arm ubuntu 按键关机的实现
在arm ubuntu系统上，关机操作 可以用命令实现： poweroff 或者 shutdown，但是如果没有终端设备或者键盘，就无法使用命令行了，这里使用acpi机制，acpi监听power事件，来操作系统。
实现步骤：
1、驱动部分，首先要实现gpio-keys设备中，power键指定，就是用一个中断引脚，code类型定义为”KEY_POWER“
比如：
/* GPIO KEYS */
static struct gpio_keys_button smdk4412_button[] = {
{
<span style="color:#ff0000;">.code = KEY_POWER,</span>
.gpio = EXYNOS4_GPX0(1),
.desc = "gpio-keys: KEY_POWER",
.type = EV_KEY,
.active_low = 1,
.debounce_interval = 1,
.wakeup = 1,
}, {
.code = KEY_VOLUMEUP,//.code = KEY_LEFT,
.gpio = EXYNOS4_GPX1(0),
.desc = "gpio-keys: KEY_VOLUMEUP",
.type = EV_KEY,
.active_low = 1,
.debounce_interval = 10,
}, {
.code = KEY_VOLUMEDOWN,//.code = KEY_DOWN,
.gpio = EXYNOS4_GPX1(1),
.desc = "gpio-keys: KEY_VOLUMEDOWN",
.type = EV_KEY,
.active_low = 1,
.debounce_interval = 10,
},
};
static struct gpio_keys_platform_data smdk4x12_gpio_keys_data = {
.buttons = smdk4412_button,
.nbuttons = ARRAY_SIZE(smdk4412_button),
.rep = 1,
.poll_interval = 100,
};
static struct platform_device smdk4x12_gpio_keys = {
.name = "gpio-keys",
.dev = {
.platform_data = &smdk4x12_gpio_keys_data,
},
};红色标记 .code=KEY_POWER, 就是电源键的事件类型，使用GPX0_1作为中断源来触发；下面两个是音量键的事件类型，可以实现音量的大小调节，
驱动配置好以后，可以在系统中使用 cat /proc/interrupts 来检查按键触发是否正常
417: 50 0 0 0 exynos-eint gpio-keys: KEY_POWER经过检测，我的板子，中断没有问题^^.
2、驱动做好后，就可以安装acpi了，
运行命令：
sudo apt-get update
sudo apt-get install acpid
备份/etc/acpi/powerbtn.sh
cp /etc/acpi/powerbtn.sh /etc/acpi/powerbtn.sh_bk
修改/etc/acpi/powerbtn.sh
只保留下面的部分
#!/bin/sh # /etc/acpi/powerbtn.sh # Initiates a shutdown when the power button has been # pressed. /sbin/shutdown -h now "Power button pressed"
重启apcid服务
service acpid stop service acpid start
3、按下power键，试一下吧
Broadcast message from root@yunz
(unknown) at 20:20 ...
The system is going down for halt NOW!
Power button pressed
wait-for-state stop/waiting
* Stopping rsync daemon rsync [ OK ]
* Stopping NTP server ntpd [ OK ]
* Asking all remaining processes to terminate... [ OK ]
* All processes ended within 1 seconds... [ OK ]
ModemManager[667]: <warn> Could not acquire the 'org.freedesktop.ModemManager1' service name
ModemManager[667]: <info> ModemManager is shut down
* Unmounting temporary filesystems... [ OK ]
* Deactivating swap... [ OK ]
* Unmounting local filesystems... [ OK ]
* Will now halt
[ 37.468376] exynos4-reboot: Notifier called
[ 38.132085] Power down.
[ 38.1330▒OK