diff options
Diffstat (limited to 'drivers/power/reset/gpio-restart.c')
| -rw-r--r-- | drivers/power/reset/gpio-restart.c | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/drivers/power/reset/gpio-restart.c b/drivers/power/reset/gpio-restart.c new file mode 100644 index 0000000000..ed2748f910 --- /dev/null +++ b/drivers/power/reset/gpio-restart.c @@ -0,0 +1,97 @@ +// 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 <linux/gpio/consumer.h> + +struct gpio_restart { + struct gpio_desc *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 */ + gpiod_direction_output(gpio_restart->reset_gpio, true); + mdelay(gpio_restart->active_delay_ms); + + /* drive inactive, also active->inactive edge */ + gpiod_direction_output(gpio_restart->reset_gpio, false); + mdelay(gpio_restart->inactive_delay_ms); + + /* drive it active, also inactive->active edge */ + gpiod_direction_output(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 *dev) +{ + struct device_node *np = dev->of_node; + struct gpio_restart *gpio_restart; + struct gpio_desc *gpiod; + bool open_source = false; + u32 property; + int ret; + + gpio_restart = xzalloc(sizeof(*gpio_restart)); + + open_source = of_property_read_bool(np, "open-source"); + + gpiod = gpiod_get(dev, NULL, open_source ? GPIOD_IN : GPIOD_OUT_LOW); + if (IS_ERR(gpiod)) + return dev_errp_probe(dev, gpiod, "Could not get reset GPIO\n"); + + gpio_restart->reset_gpio = gpiod; + 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->of_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", }, + {}, +}; +MODULE_DEVICE_TABLE(of, of_gpio_restart_match); + +static struct driver 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@chromium.org>"); +MODULE_DESCRIPTION("GPIO restart driver"); +MODULE_LICENSE("GPL"); |