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/*
* fixed.c
*
* Copyright 2008 Wolfson Microelectronics PLC.
*
* Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
*
* Copyright (c) 2009 Nokia Corporation
* Roger Quadros <ext-roger.quadros@nokia.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This is useful for systems with mixed controllable and
* non-controllable regulators, as well as for allowing testing on
* systems with no controllable regulators.
*/
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/fixed.h>
#include <linux/gpio.h>
#include <linux/delay.h>
struct fixed_voltage_data {
struct regulator_desc desc;
struct regulator_dev *dev;
int microvolts;
int gpio;
unsigned startup_delay;
unsigned enable_high:1;
unsigned is_enabled:1;
};
static int fixed_voltage_is_enabled(struct regulator_dev *dev)
{
struct fixed_voltage_data *data = rdev_get_drvdata(dev);
return data->is_enabled;
}
static int fixed_voltage_enable(struct regulator_dev *dev)
{
struct fixed_voltage_data *data = rdev_get_drvdata(dev);
if (gpio_is_valid(data->gpio)) {
gpio_set_value_cansleep(data->gpio, data->enable_high);
data->is_enabled = 1;
if (data->startup_delay)
udelay(data->startup_delay);
}
return 0;
}
static int fixed_voltage_disable(struct regulator_dev *dev)
{
struct fixed_voltage_data *data = rdev_get_drvdata(dev);
if (gpio_is_valid(data->gpio)) {
gpio_set_value_cansleep(data->gpio, !data->enable_high);
data->is_enabled = 0;
}
return 0;
}
static int fixed_voltage_get_voltage(struct regulator_dev *dev)
{
struct fixed_voltage_data *data = rdev_get_drvdata(dev);
return data->microvolts;
}
static int fixed_voltage_list_voltage(struct regulator_dev *dev,
unsigned selector)
{
struct fixed_voltage_data *data = rdev_get_drvdata(dev);
if (selector != 0)
return -EINVAL;
return data->microvolts;
}
static struct regulator_ops fixed_voltage_ops = {
.is_enabled = fixed_voltage_is_enabled,
.enable = fixed_voltage_enable,
.disable = fixed_voltage_disable,
.get_voltage = fixed_voltage_get_voltage,
.list_voltage = fixed_voltage_list_voltage,
};
static int regulator_fixed_voltage_probe(struct platform_device *pdev)
{
struct fixed_voltage_config *config = pdev->dev.platform_data;
struct fixed_voltage_data *drvdata;
int ret;
drvdata = kzalloc(sizeof(struct fixed_voltage_data), GFP_KERNEL);
if (drvdata == NULL) {
dev_err(&pdev->dev, "Failed to allocate device data\n");
ret = -ENOMEM;
goto err;
}
drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
if (drvdata->desc.name == NULL) {
dev_err(&pdev->dev, "Failed to allocate supply name\n");
ret = -ENOMEM;
goto err;
}
drvdata->desc.type = REGULATOR_VOLTAGE;
drvdata->desc.owner = THIS_MODULE;
drvdata->desc.ops = &fixed_voltage_ops;
drvdata->desc.n_voltages = 1;
drvdata->microvolts = config->microvolts;
drvdata->gpio = config->gpio;
drvdata->startup_delay = config->startup_delay;
if (gpio_is_valid(config->gpio)) {
drvdata->enable_high = config->enable_high;
/* FIXME: Remove below print warning
*
* config->gpio must be set to -EINVAL by platform code if
* GPIO control is not required. However, early adopters
* not requiring GPIO control may forget to initialize
* config->gpio to -EINVAL. This will cause GPIO 0 to be used
* for GPIO control.
*
* This warning will be removed once there are a couple of users
* for this driver.
*/
if (!config->gpio)
dev_warn(&pdev->dev,
"using GPIO 0 for regulator enable control\n");
ret = gpio_request(config->gpio, config->supply_name);
if (ret) {
dev_err(&pdev->dev,
"Could not obtain regulator enable GPIO %d: %d\n",
config->gpio, ret);
goto err_name;
}
/* set output direction without changing state
* to prevent glitch
*/
drvdata->is_enabled = config->enabled_at_boot;
ret = drvdata->is_enabled ?
config->enable_high : !config->enable_high;
ret = gpio_direction_output(config->gpio, ret);
if (ret) {
dev_err(&pdev->dev,
"Could not configure regulator enable GPIO %d direction: %d\n",
config->gpio, ret);
goto err_gpio;
}
} else {
/* Regulator without GPIO control is considered
* always enabled
*/
drvdata->is_enabled = 1;
}
drvdata->dev = regulator_register(&drvdata->desc, &pdev->dev,
config->init_data, drvdata);
if (IS_ERR(drvdata->dev)) {
ret = PTR_ERR(drvdata->dev);
dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
goto err_gpio;
}
platform_set_drvdata(pdev, drvdata);
dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
drvdata->microvolts);
return 0;
err_gpio:
if (gpio_is_valid(config->gpio))
gpio_free(config->gpio);
err_name:
kfree(drvdata->desc.name);
err:
kfree(drvdata);
return ret;
}
static int regulator_fixed_voltage_remove(struct platform_device *pdev)
{
struct fixed_voltage_data *drvdata = platform_get_drvdata(pdev);
regulator_unregister(drvdata->dev);
if (gpio_is_valid(drvdata->gpio))
gpio_free(drvdata->gpio);
kfree(drvdata->desc.name);
kfree(drvdata);
return 0;
}
static struct platform_driver regulator_fixed_voltage_driver = {
.probe = regulator_fixed_voltage_probe,
.remove = regulator_fixed_voltage_remove,
.driver = {
.name = "reg-fixed-voltage",
},
};
static int __init regulator_fixed_voltage_init(void)
{
return platform_driver_register(®ulator_fixed_voltage_driver);
}
subsys_initcall(regulator_fixed_voltage_init);
static void __exit regulator_fixed_voltage_exit(void)
{
platform_driver_unregister(®ulator_fixed_voltage_driver);
}
module_exit(regulator_fixed_voltage_exit);
MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
MODULE_DESCRIPTION("Fixed voltage regulator");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:reg-fixed-voltage");
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