Home Home > GIT Browse
summaryrefslogtreecommitdiff
blob: 7551253ada32b701ff82f9cbb8c5ecbc7d23b4c7 (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * TI/National Semiconductor LP3943 PWM driver
 *
 * Copyright 2013 Texas Instruments
 *
 * Author: Milo Kim <milo.kim@ti.com>
 */

#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/mfd/lp3943.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/slab.h>

#define LP3943_MAX_DUTY			255
#define LP3943_MIN_PERIOD		6250
#define LP3943_MAX_PERIOD		1600000

struct lp3943_pwm {
	struct pwm_chip chip;
	struct lp3943 *lp3943;
	struct lp3943_platform_data *pdata;
};

static inline struct lp3943_pwm *to_lp3943_pwm(struct pwm_chip *_chip)
{
	return container_of(_chip, struct lp3943_pwm, chip);
}

static struct lp3943_pwm_map *
lp3943_pwm_request_map(struct lp3943_pwm *lp3943_pwm, int hwpwm)
{
	struct lp3943_platform_data *pdata = lp3943_pwm->pdata;
	struct lp3943 *lp3943 = lp3943_pwm->lp3943;
	struct lp3943_pwm_map *pwm_map;
	int i, offset;

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

	pwm_map->output = pdata->pwms[hwpwm]->output;
	pwm_map->num_outputs = pdata->pwms[hwpwm]->num_outputs;

	for (i = 0; i < pwm_map->num_outputs; i++) {
		offset = pwm_map->output[i];

		/* Return an error if the pin is already assigned */
		if (test_and_set_bit(offset, &lp3943->pin_used)) {
			kfree(pwm_map);
			return ERR_PTR(-EBUSY);
		}
	}

	return pwm_map;
}

static int lp3943_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
	struct lp3943_pwm_map *pwm_map;

	pwm_map = lp3943_pwm_request_map(lp3943_pwm, pwm->hwpwm);
	if (IS_ERR(pwm_map))
		return PTR_ERR(pwm_map);

	return pwm_set_chip_data(pwm, pwm_map);
}

static void lp3943_pwm_free_map(struct lp3943_pwm *lp3943_pwm,
				struct lp3943_pwm_map *pwm_map)
{
	struct lp3943 *lp3943 = lp3943_pwm->lp3943;
	int i, offset;

	for (i = 0; i < pwm_map->num_outputs; i++) {
		offset = pwm_map->output[i];
		clear_bit(offset, &lp3943->pin_used);
	}

	kfree(pwm_map);
}

static void lp3943_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
	struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);

	lp3943_pwm_free_map(lp3943_pwm, pwm_map);
}

static int lp3943_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
			     int duty_ns, int period_ns)
{
	struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
	struct lp3943 *lp3943 = lp3943_pwm->lp3943;
	u8 val, reg_duty, reg_prescale;
	int err;

	/*
	 * How to configure the LP3943 PWMs
	 *
	 * 1) Period = 6250 ~ 1600000
	 * 2) Prescale = period / 6250 -1
	 * 3) Duty = input duty
	 *
	 * Prescale and duty are register values
	 */

	if (pwm->hwpwm == 0) {
		reg_prescale = LP3943_REG_PRESCALE0;
		reg_duty     = LP3943_REG_PWM0;
	} else {
		reg_prescale = LP3943_REG_PRESCALE1;
		reg_duty     = LP3943_REG_PWM1;
	}

	period_ns = clamp(period_ns, LP3943_MIN_PERIOD, LP3943_MAX_PERIOD);
	val       = (u8)(period_ns / LP3943_MIN_PERIOD - 1);

	err = lp3943_write_byte(lp3943, reg_prescale, val);
	if (err)
		return err;

	val = (u8)(duty_ns * LP3943_MAX_DUTY / period_ns);

	return lp3943_write_byte(lp3943, reg_duty, val);
}

static int lp3943_pwm_set_mode(struct lp3943_pwm *lp3943_pwm,
			       struct lp3943_pwm_map *pwm_map,
			       u8 val)
{
	struct lp3943 *lp3943 = lp3943_pwm->lp3943;
	const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;
	int i, index, err;

	for (i = 0; i < pwm_map->num_outputs; i++) {
		index = pwm_map->output[i];
		err = lp3943_update_bits(lp3943, mux[index].reg,
					 mux[index].mask,
					 val << mux[index].shift);
		if (err)
			return err;
	}

	return 0;
}

static int lp3943_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
	struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
	u8 val;

	if (pwm->hwpwm == 0)
		val = LP3943_DIM_PWM0;
	else
		val = LP3943_DIM_PWM1;

	/*
	 * Each PWM generator is set to control any of outputs of LP3943.
	 * To enable/disable the PWM, these output pins should be configured.
	 */

	return lp3943_pwm_set_mode(lp3943_pwm, pwm_map, val);
}

static void lp3943_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
	struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);

	/*
	 * LP3943 outputs are open-drain, so the pin should be configured
	 * when the PWM is disabled.
	 */

	lp3943_pwm_set_mode(lp3943_pwm, pwm_map, LP3943_GPIO_OUT_HIGH);
}

static const struct pwm_ops lp3943_pwm_ops = {
	.request	= lp3943_pwm_request,
	.free		= lp3943_pwm_free,
	.config		= lp3943_pwm_config,
	.enable		= lp3943_pwm_enable,
	.disable	= lp3943_pwm_disable,
	.owner		= THIS_MODULE,
};

static int lp3943_pwm_parse_dt(struct device *dev,
			       struct lp3943_pwm *lp3943_pwm)
{
	static const char * const name[] = { "ti,pwm0", "ti,pwm1", };
	struct device_node *node = dev->of_node;
	struct lp3943_platform_data *pdata;
	struct lp3943_pwm_map *pwm_map;
	enum lp3943_pwm_output *output;
	int i, err, proplen, count = 0;
	u32 num_outputs;

	if (!node)
		return -EINVAL;

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

	/*
	 * Read the output map configuration from the device tree.
	 * Each of the two PWM generators can drive zero or more outputs.
	 */

	for (i = 0; i < LP3943_NUM_PWMS; i++) {
		if (!of_get_property(node, name[i], &proplen))
			continue;

		num_outputs = proplen / sizeof(u32);
		if (num_outputs == 0)
			continue;

		output = devm_kcalloc(dev, num_outputs, sizeof(*output),
				      GFP_KERNEL);
		if (!output)
			return -ENOMEM;

		err = of_property_read_u32_array(node, name[i], output,
						 num_outputs);
		if (err)
			return err;

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

		pwm_map->output = output;
		pwm_map->num_outputs = num_outputs;
		pdata->pwms[i] = pwm_map;

		count++;
	}

	if (count == 0)
		return -ENODATA;

	lp3943_pwm->pdata = pdata;
	return 0;
}

static int lp3943_pwm_probe(struct platform_device *pdev)
{
	struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent);
	struct lp3943_pwm *lp3943_pwm;
	int ret;

	lp3943_pwm = devm_kzalloc(&pdev->dev, sizeof(*lp3943_pwm), GFP_KERNEL);
	if (!lp3943_pwm)
		return -ENOMEM;

	lp3943_pwm->pdata = lp3943->pdata;
	if (!lp3943_pwm->pdata) {
		if (IS_ENABLED(CONFIG_OF))
			ret = lp3943_pwm_parse_dt(&pdev->dev, lp3943_pwm);
		else
			ret = -ENODEV;

		if (ret)
			return ret;
	}

	lp3943_pwm->lp3943 = lp3943;
	lp3943_pwm->chip.dev = &pdev->dev;
	lp3943_pwm->chip.ops = &lp3943_pwm_ops;
	lp3943_pwm->chip.npwm = LP3943_NUM_PWMS;

	platform_set_drvdata(pdev, lp3943_pwm);

	return pwmchip_add(&lp3943_pwm->chip);
}

static int lp3943_pwm_remove(struct platform_device *pdev)
{
	struct lp3943_pwm *lp3943_pwm = platform_get_drvdata(pdev);

	return pwmchip_remove(&lp3943_pwm->chip);
}

#ifdef CONFIG_OF
static const struct of_device_id lp3943_pwm_of_match[] = {
	{ .compatible = "ti,lp3943-pwm", },
	{ }
};
MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match);
#endif

static struct platform_driver lp3943_pwm_driver = {
	.probe = lp3943_pwm_probe,
	.remove = lp3943_pwm_remove,
	.driver = {
		.name = "lp3943-pwm",
		.of_match_table = of_match_ptr(lp3943_pwm_of_match),
	},
};
module_platform_driver(lp3943_pwm_driver);

MODULE_DESCRIPTION("LP3943 PWM driver");
MODULE_ALIAS("platform:lp3943-pwm");
MODULE_AUTHOR("Milo Kim");
MODULE_LICENSE("GPL");