input子系统gpio_keys.c --- mini2440

操作环境：
开发板：mini2440
CPU：（samsung）s3c2440
Linux版本：Linux-2.6.32.2

需要在linux内核配置里选上相关的配置。在内核源码目录下：

make menuconfig ARCH=arm CROSS_COMPILE=arm-linux-

    Device Drivers --->
        Input device support --->
            [*] Keyboards --->
                <*> GPIO Buttons

gpio_keys.h

#ifndef _GPIO_KEYS_H
#define _GPIO_KEYS_H

struct gpio_keys_button {
    /* Configuration parameters */
    int code;        /* input event code (KEY_*, SW_*) */
    int gpio;
    int active_low;
    char *desc;
    int type;        /* input event type (EV_KEY, EV_SW) */
    int wakeup;        /* configure the button as a wake-up source */
    int debounce_interval;    /* debounce ticks interval in msecs */
};


struct gpio_keys_platform_data {
    struct gpio_keys_button *buttons;
    int nbuttons;
    unsigned int rep:1;        /* enable input subsystem auto repeat */

    const char *name; /* input device name */

};

#endif

mach-mini2440.c  中添加

#include
#include
#include
#include
#include

/* gpio-keys */

static struct gpio_keys_button s3c2440_gpio_keys_button[]=
{
    {KEY_1, S3C2410_GPG(0), 1, "mygpio-key1", EV_KEY, 0, 100},
    {KEY_2, S3C2410_GPG(3), 1, "mygpio-key2", EV_KEY, 0, 100},
    {KEY_3, S3C2410_GPG(5), 1, "mygpio-key3", EV_KEY, 0, 100},
    {KEY_4, S3C2410_GPG(6), 1, "mygpio-key4", EV_KEY, 0, 100},
    {KEY_5, S3C2410_GPG(7), 1, "mygpio-key5", EV_KEY, 0, 100},
    {KEY_6, S3C2410_GPG(11), 1, "mygpio-key6", EV_KEY, 0, 100},
};

static struct gpio_keys_platform_data s3c2440_gpio_keys_data=
{
    .buttons=s3c2440_gpio_keys_button,
    .nbuttons=ARRAY_SIZE(s3c2440_gpio_keys_button),
    .rep = 1,
    .name = "mygpio-keys",
};

static struct platform_device s3c2440_gpio_keys = {
        .name = "gpio-keys",
        .dev = {
            .platform_data = &s3c2440_gpio_keys_data,
           },

};

/* devices we initialise */

static struct platform_device *mini2440_devices[] __initdata = {
 &s3c_device_usb,
 &s3c_device_rtc,
 &s3c_device_lcd,
 &s3c_device_wdt,
 &s3c_device_i2c0,
 &s3c_device_iis,
 &mini2440_device_eth,
 &s3c24xx_uda134x,
 &s3c_device_nand,
 &s3c_device_sdi,
 &s3c_device_usbgadget,
 &s3c2440_gpio_keys,//only add this
};

重新编译内核并移植

使用hexdump命令，可以查看二进制数据。

struct input_event {
    struct timeval time;    //事件发生的时间(占据8字节)
    __u16 type;            //事件类型(占据2字节，比如按键类型事件，EV_KEY是1)
    __u16 code;            //事件的具体类型(占据2字节，比如按键L和S他们代表的十六进制数值)
    __s32 value;        //值(例如松开还是按下(占据4字节，1表示按下，0表示松开))
};