alistair23-linux/drivers/power/reset/gpio-poweroff.c
Linus Torvalds 974b33586b ARM: arm-soc fixes for 3.8-rc
People are back from the holiday breaks, and it shows. Here are a bunch of
 fixes for a number of platforms:
  - A couple of small fixes for Nomadik
  - A larger set of changes for kirkwood/mvebu
    - uart driver selection, dt clocks, gpio-poweroff fixups,
      a few __init annotation fixes and some error handling improvement
      in their xor dma driver.
  - i.MX had a couple of minor fixes (and a critical one for flexcan2
    clock setup)
  - MXS has a small board fix and a framebuffer bugfix
  - A set of fixes for Samsung Exynos, fixing default bootargs and some
    Exynos5440 clock issues
  - A set of OMAP changes including PM fixes and a few sparse warning
    fixups
 
 All in all a bit more positive code delta than we'd ideally want to see
 here, mostly from the OMAP PM changes, but nothing overly crazy.
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Merge tag 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc

Pull ARM SoC fixes from Olof Johansson:
 "People are back from the holiday breaks, and it shows.  Here are a
  bunch of fixes for a number of platforms:
   - A couple of small fixes for Nomadik
   - A larger set of changes for kirkwood/mvebu
     - uart driver selection, dt clocks, gpio-poweroff fixups, a few
       __init annotation fixes and some error handling improvement in
       their xor dma driver.
   - i.MX had a couple of minor fixes (and a critical one for flexcan2
     clock setup)
   - MXS has a small board fix and a framebuffer bugfix
   - A set of fixes for Samsung Exynos, fixing default bootargs and some
     Exynos5440 clock issues
   - A set of OMAP changes including PM fixes and a few sparse warning
     fixups

  All in all a bit more positive code delta than we'd ideally want to
  see here, mostly from the OMAP PM changes, but nothing overly crazy."

* tag 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (44 commits)
  ARM: clps711x: Fix bad merge of clockevents setup
  ARM: highbank: save and restore L2 cache and GIC on suspend
  ARM: highbank: add a power request clear
  ARM: highbank: fix secondary boot and hotplug
  ARM: highbank: fix typos with hignbank in power request functions
  ARM: dts: fix highbank cpu mpidr values
  ARM: dts: add device_type prop to cpu nodes on Calxeda platforms
  ARM: mx5: Fix MX53 flexcan2 clock
  ARM: OMAP2+: am33xx-hwmod: Fix wrongly terminated am33xx_usbss_mpu_irqs array
  pinctrl: mvebu: make pdma clock on dove mandatory
  ARM: Dove: Add pinctrl clock to DT
  dma: mv_xor: fix error handling for clocks
  dma: mv_xor: fix error handling of mv_xor_channel_add()
  arm: mvebu: Add missing ; for cpu node.
  arm: mvebu: Armada XP MV78230 has only three Ethernet interfaces
  arm: mvebu: Armada XP MV78230 has two cores, not one
  clk: mvebu: Remove inappropriate __init tagging
  ARM: Kirkwood: Use fixed-regulator instead of board gpio call
  ARM: Kirkwood: Fix missing sdio clock
  ARM: Kirkwood: Switch TWSI1 of 88f6282 to DT clock providers
  ...
2013-01-08 18:53:56 -08:00

127 lines
2.9 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.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_is_valid(gpio_num));
/* drive it active, also inactive->active edge */
gpio_direction_output(gpio_num, !gpio_active_low);
mdelay(100);
/* drive inactive, also active->inactive edge */
gpio_set_value(gpio_num, gpio_active_low);
mdelay(100);
/* drive it active, also inactive->active edge */
gpio_set_value(gpio_num, !gpio_active_low);
/* give it some time */
mdelay(3000);
WARN_ON(1);
}
static int 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_is_valid(gpio_num))
return gpio_num;
gpio_active_low = flags & OF_GPIO_ACTIVE_LOW;
input = of_property_read_bool(pdev->dev.of_node, "input");
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 gpio_poweroff_remove(struct platform_device *pdev)
{
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 = 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");