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power: reset: new driver regulator-poweroff 

This driver registers a pm_power_off function to turn off the board
by force-disabling a devicetree-defined regulator.

Signed-off-by: Michael Klein <michael@fossekall.de>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
zero-sugar-mainline-defconfig
Michael Klein 2020-12-11 16:14:43 +01:00 committed by Sebastian Reichel
parent 36f1de0d5c
commit ec66096b76
3 changed files with 90 additions and 0 deletions
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7
drivers/power/reset/Kconfig
View File

@ -177,6 +177,13 @@ config POWER_RESET_QNAP
Say Y if you have a QNAP NAS.
config POWER_RESET_REGULATOR
bool "Regulator subsystem power-off driver"
depends on OF && REGULATOR
help
This driver supports turning off your board by disabling a
power regulator defined in the devicetree.
config POWER_RESET_RESTART
bool "Restart power-off driver"
help

1
drivers/power/reset/Makefile
View File

@ -19,6 +19,7 @@ obj-$(CONFIG_POWER_RESET_OCELOT_RESET) += ocelot-reset.o
obj-$(CONFIG_POWER_RESET_PIIX4_POWEROFF) += piix4-poweroff.o
obj-$(CONFIG_POWER_RESET_LTC2952) += ltc2952-poweroff.o
obj-$(CONFIG_POWER_RESET_QNAP) += qnap-poweroff.o
obj-$(CONFIG_POWER_RESET_REGULATOR) += regulator-poweroff.o
obj-$(CONFIG_POWER_RESET_RESTART) += restart-poweroff.o
obj-$(CONFIG_POWER_RESET_ST) += st-poweroff.o
obj-$(CONFIG_POWER_RESET_VERSATILE) += arm-versatile-reboot.o

82
drivers/power/reset/regulator-poweroff.c 100644
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@ -0,0 +1,82 @@
// 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 = &regulator_poweroff_do_poweroff;
return 0;
}
static int regulator_poweroff_remove(__maybe_unused struct platform_device *pdev)
{
if (pm_power_off == &regulator_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");