summaryrefslogtreecommitdiffstats
path: root/drivers/pwm/pwm-atmel-hlcdc.c
blob: 584288d8c0503117501ee889baa19b124889aa24 (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2014 Free Electrons
 * Copyright (C) 2014 Atmel
 *
 * Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/mfd/atmel-hlcdc.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/regmap.h>

#define ATMEL_HLCDC_PWMCVAL_MASK	GENMASK(15, 8)
#define ATMEL_HLCDC_PWMCVAL(x)		(((x) << 8) & ATMEL_HLCDC_PWMCVAL_MASK)
#define ATMEL_HLCDC_PWMPOL		BIT(4)
#define ATMEL_HLCDC_PWMPS_MASK		GENMASK(2, 0)
#define ATMEL_HLCDC_PWMPS_MAX		0x6
#define ATMEL_HLCDC_PWMPS(x)		((x) & ATMEL_HLCDC_PWMPS_MASK)

struct atmel_hlcdc_pwm_errata {
	bool slow_clk_erratum;
	bool div1_clk_erratum;
};

struct atmel_hlcdc_pwm {
	struct pwm_chip chip;
	struct atmel_hlcdc *hlcdc;
	struct clk *cur_clk;
	const struct atmel_hlcdc_pwm_errata *errata;
};

static inline struct atmel_hlcdc_pwm *to_atmel_hlcdc_pwm(struct pwm_chip *chip)
{
	return container_of(chip, struct atmel_hlcdc_pwm, chip);
}

static int atmel_hlcdc_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
				 const struct pwm_state *state)
{
	struct atmel_hlcdc_pwm *atmel = to_atmel_hlcdc_pwm(chip);
	struct atmel_hlcdc *hlcdc = atmel->hlcdc;
	unsigned int status;
	int ret;

	if (state->enabled) {
		struct clk *new_clk = hlcdc->slow_clk;
		u64 pwmcval = state->duty_cycle * 256;
		unsigned long clk_freq;
		u64 clk_period_ns;
		u32 pwmcfg;
		int pres;

		if (!atmel->errata || !atmel->errata->slow_clk_erratum) {
			clk_freq = clk_get_rate(new_clk);
			if (!clk_freq)
				return -EINVAL;

			clk_period_ns = (u64)NSEC_PER_SEC * 256;
			do_div(clk_period_ns, clk_freq);
		}

		/* Errata: cannot use slow clk on some IP revisions */
		if ((atmel->errata && atmel->errata->slow_clk_erratum) ||
		    clk_period_ns > state->period) {
			new_clk = hlcdc->sys_clk;
			clk_freq = clk_get_rate(new_clk);
			if (!clk_freq)
				return -EINVAL;

			clk_period_ns = (u64)NSEC_PER_SEC * 256;
			do_div(clk_period_ns, clk_freq);
		}

		for (pres = 0; pres <= ATMEL_HLCDC_PWMPS_MAX; pres++) {
		/* Errata: cannot divide by 1 on some IP revisions */
			if (!pres && atmel->errata &&
			    atmel->errata->div1_clk_erratum)
				continue;

			if ((clk_period_ns << pres) >= state->period)
				break;
		}

		if (pres > ATMEL_HLCDC_PWMPS_MAX)
			return -EINVAL;

		pwmcfg = ATMEL_HLCDC_PWMPS(pres);

		if (new_clk != atmel->cur_clk) {
			u32 gencfg = 0;
			int ret;

			ret = clk_prepare_enable(new_clk);
			if (ret)
				return ret;

			clk_disable_unprepare(atmel->cur_clk);
			atmel->cur_clk = new_clk;

			if (new_clk == hlcdc->sys_clk)
				gencfg = ATMEL_HLCDC_CLKPWMSEL;

			ret = regmap_update_bits(hlcdc->regmap,
						 ATMEL_HLCDC_CFG(0),
						 ATMEL_HLCDC_CLKPWMSEL,
						 gencfg);
			if (ret)
				return ret;
		}

		do_div(pwmcval, state->period);

		/*
		 * The PWM duty cycle is configurable from 0/256 to 255/256 of
		 * the period cycle. Hence we can't set a duty cycle occupying
		 * the whole period cycle if we're asked to.
		 * Set it to 255 if pwmcval is greater than 256.
		 */
		if (pwmcval > 255)
			pwmcval = 255;

		pwmcfg |= ATMEL_HLCDC_PWMCVAL(pwmcval);

		if (state->polarity == PWM_POLARITY_NORMAL)
			pwmcfg |= ATMEL_HLCDC_PWMPOL;

		ret = regmap_update_bits(hlcdc->regmap, ATMEL_HLCDC_CFG(6),
					 ATMEL_HLCDC_PWMCVAL_MASK |
					 ATMEL_HLCDC_PWMPS_MASK |
					 ATMEL_HLCDC_PWMPOL,
					 pwmcfg);
		if (ret)
			return ret;

		ret = regmap_write(hlcdc->regmap, ATMEL_HLCDC_EN,
				   ATMEL_HLCDC_PWM);
		if (ret)
			return ret;

		ret = regmap_read_poll_timeout(hlcdc->regmap, ATMEL_HLCDC_SR,
					       status,
					       status & ATMEL_HLCDC_PWM,
					       10, 0);
		if (ret)
			return ret;
	} else {
		ret = regmap_write(hlcdc->regmap, ATMEL_HLCDC_DIS,
				   ATMEL_HLCDC_PWM);
		if (ret)
			return ret;

		ret = regmap_read_poll_timeout(hlcdc->regmap, ATMEL_HLCDC_SR,
					       status,
					       !(status & ATMEL_HLCDC_PWM),
					       10, 0);
		if (ret)
			return ret;

		clk_disable_unprepare(atmel->cur_clk);
		atmel->cur_clk = NULL;
	}

	return 0;
}

static const struct pwm_ops atmel_hlcdc_pwm_ops = {
	.apply = atmel_hlcdc_pwm_apply,
};

static const struct atmel_hlcdc_pwm_errata atmel_hlcdc_pwm_at91sam9x5_errata = {
	.slow_clk_erratum = true,
};

static const struct atmel_hlcdc_pwm_errata atmel_hlcdc_pwm_sama5d3_errata = {
	.div1_clk_erratum = true,
};

#ifdef CONFIG_PM_SLEEP
static int atmel_hlcdc_pwm_suspend(struct device *dev)
{
	struct atmel_hlcdc_pwm *atmel = dev_get_drvdata(dev);

	/* Keep the periph clock enabled if the PWM is still running. */
	if (!pwm_is_enabled(&atmel->chip.pwms[0]))
		clk_disable_unprepare(atmel->hlcdc->periph_clk);

	return 0;
}

static int atmel_hlcdc_pwm_resume(struct device *dev)
{
	struct atmel_hlcdc_pwm *atmel = dev_get_drvdata(dev);
	struct pwm_state state;
	int ret;

	pwm_get_state(&atmel->chip.pwms[0], &state);

	/* Re-enable the periph clock it was stopped during suspend. */
	if (!state.enabled) {
		ret = clk_prepare_enable(atmel->hlcdc->periph_clk);
		if (ret)
			return ret;
	}

	return atmel_hlcdc_pwm_apply(&atmel->chip, &atmel->chip.pwms[0],
				     &state);
}
#endif

static SIMPLE_DEV_PM_OPS(atmel_hlcdc_pwm_pm_ops,
			 atmel_hlcdc_pwm_suspend, atmel_hlcdc_pwm_resume);

static const struct of_device_id atmel_hlcdc_dt_ids[] = {
	{
		.compatible = "atmel,at91sam9n12-hlcdc",
		/* 9n12 has same errata as 9x5 HLCDC PWM */
		.data = &atmel_hlcdc_pwm_at91sam9x5_errata,
	},
	{
		.compatible = "atmel,at91sam9x5-hlcdc",
		.data = &atmel_hlcdc_pwm_at91sam9x5_errata,
	},
	{
		.compatible = "atmel,sama5d2-hlcdc",
	},
	{
		.compatible = "atmel,sama5d3-hlcdc",
		.data = &atmel_hlcdc_pwm_sama5d3_errata,
	},
	{
		.compatible = "atmel,sama5d4-hlcdc",
		.data = &atmel_hlcdc_pwm_sama5d3_errata,
	},
	{	.compatible = "microchip,sam9x60-hlcdc", },
	{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, atmel_hlcdc_dt_ids);

static int atmel_hlcdc_pwm_probe(struct platform_device *pdev)
{
	const struct of_device_id *match;
	struct device *dev = &pdev->dev;
	struct atmel_hlcdc_pwm *atmel;
	struct atmel_hlcdc *hlcdc;
	int ret;

	hlcdc = dev_get_drvdata(dev->parent);

	atmel = devm_kzalloc(dev, sizeof(*atmel), GFP_KERNEL);
	if (!atmel)
		return -ENOMEM;

	ret = clk_prepare_enable(hlcdc->periph_clk);
	if (ret)
		return ret;

	match = of_match_node(atmel_hlcdc_dt_ids, dev->parent->of_node);
	if (match)
		atmel->errata = match->data;

	atmel->hlcdc = hlcdc;
	atmel->chip.ops = &atmel_hlcdc_pwm_ops;
	atmel->chip.dev = dev;
	atmel->chip.npwm = 1;

	ret = pwmchip_add(&atmel->chip);
	if (ret) {
		clk_disable_unprepare(hlcdc->periph_clk);
		return ret;
	}

	platform_set_drvdata(pdev, atmel);

	return 0;
}

static void atmel_hlcdc_pwm_remove(struct platform_device *pdev)
{
	struct atmel_hlcdc_pwm *atmel = platform_get_drvdata(pdev);

	pwmchip_remove(&atmel->chip);

	clk_disable_unprepare(atmel->hlcdc->periph_clk);
}

static const struct of_device_id atmel_hlcdc_pwm_dt_ids[] = {
	{ .compatible = "atmel,hlcdc-pwm" },
	{ /* sentinel */ },
};

static struct platform_driver atmel_hlcdc_pwm_driver = {
	.driver = {
		.name = "atmel-hlcdc-pwm",
		.of_match_table = atmel_hlcdc_pwm_dt_ids,
		.pm = &atmel_hlcdc_pwm_pm_ops,
	},
	.probe = atmel_hlcdc_pwm_probe,
	.remove_new = atmel_hlcdc_pwm_remove,
};
module_platform_driver(atmel_hlcdc_pwm_driver);

MODULE_ALIAS("platform:atmel-hlcdc-pwm");
MODULE_AUTHOR("Boris Brezillon <boris.brezillon@free-electrons.com>");
MODULE_DESCRIPTION("Atmel HLCDC PWM driver");
MODULE_LICENSE("GPL v2");