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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/delay.h>
#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 {
/* Shared */
struct pwm_device *pwm;
/* Voltage table */
struct pwm_voltages *duty_cycle_table;
int state;
/* Continuous voltage */
u32 max_duty_cycle;
int volt_uV;
};
struct pwm_voltages {
unsigned int uV;
unsigned int dutycycle;
};
/**
* Voltage table call-backs
*/
static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev)
{
struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
return drvdata->state;
}
static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev,
unsigned selector)
{
struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
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(&rdev->dev, "Failed to configure PWM\n");
return ret;
}
drvdata->state = selector;
ret = pwm_enable(drvdata->pwm);
if (ret) {
dev_err(&rdev->dev, "Failed to enable PWM\n");
return ret;
}
return 0;
}
static int pwm_regulator_list_voltage(struct regulator_dev *rdev,
unsigned selector)
{
struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
if (selector >= rdev->desc->n_voltages)
return -EINVAL;
return drvdata->duty_cycle_table[selector].uV;
}
/**
* Continuous voltage call-backs
*/
static int pwm_voltage_to_duty_cycle(struct regulator_dev *rdev, int req_uV)
{
int min_uV = rdev->constraints->min_uV;
int max_uV = rdev->constraints->max_uV;
int diff = max_uV - min_uV;
return 100 - ((((req_uV * 100) - (min_uV * 100)) / diff));
}
static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
{
struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
return drvdata->volt_uV;
}
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;
int duty_cycle;
int ret;
duty_cycle = pwm_voltage_to_duty_cycle(rdev, min_uV);
ret = pwm_config(drvdata->pwm,
(drvdata->pwm->period / 100) * duty_cycle,
drvdata->pwm->period);
if (ret) {
dev_err(&rdev->dev, "Failed to configure PWM\n");
return ret;
}
ret = pwm_enable(drvdata->pwm);
if (ret) {
dev_err(&rdev->dev, "Failed to enable PWM\n");
return ret;
}
drvdata->volt_uV = min_uV;
/* Delay required by PWM regulator to settle to the new voltage */
usleep_range(ramp_delay, ramp_delay + 1000);
return 0;
}
static struct regulator_ops pwm_regulator_voltage_table_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 struct regulator_ops pwm_regulator_voltage_continuous_ops = {
.get_voltage = pwm_regulator_get_voltage,
.set_voltage = pwm_regulator_set_voltage,
};
static struct regulator_desc pwm_regulator_desc = {
.name = "pwm-regulator",
.type = REGULATOR_VOLTAGE,
.owner = THIS_MODULE,
.supply_name = "pwm",
};
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;
int length;
int ret;
of_find_property(np, "voltage-table", &length);
if ((length < sizeof(*duty_cycle_table)) ||
(length % sizeof(*duty_cycle_table))) {
dev_err(&pdev->dev,
"voltage-table length(%d) is invalid\n",
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) {
dev_err(&pdev->dev, "Failed to read voltage-table\n");
return ret;
}
drvdata->duty_cycle_table = duty_cycle_table;
pwm_regulator_desc.ops = &pwm_regulator_voltage_table_ops;
pwm_regulator_desc.n_voltages = length / sizeof(*duty_cycle_table);
return 0;
}
static int pwm_regulator_init_continuous(struct platform_device *pdev,
struct pwm_regulator_data *drvdata)
{
struct device_node *np = pdev->dev.of_node;
int ret;
ret = of_property_read_u32(np, "max-duty-cycle",
&drvdata->max_duty_cycle);
if (ret) {
dev_err(&pdev->dev, "Failed to read \"pwm-max-value\"\n");
return ret;
}
pwm_regulator_desc.ops = &pwm_regulator_voltage_continuous_ops;
pwm_regulator_desc.continuous_voltage_range = true;
return 0;
}
static int pwm_regulator_probe(struct platform_device *pdev)
{
struct pwm_regulator_data *drvdata;
struct regulator_dev *regulator;
struct regulator_config config = { };
struct device_node *np = pdev->dev.of_node;
int 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;
if (of_find_property(np, "voltage-table", NULL))
ret = pwm_regulator_init_table(pdev, drvdata);
else
ret = pwm_regulator_init_continuous(pdev, drvdata);
if (ret)
return ret;
config.init_data = of_get_regulator_init_data(&pdev->dev, np,
&pwm_regulator_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,
&pwm_regulator_desc, &config);
if (IS_ERR(regulator)) {
dev_err(&pdev->dev, "Failed to register regulator %s\n",
pwm_regulator_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",
.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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