		}

		snprintf(name, sizeof(name), "clkin%u", i);

		channel->clk_parent = devm_clk_get_optional(dev, name);
		if (IS_ERR(channel->clk_parent))
			return PTR_ERR(channel->clk_parent);
	}

	return 0;
}

static int meson_pwm_probe(struct platform_device *pdev)
{
	struct meson_pwm *meson;
	struct resource *regs;
	int err;

	meson = devm_kzalloc(&pdev->dev, sizeof(*meson), GFP_KERNEL);
	if (!meson)
		return -ENOMEM;

	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	meson->base = devm_ioremap_resource(&pdev->dev, regs);
	if (IS_ERR(meson->base))
		return PTR_ERR(meson->base);

	spin_lock_init(&meson->lock);
	meson->chip.dev = &pdev->dev;
	meson->chip.ops = &meson_pwm_ops;
	meson->chip.base = -1;
	meson->chip.npwm = MESON_NUM_PWMS;
	meson->chip.of_xlate = of_pwm_xlate_with_flags;
	meson->chip.of_pwm_n_cells = 3;

	meson->data = of_device_get_match_data(&pdev->dev);

	err = meson_pwm_init_channels(meson);
	if (err < 0)
		return err;

	err = pwmchip_add(&meson->chip);
	if (err < 0) {
		dev_err(&pdev->dev, "failed to register PWM chip: %d\n", err);
		return err;
	}

	platform_set_drvdata(pdev, meson);

	return 0;
}

static int meson_pwm_remove(struct platform_device *pdev)
{
	struct meson_pwm *meson = platform_get_drvdata(pdev);

	return pwmchip_remove(&meson->chip);
}

static struct platform_driver meson_pwm_driver = {
	.driver = {
		.name = "meson-pwm",
		.of_match_table = meson_pwm_matches,
	},
	.probe = meson_pwm_probe,
	.remove = meson_pwm_remove,
};
module_platform_driver(meson_pwm_driver);

MODULE_DESCRIPTION("Amlogic Meson PWM Generator driver");
MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
MODULE_LICENSE("Dual BSD/GPL");