[PATCH 4/5] power: reset: add GPIO restart driver

[Lars Pedersen]

On Sat, 10 Apr 2021 at 12:37, Ahmad Fatoum <ahmad at a3f.at> wrote:
>
> This is a straight port from Linux v5.11.
>
> Signed-off-by: Ahmad Fatoum <ahmad at a3f.at>
Tested-by: Lars Pedersen <lapeddk at gmail.com>

Tested on imx7-tqma7 platform.

> ---
>  drivers/power/reset/Kconfig        |  8 +++
>  drivers/power/reset/Makefile       |  1 +
>  drivers/power/reset/gpio-restart.c | 99 ++++++++++++++++++++++++++++++
>  3 files changed, 108 insertions(+)
>  create mode 100644 drivers/power/reset/gpio-restart.c
>
> diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
> index cadcc0b13f2f..dec1482ccd0c 100644
> --- a/drivers/power/reset/Kconfig
> +++ b/drivers/power/reset/Kconfig
> @@ -36,3 +36,11 @@ config POWER_RESET_GPIO
>           This driver supports turning off your board via a GPIO line.
>           If your board needs a GPIO high/low to power down, say Y and
>           create a binding in your devicetree.
> +
> +config POWER_RESET_GPIO_RESTART
> +       bool "GPIO restart driver"
> +       depends on OF_GPIO
> +       help
> +         This driver supports restarting your board via a GPIO line.
> +         If your board needs a GPIO high/low to restart, say Y and
> +         create a binding in your devicetree.
> diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
> index 438c85970028..33d29d2d9546 100644
> --- a/drivers/power/reset/Makefile
> +++ b/drivers/power/reset/Makefile
> @@ -4,3 +4,4 @@ obj-$(CONFIG_SYSCON_REBOOT_MODE) += syscon-reboot-mode.o
>  obj-$(CONFIG_POWER_RESET_SYSCON) += syscon-reboot.o
>  obj-$(CONFIG_POWER_RESET_SYSCON_POWEROFF) += syscon-poweroff.o
>  obj-$(CONFIG_POWER_RESET_GPIO) += gpio-poweroff.o
> +obj-$(CONFIG_POWER_RESET_GPIO_RESTART) += gpio-restart.o
> diff --git a/drivers/power/reset/gpio-restart.c b/drivers/power/reset/gpio-restart.c
> new file mode 100644
> index 000000000000..72c690a3cf4c
> --- /dev/null
> +++ b/drivers/power/reset/gpio-restart.c
> @@ -0,0 +1,99 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Toggles a GPIO pin to restart a device
> + *
> + * Copyright (C) 2014 Google, Inc.
> + *
> + * Based on the gpio-poweroff driver.
> + */
> +#include <common.h>
> +#include <driver.h>
> +#include <restart.h>
> +#include <gpiod.h>
> +
> +struct gpio_restart {
> +       int reset_gpio;
> +       struct restart_handler restart_handler;
> +       u32 active_delay_ms;
> +       u32 inactive_delay_ms;
> +       u32 wait_delay_ms;
> +};
> +
> +static void __noreturn gpio_restart_handle(struct restart_handler *this)
> +{
> +       struct gpio_restart *gpio_restart =
> +               container_of(this, struct gpio_restart, restart_handler);
> +
> +       /* drive it active, also inactive->active edge */
> +       gpio_direction_active(gpio_restart->reset_gpio, true);
> +       mdelay(gpio_restart->active_delay_ms);
> +
> +       /* drive inactive, also active->inactive edge */
> +       gpio_set_active(gpio_restart->reset_gpio, false);
> +       mdelay(gpio_restart->inactive_delay_ms);
> +
> +       /* drive it active, also inactive->active edge */
> +       gpio_set_active(gpio_restart->reset_gpio, true);
> +
> +       /* give it some time */
> +       mdelay(gpio_restart->wait_delay_ms);
> +
> +       mdelay(1000);
> +
> +       panic("Unable to restart system\n");
> +}
> +
> +static int gpio_restart_probe(struct device_d *dev)
> +{
> +       struct device_node *np = dev->device_node;
> +       struct gpio_restart *gpio_restart;
> +       bool open_source = false;
> +       u32 property;
> +       int ret;
> +
> +       gpio_restart = xzalloc(sizeof(*gpio_restart));
> +
> +       open_source = of_property_read_bool(np, "open-source");
> +
> +       gpio_restart->reset_gpio = gpiod_get(dev, NULL,
> +                       open_source ? GPIOD_IN : GPIOD_OUT_LOW);
> +       ret = gpio_restart->reset_gpio;
> +       if (ret < 0) {
> +               if (ret != -EPROBE_DEFER)
> +                       dev_err(dev, "Could not get reset GPIO\n");
> +               return ret;
> +       }
> +
> +       gpio_restart->restart_handler.restart = gpio_restart_handle;
> +       gpio_restart->restart_handler.name = "gpio-restart";
> +       gpio_restart->restart_handler.priority = 129;
> +       gpio_restart->active_delay_ms = 100;
> +       gpio_restart->inactive_delay_ms = 100;
> +       gpio_restart->wait_delay_ms = 3000;
> +
> +       ret = of_property_read_u32(dev->device_node, "priority", &property);
> +       if (!ret)
> +               gpio_restart->restart_handler.priority = property;
> +
> +       of_property_read_u32(np, "active-delay", &gpio_restart->active_delay_ms);
> +       of_property_read_u32(np, "inactive-delay", &gpio_restart->inactive_delay_ms);
> +       of_property_read_u32(np, "wait-delay", &gpio_restart->wait_delay_ms);
> +
> +       return restart_handler_register(&gpio_restart->restart_handler);
> +}
> +
> +static const struct of_device_id of_gpio_restart_match[] = {
> +       { .compatible = "gpio-restart", },
> +       {},
> +};
> +
> +static struct driver_d gpio_restart_driver = {
> +       .name = "restart-gpio",
> +       .of_compatible = of_gpio_restart_match,
> +       .probe = gpio_restart_probe,
> +};
> +device_platform_driver(gpio_restart_driver);
> +
> +MODULE_AUTHOR("David Riley <davidriley at chromium.org>");
> +MODULE_DESCRIPTION("GPIO restart driver");
> +MODULE_LICENSE("GPL");
> --
> 2.30.0
>
>
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