On Tue, Dec 08, 2020 at 11:10:52AM +0100, Maxime Ripard wrote:
On Mon, Dec 07, 2020 at 03:27:54PM +0100, Michael Klein wrote:This driver registers a pm_power_off function to disable a set of regulators defined in the devicetree to turn off the board. Signed-off-by: Michael Klein <michael@xxxxxxxxxxxx> --- drivers/power/reset/Kconfig | 7 ++ drivers/power/reset/Makefile | 1 + drivers/power/reset/regulator-poweroff.c | 107 +++++++++++++++++++++++ 3 files changed, 115 insertions(+) create mode 100644 drivers/power/reset/regulator-poweroff.c diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig index d55b3727e00e..ae6cb7b0bd4d 100644 --- a/drivers/power/reset/Kconfig +++ b/drivers/power/reset/Kconfig @@ -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 set + of regulators defined in the devicetree. + config POWER_RESET_RESTART bool "Restart power-off driver" help diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile index c51eceba9ea3..9dc49d3a57ff 100644 --- a/drivers/power/reset/Makefile +++ b/drivers/power/reset/Makefile @@ -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 diff --git a/drivers/power/reset/regulator-poweroff.c b/drivers/power/reset/regulator-poweroff.c new file mode 100644 index 000000000000..df2ca4fdcc49 --- /dev/null +++ b/drivers/power/reset/regulator-poweroff.c @@ -0,0 +1,107 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Force-disables a regulator to power down a device + * + * Michael Klein <michael@xxxxxxxxxxxx> + * + * Copyright (C) 2020 Michael Klein + * + * Based on the gpio-poweroff driver. + */ +#include <linux/delay.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/regulator/consumer.h> + +#define DEFAULT_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 **poweroff_regulators; +static u32 timeout = DEFAULT_TIMEOUT_MS; + +static void regulator_poweroff_do_poweroff(void) +{ + struct regulator **it; + + if (poweroff_regulators) + for (it = poweroff_regulators; *it; ++it) + if (regulator_is_enabled(*it)) + regulator_force_disable(*it); + + /* give it some time */ + mdelay(timeout); + + WARN_ON(1); +} + +static int regulator_poweroff_probe(struct platform_device *pdev) +{ + int count; + const char *name; + struct regulator **it; + struct property *prop; + struct device_node *node = pdev->dev.of_node; + + /* 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; + } + + count = of_property_count_strings(node, "regulator-names"); + if (count <= 0) + return -ENOENT; + + poweroff_regulators = devm_kcalloc(&pdev->dev, count + 1, + sizeof(struct regulator *), GFP_KERNEL); + + it = poweroff_regulators; + of_property_for_each_string(node, "regulator-names", prop, name) { + *it = devm_regulator_get(&pdev->dev, name); + if (IS_ERR(*it)) + return PTR_ERR(*it); + it++; + } + + of_property_read_u32(node, "timeout-ms", &timeout); + + 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);Since this can't be compiled as a module, you can use module_platform_driver_probe instead.
actually no, as platform_driver_probe() does not support deferred probing and the regulator might not be available during regulator_poweroff_probe() yet:
# dmesg | grep poweroff [ 0.788135] poweroff-regulator poweroff: probe deferral not supported -- Michael
