diff options
| -rw-r--r-- | Documentation/devicetree/bindings/gpio/gpio-restart.txt | 54 | ||||
| -rw-r--r-- | drivers/power/reset/Kconfig | 8 | ||||
| -rw-r--r-- | drivers/power/reset/Makefile | 1 | ||||
| -rw-r--r-- | drivers/power/reset/gpio-restart.c | 149 |
4 files changed, 212 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/gpio/gpio-restart.txt b/Documentation/devicetree/bindings/gpio/gpio-restart.txt new file mode 100644 index 000000000000..af3701bc15c4 --- /dev/null +++ b/Documentation/devicetree/bindings/gpio/gpio-restart.txt @@ -0,0 +1,54 @@ +Drive a GPIO line that can be used to restart the system from a restart +handler. + +This binding supports level and edge triggered reset. At driver load +time, the driver will request the given gpio line and install a restart +handler. If the optional properties 'open-source' is not found, the GPIO line +will be driven in the inactive state. Otherwise its not driven until +the restart is initiated. + +When the system is restarted, the restart handler will be invoked in +priority order. The gpio is configured as an output, and driven active, +triggering a level triggered reset condition. This will also cause an +inactive->active edge condition, triggering positive edge triggered +reset. After a delay specified by active-delay, the GPIO is set to +inactive, thus causing an active->inactive edge, triggering negative edge +triggered reset. After a delay specified by inactive-delay, the GPIO +is driven active again. After a delay specified by wait-delay, the +restart handler completes allowing other restart handlers to be attempted. + +Required properties: +- compatible : should be "gpio-restart". +- gpios : The GPIO to set high/low, see "gpios property" in + Documentation/devicetree/bindings/gpio/gpio.txt. If the pin should be + low to reset the board set it to "Active Low", otherwise set + gpio to "Active High". + +Optional properties: +- open-source : Treat the GPIO as being open source and defer driving + it to when the restart is initiated. If this optional property is not + specified, the GPIO is initialized as an output in its inactive state. +- priority : A priority ranging from 0 to 255 (default 128) according to + the following guidelines: + 0: Restart handler of last resort, with limited restart + capabilities + 128: Default restart handler; use if no other restart handler is + expected to be available, and/or if restart functionality is + sufficient to restart the entire system + 255: Highest priority restart handler, will preempt all other + restart handlers +- active-delay: Delay (default 100) to wait after driving gpio active [ms] +- inactive-delay: Delay (default 100) to wait after driving gpio inactive [ms] +- wait-delay: Delay (default 3000) to wait after completing restart + sequence [ms] + +Examples: + +gpio-restart { + compatible = "gpio-restart"; + gpios = <&gpio 4 0>; + priority = <128>; + active-delay = <100>; + inactive-delay = <100>; + wait-delay = <3000>; +}; diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig index 88603b6990ed..a178e9c50a20 100644 --- a/drivers/power/reset/Kconfig +++ b/drivers/power/reset/Kconfig @@ -39,6 +39,14 @@ config POWER_RESET_GPIO 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 && POWER_RESET + 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. + config POWER_RESET_HISI bool "Hisilicon power-off driver" depends on POWER_RESET && ARCH_HISI diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile index 06f106b6cfc8..ab8cd348a099 100644 --- a/drivers/power/reset/Makefile +++ b/drivers/power/reset/Makefile @@ -2,6 +2,7 @@ obj-$(CONFIG_POWER_RESET_AS3722) += as3722-poweroff.o obj-$(CONFIG_POWER_RESET_AXXIA) += axxia-reset.o obj-$(CONFIG_POWER_RESET_BRCMSTB) += brcmstb-reboot.o obj-$(CONFIG_POWER_RESET_GPIO) += gpio-poweroff.o +obj-$(CONFIG_POWER_RESET_GPIO_RESTART) += gpio-restart.o obj-$(CONFIG_POWER_RESET_HISI) += hisi-reboot.o obj-$(CONFIG_POWER_RESET_MSM) += msm-poweroff.o obj-$(CONFIG_POWER_RESET_LTC2952) += ltc2952-poweroff.o diff --git a/drivers/power/reset/gpio-restart.c b/drivers/power/reset/gpio-restart.c new file mode 100644 index 000000000000..a76829b3f1cd --- /dev/null +++ b/drivers/power/reset/gpio-restart.c @@ -0,0 +1,149 @@ +/* + * Toggles a GPIO pin to restart a device + * + * Copyright (C) 2014 Google, Inc. + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * Based on the gpio-poweroff driver. + */ +#include <linux/reboot.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/delay.h> +#include <linux/platform_device.h> +#include <linux/gpio/consumer.h> +#include <linux/of_platform.h> +#include <linux/module.h> + +struct gpio_restart { + struct gpio_desc *reset_gpio; + struct notifier_block restart_handler; + u32 active_delay_ms; + u32 inactive_delay_ms; + u32 wait_delay_ms; +}; + +static int gpio_restart_notify(struct notifier_block *this, + unsigned long mode, void *cmd) +{ + struct gpio_restart *gpio_restart = + container_of(this, struct gpio_restart, restart_handler); + + /* drive it active, also inactive->active edge */ + gpiod_direction_output(gpio_restart->reset_gpio, 1); + mdelay(gpio_restart->active_delay_ms); + + /* drive inactive, also active->inactive edge */ + gpiod_set_value(gpio_restart->reset_gpio, 0); + mdelay(gpio_restart->inactive_delay_ms); + + /* drive it active, also inactive->active edge */ + gpiod_set_value(gpio_restart->reset_gpio, 1); + + /* give it some time */ + mdelay(gpio_restart->wait_delay_ms); + + WARN_ON(1); + + return NOTIFY_DONE; +} + +static int gpio_restart_probe(struct platform_device *pdev) +{ + struct gpio_restart *gpio_restart; + bool open_source = false; + u32 property; + int ret; + + gpio_restart = devm_kzalloc(&pdev->dev, sizeof(*gpio_restart), + GFP_KERNEL); + if (!gpio_restart) + return -ENOMEM; + + open_source = of_property_read_bool(pdev->dev.of_node, "open-source"); + + gpio_restart->reset_gpio = devm_gpiod_get(&pdev->dev, NULL, + open_source ? GPIOD_IN : GPIOD_OUT_LOW); + if (IS_ERR(gpio_restart->reset_gpio)) { + dev_err(&pdev->dev, "Could net get reset GPIO\n"); + return PTR_ERR(gpio_restart->reset_gpio); + } + + gpio_restart->restart_handler.notifier_call = gpio_restart_notify; + gpio_restart->restart_handler.priority = 128; + gpio_restart->active_delay_ms = 100; + gpio_restart->inactive_delay_ms = 100; + gpio_restart->wait_delay_ms = 3000; + + ret = of_property_read_u32(pdev->dev.of_node, "priority", &property); + if (!ret) { + if (property > 255) + dev_err(&pdev->dev, "Invalid priority property: %u\n", + property); + else + gpio_restart->restart_handler.priority = property; + } + + of_property_read_u32(pdev->dev.of_node, "active-delay", + &gpio_restart->active_delay_ms); + of_property_read_u32(pdev->dev.of_node, "inactive-delay", + &gpio_restart->inactive_delay_ms); + of_property_read_u32(pdev->dev.of_node, "wait-delay", + &gpio_restart->wait_delay_ms); + + platform_set_drvdata(pdev, gpio_restart); + + ret = register_restart_handler(&gpio_restart->restart_handler); + if (ret) { + dev_err(&pdev->dev, "%s: cannot register restart handler, %d\n", + __func__, ret); + return -ENODEV; + } + + return 0; +} + +static int gpio_restart_remove(struct platform_device *pdev) +{ + struct gpio_restart *gpio_restart = platform_get_drvdata(pdev); + int ret; + + ret = unregister_restart_handler(&gpio_restart->restart_handler); + if (ret) { + dev_err(&pdev->dev, + "%s: cannot unregister restart handler, %d\n", + __func__, ret); + return -ENODEV; + } + + return 0; +} + +static const struct of_device_id of_gpio_restart_match[] = { + { .compatible = "gpio-restart", }, + {}, +}; + +static struct platform_driver gpio_restart_driver = { + .probe = gpio_restart_probe, + .remove = gpio_restart_remove, + .driver = { + .name = "restart-gpio", + .owner = THIS_MODULE, + .of_match_table = of_gpio_restart_match, + }, +}; + +module_platform_driver(gpio_restart_driver); + +MODULE_AUTHOR("David Riley <davidriley@chromium.org>"); +MODULE_DESCRIPTION("GPIO restart driver"); +MODULE_LICENSE("GPL"); |