83 lines
2.0 KiB
C
83 lines
2.0 KiB
C
// 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", },
|
|
{},
|
|
};
|
|
|
|
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");
|