pwm-regulator.c 9.0 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12
/*
 * Regulator driver for PWM Regulators
 *
 * Copyright (C) 2014 - STMicroelectronics Inc.
 *
 * Author: Lee Jones <lee.jones@linaro.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

13
#include <linux/delay.h>
14 15 16 17 18 19 20 21 22
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/regulator/of_regulator.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/pwm.h>
23
#include <linux/gpio/consumer.h>
24 25

struct pwm_regulator_data {
26
	/*  Shared */
27
	struct pwm_device *pwm;
28 29 30

	/* Voltage table */
	struct pwm_voltages *duty_cycle_table;
31 32 33 34 35 36 37

	/* regulator descriptor */
	struct regulator_desc desc;

	/* Regulator ops */
	struct regulator_ops ops;

38
	int state;
39

40 41
	/* Enable GPIO */
	struct gpio_desc *enb_gpio;
42 43 44 45 46 47 48
};

struct pwm_voltages {
	unsigned int uV;
	unsigned int dutycycle;
};

49 50 51
/**
 * Voltage table call-backs
 */
52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69
static void pwm_regulator_init_state(struct regulator_dev *rdev)
{
	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
	struct pwm_state pwm_state;
	unsigned int dutycycle;
	int i;

	pwm_get_state(drvdata->pwm, &pwm_state);
	dutycycle = pwm_get_relative_duty_cycle(&pwm_state, 100);

	for (i = 0; i < rdev->desc->n_voltages; i++) {
		if (dutycycle == drvdata->duty_cycle_table[i].dutycycle) {
			drvdata->state = i;
			return;
		}
	}
}

70
static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev)
71
{
72
	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
73

74 75 76
	if (drvdata->state < 0)
		pwm_regulator_init_state(rdev);

77 78 79
	return drvdata->state;
}

80
static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev,
81 82
					 unsigned selector)
{
83
	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
84
	struct pwm_state pstate;
85 86
	int ret;

87 88 89
	pwm_init_state(drvdata->pwm, &pstate);
	pwm_set_relative_duty_cycle(&pstate,
			drvdata->duty_cycle_table[selector].dutycycle, 100);
90

91
	ret = pwm_apply_state(drvdata->pwm, &pstate);
92
	if (ret) {
93
		dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
94 95 96 97 98 99 100 101
		return ret;
	}

	drvdata->state = selector;

	return 0;
}

102
static int pwm_regulator_list_voltage(struct regulator_dev *rdev,
103 104
				      unsigned selector)
{
105
	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
106

107
	if (selector >= rdev->desc->n_voltages)
108 109 110 111
		return -EINVAL;

	return drvdata->duty_cycle_table[selector].uV;
}
112

113 114 115 116
static int pwm_regulator_enable(struct regulator_dev *dev)
{
	struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);

117 118 119
	if (drvdata->enb_gpio)
		gpiod_set_value_cansleep(drvdata->enb_gpio, 1);

120 121 122 123 124 125 126 127 128
	return pwm_enable(drvdata->pwm);
}

static int pwm_regulator_disable(struct regulator_dev *dev)
{
	struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);

	pwm_disable(drvdata->pwm);

129 130 131
	if (drvdata->enb_gpio)
		gpiod_set_value_cansleep(drvdata->enb_gpio, 0);

132 133 134 135 136 137 138
	return 0;
}

static int pwm_regulator_is_enabled(struct regulator_dev *dev)
{
	struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);

139 140 141
	if (drvdata->enb_gpio && !gpiod_get_value_cansleep(drvdata->enb_gpio))
		return false;

142 143 144
	return pwm_is_enabled(drvdata->pwm);
}

145 146 147
static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
{
	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
148 149 150
	int min_uV = rdev->constraints->min_uV;
	int diff = rdev->constraints->max_uV - min_uV;
	struct pwm_state pstate;
151

152 153 154
	pwm_get_state(drvdata->pwm, &pstate);

	return min_uV + pwm_get_relative_duty_cycle(&pstate, diff);
155 156 157 158 159 160 161 162
}

static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
					int min_uV, int max_uV,
					unsigned *selector)
{
	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
	unsigned int ramp_delay = rdev->constraints->ramp_delay;
163
	unsigned int req_diff = min_uV - rdev->constraints->min_uV;
164
	struct pwm_state pstate;
165
	unsigned int diff;
166
	int old_uV = pwm_regulator_get_voltage(rdev);
167 168
	int ret;

169
	pwm_init_state(drvdata->pwm, &pstate);
170 171
	diff = rdev->constraints->max_uV - rdev->constraints->min_uV;

172 173
	/* We pass diff as the scale to get a uV precision. */
	pwm_set_relative_duty_cycle(&pstate, req_diff, diff);
174

175
	ret = pwm_apply_state(drvdata->pwm, &pstate);
176
	if (ret) {
177
		dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
178 179 180
		return ret;
	}

181 182 183 184 185 186
	if ((ramp_delay == 0) || !pwm_regulator_is_enabled(rdev))
		return 0;

	/* Ramp delay is in uV/uS. Adjust to uS and delay */
	ramp_delay = DIV_ROUND_UP(abs(min_uV - old_uV), ramp_delay);
	usleep_range(ramp_delay, ramp_delay + DIV_ROUND_UP(ramp_delay, 10));
187 188 189 190

	return 0;
}

191
static struct regulator_ops pwm_regulator_voltage_table_ops = {
192 193 194 195
	.set_voltage_sel = pwm_regulator_set_voltage_sel,
	.get_voltage_sel = pwm_regulator_get_voltage_sel,
	.list_voltage    = pwm_regulator_list_voltage,
	.map_voltage     = regulator_map_voltage_iterate,
196 197 198
	.enable          = pwm_regulator_enable,
	.disable         = pwm_regulator_disable,
	.is_enabled      = pwm_regulator_is_enabled,
199 200
};

201 202 203
static struct regulator_ops pwm_regulator_voltage_continuous_ops = {
	.get_voltage = pwm_regulator_get_voltage,
	.set_voltage = pwm_regulator_set_voltage,
204 205 206
	.enable          = pwm_regulator_enable,
	.disable         = pwm_regulator_disable,
	.is_enabled      = pwm_regulator_is_enabled,
207 208
};

209
static struct regulator_desc pwm_regulator_desc = {
210 211 212 213 214 215
	.name		= "pwm-regulator",
	.type		= REGULATOR_VOLTAGE,
	.owner		= THIS_MODULE,
	.supply_name    = "pwm",
};

216 217 218 219 220
static int pwm_regulator_init_table(struct platform_device *pdev,
				    struct pwm_regulator_data *drvdata)
{
	struct device_node *np = pdev->dev.of_node;
	struct pwm_voltages *duty_cycle_table;
221
	unsigned int length = 0;
222 223 224 225 226 227
	int ret;

	of_find_property(np, "voltage-table", &length);

	if ((length < sizeof(*duty_cycle_table)) ||
	    (length % sizeof(*duty_cycle_table))) {
228
		dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n",
229 230 231 232 233 234 235 236 237 238 239 240
			length);
		return -EINVAL;
	}

	duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL);
	if (!duty_cycle_table)
		return -ENOMEM;

	ret = of_property_read_u32_array(np, "voltage-table",
					 (u32 *)duty_cycle_table,
					 length / sizeof(u32));
	if (ret) {
241
		dev_err(&pdev->dev, "Failed to read voltage-table: %d\n", ret);
242 243 244
		return ret;
	}

245
	drvdata->state			= -EINVAL;
246
	drvdata->duty_cycle_table	= duty_cycle_table;
247 248 249 250
	memcpy(&drvdata->ops, &pwm_regulator_voltage_table_ops,
	       sizeof(drvdata->ops));
	drvdata->desc.ops = &drvdata->ops;
	drvdata->desc.n_voltages	= length / sizeof(*duty_cycle_table);
251 252 253 254

	return 0;
}

255 256 257
static int pwm_regulator_init_continuous(struct platform_device *pdev,
					 struct pwm_regulator_data *drvdata)
{
258 259 260 261
	memcpy(&drvdata->ops, &pwm_regulator_voltage_continuous_ops,
	       sizeof(drvdata->ops));
	drvdata->desc.ops = &drvdata->ops;
	drvdata->desc.continuous_voltage_range = true;
262 263 264 265

	return 0;
}

266 267
static int pwm_regulator_probe(struct platform_device *pdev)
{
268
	const struct regulator_init_data *init_data;
269 270 271 272
	struct pwm_regulator_data *drvdata;
	struct regulator_dev *regulator;
	struct regulator_config config = { };
	struct device_node *np = pdev->dev.of_node;
273
	enum gpiod_flags gpio_flags;
274
	int ret;
275 276 277 278 279 280 281 282 283 284

	if (!np) {
		dev_err(&pdev->dev, "Device Tree node missing\n");
		return -EINVAL;
	}

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

285 286
	memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc));

287
	if (of_find_property(np, "voltage-table", NULL))
288
		ret = pwm_regulator_init_table(pdev, drvdata);
289 290 291 292
	else
		ret = pwm_regulator_init_continuous(pdev, drvdata);
	if (ret)
		return ret;
293

294
	init_data = of_get_regulator_init_data(&pdev->dev, np,
295
					       &drvdata->desc);
296
	if (!init_data)
297 298 299 300 301
		return -ENOMEM;

	config.of_node = np;
	config.dev = &pdev->dev;
	config.driver_data = drvdata;
302
	config.init_data = init_data;
303 304 305

	drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
	if (IS_ERR(drvdata->pwm)) {
306 307 308
		ret = PTR_ERR(drvdata->pwm);
		dev_err(&pdev->dev, "Failed to get PWM: %d\n", ret);
		return ret;
309 310
	}

311 312 313 314 315 316 317 318 319 320 321 322
	if (init_data->constraints.boot_on || init_data->constraints.always_on)
		gpio_flags = GPIOD_OUT_HIGH;
	else
		gpio_flags = GPIOD_OUT_LOW;
	drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
						    gpio_flags);
	if (IS_ERR(drvdata->enb_gpio)) {
		ret = PTR_ERR(drvdata->enb_gpio);
		dev_err(&pdev->dev, "Failed to get enable GPIO: %d\n", ret);
		return ret;
	}

323 324 325
	ret = pwm_adjust_config(drvdata->pwm);
	if (ret)
		return ret;
326

327
	regulator = devm_regulator_register(&pdev->dev,
328
					    &drvdata->desc, &config);
329
	if (IS_ERR(regulator)) {
330 331 332 333
		ret = PTR_ERR(regulator);
		dev_err(&pdev->dev, "Failed to register regulator %s: %d\n",
			drvdata->desc.name, ret);
		return ret;
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
	}

	return 0;
}

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

static struct platform_driver pwm_regulator_driver = {
	.driver = {
		.name		= "pwm-regulator",
		.of_match_table = of_match_ptr(pwm_of_match),
	},
	.probe = pwm_regulator_probe,
};

module_platform_driver(pwm_regulator_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
MODULE_DESCRIPTION("PWM Regulator Driver");
MODULE_ALIAS("platform:pwm-regulator");