[v5,1/3] 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>
---
 drivers/power/reset/Kconfig              |  7 ++
 drivers/power/reset/Makefile             |  1 +
 drivers/power/reset/regulator-poweroff.c | 82 ++++++++++++++++++++++++
 3 files changed, 90 insertions(+)
 create mode 100644 drivers/power/reset/regulator-poweroff.c

Hi,

On Fri, Dec 11, 2020 at 04:14:43PM +0100, Michael Klein wrote:
> 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>
> ---

Thanks, queued.

-- Sebastian

>  drivers/power/reset/Kconfig              |  7 ++
>  drivers/power/reset/Makefile             |  1 +
>  drivers/power/reset/regulator-poweroff.c | 82 ++++++++++++++++++++++++
>  3 files changed, 90 insertions(+)
>  create mode 100644 drivers/power/reset/regulator-poweroff.c
> 
> diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
> index d55b3727e00e..b22c4fdb2561 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
> +	  power regulator 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..f697088e0ad1
> --- /dev/null
> +++ b/drivers/power/reset/regulator-poweroff.c
> @@ -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");
> -- 
> 2.29.2
> 
> 
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> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Hi Sebastian,

On Sun, Dec 13, 2020 at 12:41:16AM +0100, Sebastian Reichel wrote:
> Hi,

> 

> On Fri, Dec 11, 2020 at 04:14:43PM +0100, Michael Klein wrote:

> > 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>

> > ---

> 

> Thanks, queued.


Did you also merge the binding?

Maxime

Hi Maxime,

On Mon, Dec 14, 2020 at 11:02:04AM +0100, Maxime Ripard wrote:
> Hi Sebastian,

> 

> On Sun, Dec 13, 2020 at 12:41:16AM +0100, Sebastian Reichel wrote:

> > Hi,

> > 

> > On Fri, Dec 11, 2020 at 04:14:43PM +0100, Michael Klein wrote:

> > > 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>

> > > ---

> > 

> > Thanks, queued.

> 

> Did you also merge the binding?


Yes.

-- Sebastian