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/*
* arch/arm/mach-ixp4xx/dsmg600-power.c
*
* DSM-G600 Power/Reset driver
* Author: Michael Westerhof <mwester@dls.net>
*
* Based on nslu2-power.c
* Copyright (C) 2005 Tower Technologies
* Author: Alessandro Zummo <a.zummo@towertech.it>
*
* which was based on nslu2-io.c
* Copyright (C) 2004 Karen Spearel
*
* Maintainers: http://www.nslu2-linux.org/
*
* 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/module.h>
#include <linux/reboot.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/jiffies.h>
#include <linux/timer.h>
#include <asm/gpio.h>
#include <asm/mach-types.h>
/* This is used to make sure the power-button pusher is serious. The button
* must be held until the value of this counter reaches zero.
*/
static int power_button_countdown;
/* Must hold the button down for at least this many counts to be processed */
#define PBUTTON_HOLDDOWN_COUNT 4 /* 2 secs */
static void dsmg600_power_handler(unsigned long data);
static DEFINE_TIMER(dsmg600_power_timer, dsmg600_power_handler, 0, 0);
static void dsmg600_power_handler(unsigned long data)
{
/* This routine is called twice per second to check the
* state of the power button.
*/
if (gpio_get_value(DSMG600_PB_GPIO)) {
/* IO Pin is 1 (button pushed) */
if (power_button_countdown > 0)
power_button_countdown--;
} else {
/* Done on button release, to allow for auto-power-on mods. */
if (power_button_countdown == 0) {
/* Signal init to do the ctrlaltdel action,
* this will bypass init if it hasn't started
* and do a kernel_restart.
*/
ctrl_alt_del();
/* Change the state of the power LED to "blink" */
gpio_line_set(DSMG600_LED_PWR_GPIO, IXP4XX_GPIO_LOW);
} else {
power_button_countdown = PBUTTON_HOLDDOWN_COUNT;
}
}
mod_timer(&dsmg600_power_timer, jiffies + msecs_to_jiffies(500));
}
static irqreturn_t dsmg600_reset_handler(int irq, void *dev_id)
{
/* This is the paper-clip reset, it shuts the machine down directly. */
machine_power_off();
return IRQ_HANDLED;
}
static int __init dsmg600_power_init(void)
{
if (!(machine_is_dsmg600()))
return 0;
if (request_irq(gpio_to_irq(DSMG600_RB_GPIO), &dsmg600_reset_handler,
IRQF_DISABLED | IRQF_TRIGGER_LOW, "DSM-G600 reset button",
NULL) < 0) {
printk(KERN_DEBUG "Reset Button IRQ %d not available\n",
gpio_to_irq(DSMG600_RB_GPIO));
return -EIO;
}
/* The power button on the D-Link DSM-G600 is on GPIO 15, but
* it cannot handle interrupts on that GPIO line. So we'll
* have to poll it with a kernel timer.
*/
/* Make sure that the power button GPIO is set up as an input */
gpio_line_config(DSMG600_PB_GPIO, IXP4XX_GPIO_IN);
/* Set the initial value for the power button IRQ handler */
power_button_countdown = PBUTTON_HOLDDOWN_COUNT;
mod_timer(&dsmg600_power_timer, jiffies + msecs_to_jiffies(500));
return 0;
}
static void __exit dsmg600_power_exit(void)
{
if (!(machine_is_dsmg600()))
return;
del_timer_sync(&dsmg600_power_timer);
free_irq(gpio_to_irq(DSMG600_RB_GPIO), NULL);
}
module_init(dsmg600_power_init);
module_exit(dsmg600_power_exit);
MODULE_AUTHOR("Michael Westerhof <mwester@dls.net>");
MODULE_DESCRIPTION("DSM-G600 Power/Reset driver");
MODULE_LICENSE("GPL");
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