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// SPDX-License-Identifier: GPL-2.0-only
/*
* Force-disables a regulator to power down a device
*
* Michael Klein <michael@fossekall.de>
*
* Copyright (C) 2020 Michael Klein
*
* Based on the gpio-poweroff driver.
*/
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/regulator/consumer.h>
#define TIMEOUT_MS 3000
/*
* Hold configuration here, cannot be more than one instance of the driver
* since pm_power_off itself is global.
*/
static struct regulator *cpu_regulator;
static void regulator_poweroff_do_poweroff(void)
{
if (cpu_regulator && regulator_is_enabled(cpu_regulator))
regulator_force_disable(cpu_regulator);
/* give it some time */
mdelay(TIMEOUT_MS);
WARN_ON(1);
}
static int regulator_poweroff_probe(struct platform_device *pdev)
{
/* If a pm_power_off function has already been added, leave it alone */
if (pm_power_off != NULL) {
dev_err(&pdev->dev,
"%s: pm_power_off function already registered\n",
__func__);
return -EBUSY;
}
cpu_regulator = devm_regulator_get(&pdev->dev, "cpu");
if (IS_ERR(cpu_regulator))
return PTR_ERR(cpu_regulator);
pm_power_off = ®ulator_poweroff_do_poweroff;
return 0;
}
static int regulator_poweroff_remove(__maybe_unused struct platform_device *pdev)
{
if (pm_power_off == ®ulator_poweroff_do_poweroff)
pm_power_off = NULL;
return 0;
}
static const struct of_device_id of_regulator_poweroff_match[] = {
{ .compatible = "regulator-poweroff", },
{},
};
MODULE_DEVICE_TABLE(of, of_regulator_poweroff_match);
static struct platform_driver regulator_poweroff_driver = {
.probe = regulator_poweroff_probe,
.remove = regulator_poweroff_remove,
.driver = {
.name = "poweroff-regulator",
.of_match_table = of_regulator_poweroff_match,
},
};
module_platform_driver(regulator_poweroff_driver);
MODULE_AUTHOR("Michael Klein <michael@fossekall.de>");
MODULE_DESCRIPTION("Regulator poweroff driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:poweroff-regulator");
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