![Wolfram Sang](/assets/img/avatar_default.png)
A platform_driver does not need to set an owner, it will be populated by the driver core. Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
149 lines
4 KiB
C
149 lines
4 KiB
C
/*
|
|
* 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",
|
|
.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");
|