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/*
* 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.
*/
#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>
struct pwm_regulator_data {
struct regulator_desc desc;
struct pwm_voltages *duty_cycle_table;
struct pwm_device *pwm;
bool enabled;
int state;
};
struct pwm_voltages {
unsigned int uV;
unsigned int dutycycle;
};
static int pwm_regulator_get_voltage_sel(struct regulator_dev *dev)
{
struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
return drvdata->state;
}
static int pwm_regulator_set_voltage_sel(struct regulator_dev *dev,
unsigned selector)
{
struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
unsigned int pwm_reg_period;
int dutycycle;
int ret;
pwm_reg_period = pwm_get_period(drvdata->pwm);
dutycycle = (pwm_reg_period *
drvdata->duty_cycle_table[selector].dutycycle) / 100;
ret = pwm_config(drvdata->pwm, dutycycle, pwm_reg_period);
if (ret) {
dev_err(&dev->dev, "Failed to configure PWM\n");
return ret;
}
drvdata->state = selector;
if (!drvdata->enabled) {
ret = pwm_enable(drvdata->pwm);
if (ret) {
dev_err(&dev->dev, "Failed to enable PWM\n");
return ret;
}
drvdata->enabled = true;
}
return 0;
}
static int pwm_regulator_list_voltage(struct regulator_dev *dev,
unsigned selector)
{
struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
if (selector >= drvdata->desc.n_voltages)
return -EINVAL;
return drvdata->duty_cycle_table[selector].uV;
}
static struct regulator_ops pwm_regulator_voltage_ops = {
.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,
};
static const struct regulator_desc pwm_regulator_desc = {
.name = "pwm-regulator",
.ops = &pwm_regulator_voltage_ops,
.type = REGULATOR_VOLTAGE,
.owner = THIS_MODULE,
.supply_name = "pwm",
};
static int pwm_regulator_probe(struct platform_device *pdev)
{
struct pwm_regulator_data *drvdata;
struct property *prop;
struct regulator_dev *regulator;
struct regulator_config config = { };
struct device_node *np = pdev->dev.of_node;
int length, ret;
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;
memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(pwm_regulator_desc));
/* determine the number of voltage-table */
prop = of_find_property(np, "voltage-table", &length);
if (!prop) {
dev_err(&pdev->dev, "No voltage-table\n");
return -EINVAL;
}
if ((length < sizeof(*drvdata->duty_cycle_table)) ||
(length % sizeof(*drvdata->duty_cycle_table))) {
dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n",
length);
return -EINVAL;
}
drvdata->desc.n_voltages = length / sizeof(*drvdata->duty_cycle_table);
drvdata->duty_cycle_table = devm_kzalloc(&pdev->dev,
length, GFP_KERNEL);
if (!drvdata->duty_cycle_table)
return -ENOMEM;
/* read voltage table from DT property */
ret = of_property_read_u32_array(np, "voltage-table",
(u32 *)drvdata->duty_cycle_table,
length / sizeof(u32));
if (ret < 0) {
dev_err(&pdev->dev, "read voltage-table failed\n");
return ret;
}
config.init_data = of_get_regulator_init_data(&pdev->dev, np,
&drvdata->desc);
if (!config.init_data)
return -ENOMEM;
config.of_node = np;
config.dev = &pdev->dev;
config.driver_data = drvdata;
drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
if (IS_ERR(drvdata->pwm)) {
dev_err(&pdev->dev, "Failed to get PWM\n");
return PTR_ERR(drvdata->pwm);
}
regulator = devm_regulator_register(&pdev->dev,
&drvdata->desc, &config);
if (IS_ERR(regulator)) {
dev_err(&pdev->dev, "Failed to register regulator %s\n",
drvdata->desc.name);
return PTR_ERR(regulator);
}
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",
.owner = THIS_MODULE,
.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");
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