Home Home > GIT Browse
summaryrefslogtreecommitdiff
blob: 7c8d6a168ceb254c69420ab293f08e3b43fcdd18 (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
/*
 * Marvell Berlin PWM driver
 *
 * Copyright (C) 2015 Marvell Technology Group Ltd.
 *
 * Author: Antoine Tenart <antoine.tenart@free-electrons.com>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/clk.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/slab.h>

#define BERLIN_PWM_EN			0x0
#define  BERLIN_PWM_ENABLE		BIT(0)
#define BERLIN_PWM_CONTROL		0x4
/*
 * The prescaler claims to support 8 different moduli, configured using the
 * low three bits of PWM_CONTROL. (Sequentially, they are 1, 4, 8, 16, 64,
 * 256, 1024, and 4096.)  However, the moduli from 4 to 1024 appear to be
 * implemented by internally shifting TCNT left without adding additional
 * bits. So, the max TCNT that actually works for a modulus of 4 is 0x3fff;
 * for 8, 0x1fff; and so on. This means that those moduli are entirely
 * useless, as we could just do the shift ourselves. The 4096 modulus is
 * implemented with a real prescaler, so we do use that, but we treat it
 * as a flag instead of pretending the modulus is actually configurable.
 */
#define  BERLIN_PWM_PRESCALE_4096	0x7
#define  BERLIN_PWM_INVERT_POLARITY	BIT(3)
#define BERLIN_PWM_DUTY			0x8
#define BERLIN_PWM_TCNT			0xc
#define  BERLIN_PWM_MAX_TCNT		65535

struct berlin_pwm_channel {
	u32 enable;
	u32 ctrl;
	u32 duty;
	u32 tcnt;
};

struct berlin_pwm_chip {
	struct pwm_chip chip;
	struct clk *clk;
	void __iomem *base;
};

static inline struct berlin_pwm_chip *to_berlin_pwm_chip(struct pwm_chip *chip)
{
	return container_of(chip, struct berlin_pwm_chip, chip);
}

static inline u32 berlin_pwm_readl(struct berlin_pwm_chip *chip,
				   unsigned int channel, unsigned long offset)
{
	return readl_relaxed(chip->base + channel * 0x10 + offset);
}

static inline void berlin_pwm_writel(struct berlin_pwm_chip *chip,
				     unsigned int channel, u32 value,
				     unsigned long offset)
{
	writel_relaxed(value, chip->base + channel * 0x10 + offset);
}

static int berlin_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct berlin_pwm_channel *channel;

	channel = kzalloc(sizeof(*channel), GFP_KERNEL);
	if (!channel)
		return -ENOMEM;

	return pwm_set_chip_data(pwm, channel);
}

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

	pwm_set_chip_data(pwm, NULL);
	kfree(channel);
}

static int berlin_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm_dev,
			     int duty_ns, int period_ns)
{
	struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
	bool prescale_4096 = false;
	u32 value, duty, period;
	u64 cycles;

	cycles = clk_get_rate(pwm->clk);
	cycles *= period_ns;
	do_div(cycles, NSEC_PER_SEC);

	if (cycles > BERLIN_PWM_MAX_TCNT) {
		prescale_4096 = true;
		cycles >>= 12; // Prescaled by 4096

		if (cycles > BERLIN_PWM_MAX_TCNT)
			return -ERANGE;
	}

	period = cycles;
	cycles *= duty_ns;
	do_div(cycles, period_ns);
	duty = cycles;

	value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_CONTROL);
	if (prescale_4096)
		value |= BERLIN_PWM_PRESCALE_4096;
	else
		value &= ~BERLIN_PWM_PRESCALE_4096;
	berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_CONTROL);

	berlin_pwm_writel(pwm, pwm_dev->hwpwm, duty, BERLIN_PWM_DUTY);
	berlin_pwm_writel(pwm, pwm_dev->hwpwm, period, BERLIN_PWM_TCNT);

	return 0;
}

static int berlin_pwm_set_polarity(struct pwm_chip *chip,
				   struct pwm_device *pwm_dev,
				   enum pwm_polarity polarity)
{
	struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
	u32 value;

	value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_CONTROL);

	if (polarity == PWM_POLARITY_NORMAL)
		value &= ~BERLIN_PWM_INVERT_POLARITY;
	else
		value |= BERLIN_PWM_INVERT_POLARITY;

	berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_CONTROL);

	return 0;
}

static int berlin_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm_dev)
{
	struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
	u32 value;

	value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_EN);
	value |= BERLIN_PWM_ENABLE;
	berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_EN);

	return 0;
}

static void berlin_pwm_disable(struct pwm_chip *chip,
			       struct pwm_device *pwm_dev)
{
	struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
	u32 value;

	value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_EN);
	value &= ~BERLIN_PWM_ENABLE;
	berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_EN);
}

static const struct pwm_ops berlin_pwm_ops = {
	.request = berlin_pwm_request,
	.free = berlin_pwm_free,
	.config = berlin_pwm_config,
	.set_polarity = berlin_pwm_set_polarity,
	.enable = berlin_pwm_enable,
	.disable = berlin_pwm_disable,
	.owner = THIS_MODULE,
};

static const struct of_device_id berlin_pwm_match[] = {
	{ .compatible = "marvell,berlin-pwm" },
	{ },
};
MODULE_DEVICE_TABLE(of, berlin_pwm_match);

static int berlin_pwm_probe(struct platform_device *pdev)
{
	struct berlin_pwm_chip *pwm;
	struct resource *res;
	int ret;

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

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

	pwm->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(pwm->clk))
		return PTR_ERR(pwm->clk);

	ret = clk_prepare_enable(pwm->clk);
	if (ret)
		return ret;

	pwm->chip.dev = &pdev->dev;
	pwm->chip.ops = &berlin_pwm_ops;
	pwm->chip.base = -1;
	pwm->chip.npwm = 4;
	pwm->chip.of_xlate = of_pwm_xlate_with_flags;
	pwm->chip.of_pwm_n_cells = 3;

	ret = pwmchip_add(&pwm->chip);
	if (ret < 0) {
		dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
		clk_disable_unprepare(pwm->clk);
		return ret;
	}

	platform_set_drvdata(pdev, pwm);

	return 0;
}

static int berlin_pwm_remove(struct platform_device *pdev)
{
	struct berlin_pwm_chip *pwm = platform_get_drvdata(pdev);
	int ret;

	ret = pwmchip_remove(&pwm->chip);
	clk_disable_unprepare(pwm->clk);

	return ret;
}

#ifdef CONFIG_PM_SLEEP
static int berlin_pwm_suspend(struct device *dev)
{
	struct berlin_pwm_chip *pwm = dev_get_drvdata(dev);
	unsigned int i;

	for (i = 0; i < pwm->chip.npwm; i++) {
		struct berlin_pwm_channel *channel;

		channel = pwm_get_chip_data(&pwm->chip.pwms[i]);
		if (!channel)
			continue;

		channel->enable = berlin_pwm_readl(pwm, i, BERLIN_PWM_ENABLE);
		channel->ctrl = berlin_pwm_readl(pwm, i, BERLIN_PWM_CONTROL);
		channel->duty = berlin_pwm_readl(pwm, i, BERLIN_PWM_DUTY);
		channel->tcnt = berlin_pwm_readl(pwm, i, BERLIN_PWM_TCNT);
	}

	clk_disable_unprepare(pwm->clk);

	return 0;
}

static int berlin_pwm_resume(struct device *dev)
{
	struct berlin_pwm_chip *pwm = dev_get_drvdata(dev);
	unsigned int i;
	int ret;

	ret = clk_prepare_enable(pwm->clk);
	if (ret)
		return ret;

	for (i = 0; i < pwm->chip.npwm; i++) {
		struct berlin_pwm_channel *channel;

		channel = pwm_get_chip_data(&pwm->chip.pwms[i]);
		if (!channel)
			continue;

		berlin_pwm_writel(pwm, i, channel->ctrl, BERLIN_PWM_CONTROL);
		berlin_pwm_writel(pwm, i, channel->duty, BERLIN_PWM_DUTY);
		berlin_pwm_writel(pwm, i, channel->tcnt, BERLIN_PWM_TCNT);
		berlin_pwm_writel(pwm, i, channel->enable, BERLIN_PWM_ENABLE);
	}

	return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(berlin_pwm_pm_ops, berlin_pwm_suspend,
			 berlin_pwm_resume);

static struct platform_driver berlin_pwm_driver = {
	.probe = berlin_pwm_probe,
	.remove = berlin_pwm_remove,
	.driver = {
		.name = "berlin-pwm",
		.of_match_table = berlin_pwm_match,
		.pm = &berlin_pwm_pm_ops,
	},
};
module_platform_driver(berlin_pwm_driver);

MODULE_AUTHOR("Antoine Tenart <antoine.tenart@free-electrons.com>");
MODULE_DESCRIPTION("Marvell Berlin PWM driver");
MODULE_LICENSE("GPL v2");