mirror of
https://github.com/torvalds/linux.git
synced 2024-11-17 09:31:50 +00:00
86336ba4b7
This switches the GPIO poweroff driver to use GPIO descriptors rather than numeral GPIOs. We get rid of the specific inversion handling as GPIO descriptors know if they are active low or high and can assert the line properly, so we do not need to check the flag OF_GPIO_ACTIVE_LOW returned from the old call of_get_gpio_flags() anymore. Also convert to use managed resources and use dev_* message printing while we're at it. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Sebastian Reichel <sre@kernel.org>
113 lines
2.6 KiB
C
113 lines
2.6 KiB
C
/*
|
|
* Toggles a GPIO pin to power down a device
|
|
*
|
|
* Jamie Lentin <jm@lentin.co.uk>
|
|
* Andrew Lunn <andrew@lunn.ch>
|
|
*
|
|
* Copyright (C) 2012 Jamie Lentin
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
*/
|
|
#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>
|
|
|
|
/*
|
|
* Hold configuration here, cannot be more than one instance of the driver
|
|
* since pm_power_off itself is global.
|
|
*/
|
|
static struct gpio_desc *reset_gpio;
|
|
|
|
static void gpio_poweroff_do_poweroff(void)
|
|
{
|
|
BUG_ON(!reset_gpio);
|
|
|
|
/* drive it active, also inactive->active edge */
|
|
gpiod_direction_output(reset_gpio, 1);
|
|
mdelay(100);
|
|
/* drive inactive, also active->inactive edge */
|
|
gpiod_set_value(reset_gpio, 0);
|
|
mdelay(100);
|
|
|
|
/* drive it active, also inactive->active edge */
|
|
gpiod_set_value(reset_gpio, 1);
|
|
|
|
/* give it some time */
|
|
mdelay(3000);
|
|
|
|
WARN_ON(1);
|
|
}
|
|
|
|
static int gpio_poweroff_probe(struct platform_device *pdev)
|
|
{
|
|
bool input = false;
|
|
|
|
/* 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",
|
|
__func__);
|
|
return -EBUSY;
|
|
}
|
|
|
|
reset_gpio = devm_gpiod_get(&pdev->dev, NULL);
|
|
if (IS_ERR(reset_gpio))
|
|
return PTR_ERR(reset_gpio);
|
|
|
|
input = of_property_read_bool(pdev->dev.of_node, "input");
|
|
|
|
if (input) {
|
|
if (gpiod_direction_input(reset_gpio)) {
|
|
dev_err(&pdev->dev,
|
|
"Could not set direction of reset GPIO to input\n");
|
|
return -ENODEV;
|
|
}
|
|
} else {
|
|
if (gpiod_direction_output(reset_gpio, 0)) {
|
|
dev_err(&pdev->dev,
|
|
"Could not set direction of reset GPIO\n");
|
|
return -ENODEV;
|
|
}
|
|
}
|
|
|
|
pm_power_off = &gpio_poweroff_do_poweroff;
|
|
return 0;
|
|
}
|
|
|
|
static int gpio_poweroff_remove(struct platform_device *pdev)
|
|
{
|
|
if (pm_power_off == &gpio_poweroff_do_poweroff)
|
|
pm_power_off = NULL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct of_device_id of_gpio_poweroff_match[] = {
|
|
{ .compatible = "gpio-poweroff", },
|
|
{},
|
|
};
|
|
|
|
static struct platform_driver gpio_poweroff_driver = {
|
|
.probe = gpio_poweroff_probe,
|
|
.remove = gpio_poweroff_remove,
|
|
.driver = {
|
|
.name = "poweroff-gpio",
|
|
.owner = THIS_MODULE,
|
|
.of_match_table = of_gpio_poweroff_match,
|
|
},
|
|
};
|
|
|
|
module_platform_driver(gpio_poweroff_driver);
|
|
|
|
MODULE_AUTHOR("Jamie Lentin <jm@lentin.co.uk>");
|
|
MODULE_DESCRIPTION("GPIO poweroff driver");
|
|
MODULE_LICENSE("GPL v2");
|
|
MODULE_ALIAS("platform:poweroff-gpio");
|