Commit 96ff0f5c authored by Jamie Lentin's avatar Jamie Lentin Committed by Jason Cooper

power: Add simple poweroff-gpio driver

Given appropriate devicetree bindings, this driver registers a
pm_power_off function to set a GPIO line high/low to power down
your board.
Signed-off-by: default avatarJamie Lentin <jm@lentin.co.uk>
Signed-off-by: default avatarAndrew Lunn <andrew@lunn.ch>
Tested-by: default avatarSimon Baatz <gmbnomis@gmail.com>
Signed-off-by: default avatarJason Cooper <jason@lakedaemon.net>
parent f4a00139
GPIO line that should be set high/low to power off a device
Required properties:
- compatible : should be "gpio-poweroff".
- gpios : The GPIO to set high/low, see "gpios property" in
Documentation/devicetree/bindings/gpio/gpio.txt. If the pin should be
low to power down the board set it to "Active Low", otherwise set
gpio to "Active High".
Optional properties:
- input : Initially configure the GPIO line as an input. Only reconfigure
it to an output when the pm_power_off function is called. If this optional
property is not specified, the GPIO is initialized as an output in its
inactive state.
Examples:
gpio-poweroff {
compatible = "gpio-poweroff";
gpios = <&gpio 4 0>; /* GPIO 4 Active Low */
};
...@@ -335,6 +335,9 @@ config AB8500_BATTERY_THERM_ON_BATCTRL ...@@ -335,6 +335,9 @@ config AB8500_BATTERY_THERM_ON_BATCTRL
help help
Say Y to enable battery temperature measurements using Say Y to enable battery temperature measurements using
thermistor connected on BATCTRL ADC. thermistor connected on BATCTRL ADC.
source "drivers/power/reset/Kconfig"
endif # POWER_SUPPLY endif # POWER_SUPPLY
source "drivers/power/avs/Kconfig" source "drivers/power/avs/Kconfig"
...@@ -49,3 +49,4 @@ obj-$(CONFIG_CHARGER_MAX8997) += max8997_charger.o ...@@ -49,3 +49,4 @@ obj-$(CONFIG_CHARGER_MAX8997) += max8997_charger.o
obj-$(CONFIG_CHARGER_MAX8998) += max8998_charger.o obj-$(CONFIG_CHARGER_MAX8998) += max8998_charger.o
obj-$(CONFIG_POWER_AVS) += avs/ obj-$(CONFIG_POWER_AVS) += avs/
obj-$(CONFIG_CHARGER_SMB347) += smb347-charger.o obj-$(CONFIG_CHARGER_SMB347) += smb347-charger.o
obj-$(CONFIG_POWER_RESET) += reset/
menuconfig POWER_RESET
bool "Board level reset or power off"
help
Provides a number of drivers which either reset a complete board
or shut it down, by manipulating the main power supply on the board.
Say Y here to enable board reset and power off
config POWER_RESET_GPIO
bool "GPIO power-off driver"
depends on OF_GPIO && POWER_RESET
help
This driver supports turning off your board via a GPIO line.
If your board needs a GPIO high/low to power down, say Y and
create a binding in your devicetree.
obj-$(CONFIG_POWER_RESET_GPIO) += gpio-poweroff.o
/*
* 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.h>
#include <linux/of_platform.h>
#include <linux/of_gpio.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 int gpio_num = -1;
static int gpio_active_low;
static void gpio_poweroff_do_poweroff(void)
{
BUG_ON(gpio_num == -1);
/* drive it active */
gpio_direction_output(gpio_num, !gpio_active_low);
mdelay(100);
/* rising edge or drive inactive */
gpio_set_value(gpio_num, gpio_active_low);
mdelay(100);
/* falling edge */
gpio_set_value(gpio_num, !gpio_active_low);
/* give it some time */
mdelay(3000);
WARN_ON(1);
}
static int __devinit gpio_poweroff_probe(struct platform_device *pdev)
{
enum of_gpio_flags flags;
bool input = false;
int ret;
/* If a pm_power_off function has already been added, leave it alone */
if (pm_power_off != NULL) {
pr_err("%s: pm_power_off function already registered",
__func__);
return -EBUSY;
}
gpio_num = of_get_gpio_flags(pdev->dev.of_node, 0, &flags);
if (gpio_num < 0) {
pr_err("%s: Could not get GPIO configuration: %d",
__func__, gpio_num);
return -ENODEV;
}
gpio_active_low = flags & OF_GPIO_ACTIVE_LOW;
if (of_get_property(pdev->dev.of_node, "input", NULL))
input = true;
ret = gpio_request(gpio_num, "poweroff-gpio");
if (ret) {
pr_err("%s: Could not get GPIO %d", __func__, gpio_num);
return ret;
}
if (input) {
if (gpio_direction_input(gpio_num)) {
pr_err("Could not set direction of GPIO %d to input",
gpio_num);
goto err;
}
} else {
if (gpio_direction_output(gpio_num, gpio_active_low)) {
pr_err("Could not set direction of GPIO %d", gpio_num);
goto err;
}
}
pm_power_off = &gpio_poweroff_do_poweroff;
return 0;
err:
gpio_free(gpio_num);
return -ENODEV;
}
static int __devexit gpio_poweroff_remove(struct platform_device *pdev)
{
if (gpio_num != -1)
gpio_free(gpio_num);
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 = __devexit_p(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");
MODULE_ALIAS("platform:poweroff-gpio");
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