1/* 2 * arch/arm/mach-ixp4xx/dsmg600-power.c 3 * 4 * DSM-G600 Power/Reset driver 5 * Author: Michael Westerhof <mwester@dls.net> 6 * 7 * Based on nslu2-power.c 8 * Copyright (C) 2005 Tower Technologies 9 * Author: Alessandro Zummo <a.zummo@towertech.it> 10 * 11 * which was based on nslu2-io.c 12 * Copyright (C) 2004 Karen Spearel 13 * 14 * Maintainers: http://www.nslu2-linux.org/ 15 * 16 * This program is free software; you can redistribute it and/or modify 17 * it under the terms of the GNU General Public License version 2 as 18 * published by the Free Software Foundation. 19 * 20 */ 21 22#include <linux/module.h> 23#include <linux/reboot.h> 24#include <linux/interrupt.h> 25#include <linux/irq.h> 26#include <linux/jiffies.h> 27#include <linux/timer.h> 28 29#include <asm/mach-types.h> 30 31extern void ctrl_alt_del(void); 32 33/* This is used to make sure the power-button pusher is serious. The button 34 * must be held until the value of this counter reaches zero. 35 */ 36static volatile int power_button_countdown; 37 38/* Must hold the button down for at least this many counts to be processed */ 39#define PBUTTON_HOLDDOWN_COUNT 4 /* 2 secs */ 40 41static void dsmg600_power_handler(unsigned long data); 42static DEFINE_TIMER(dsmg600_power_timer, dsmg600_power_handler, 0, 0); 43 44static void dsmg600_power_handler(unsigned long data) 45{ 46 /* This routine is called twice per second to check the 47 * state of the power button. 48 */ 49 50 if (*IXP4XX_GPIO_GPINR & DSMG600_PB_BM) { 51 52 /* IO Pin is 1 (button pushed) */ 53 if (power_button_countdown == 0) { 54 /* Signal init to do the ctrlaltdel action, this will bypass 55 * init if it hasn't started and do a kernel_restart. 56 */ 57 ctrl_alt_del(); 58 59 /* Change the state of the power LED to "blink" */ 60 gpio_line_set(DSMG600_LED_PWR_GPIO, IXP4XX_GPIO_LOW); 61 } 62 power_button_countdown--; 63 64 } else { 65 power_button_countdown = PBUTTON_HOLDDOWN_COUNT; 66 } 67 68 mod_timer(&dsmg600_power_timer, jiffies + msecs_to_jiffies(500)); 69} 70 71static irqreturn_t dsmg600_reset_handler(int irq, void *dev_id) 72{ 73 /* This is the paper-clip reset, it shuts the machine down directly. */ 74 machine_power_off(); 75 76 return IRQ_HANDLED; 77} 78 79static int __init dsmg600_power_init(void) 80{ 81 if (!(machine_is_dsmg600())) 82 return 0; 83 84 if (request_irq(DSMG600_RB_IRQ, &dsmg600_reset_handler, 85 IRQF_DISABLED | IRQF_TRIGGER_LOW, "DSM-G600 reset button", 86 NULL) < 0) { 87 88 printk(KERN_DEBUG "Reset Button IRQ %d not available\n", 89 DSMG600_RB_IRQ); 90 91 return -EIO; 92 } 93 94 /* The power button on the D-Link DSM-G600 is on GPIO 15, but 95 * it cannot handle interrupts on that GPIO line. So we'll 96 * have to poll it with a kernel timer. 97 */ 98 99 /* Make sure that the power button GPIO is set up as an input */ 100 gpio_line_config(DSMG600_PB_GPIO, IXP4XX_GPIO_IN); 101 102 /* Set the initial value for the power button IRQ handler */ 103 power_button_countdown = PBUTTON_HOLDDOWN_COUNT; 104 105 mod_timer(&dsmg600_power_timer, jiffies + msecs_to_jiffies(500)); 106 107 return 0; 108} 109 110static void __exit dsmg600_power_exit(void) 111{ 112 if (!(machine_is_dsmg600())) 113 return; 114 115 del_timer_sync(&dsmg600_power_timer); 116 117 free_irq(DSMG600_RB_IRQ, NULL); 118} 119 120module_init(dsmg600_power_init); 121module_exit(dsmg600_power_exit); 122 123MODULE_AUTHOR("Michael Westerhof <mwester@dls.net>"); 124MODULE_DESCRIPTION("DSM-G600 Power/Reset driver"); 125MODULE_LICENSE("GPL"); 126