Linux系统编程应用 Linux输入子系统(二）

Posted 2022-03-11 itcast0

​1. 设备ID信息结构体​

结构体如下：

/*
 * IOCTLs (0x00 - 0x7f)
 */

struct input_id 
    __u16 bustype;
    __u16 vendor;
    __u16 product;
    __u16 version;
;

struct input_absinfo 
    __s32 value;
    __s32 minimum;
    __s32 maximum;
    __s32 fuzz;
    __s32 flat;
;

​2. 相关ioctl操作​

#define EVIOCGVERSION       _IOR(E, 0x01, int)            /* get driver version */
#define EVIOCGID        _IOR(E, 0x02, struct input_id)    /* get device ID */
#define EVIOCGREP       _IOR(E, 0x03, int[2])         /* get repeat settings */
#define EVIOCSREP       _IOW(E, 0x03, int[2])         /* set repeat settings */
#define EVIOCGKEYCODE       _IOR(E, 0x04, int[2])         /* get keycode */
#define EVIOCSKEYCODE       _IOW(E, 0x04, int[2])         /* set keycode */

#define EVIOCGNAME(len)     _IOC(_IOC_READ, E, 0x06, len)     /* get device name */
#define EVIOCGPHYS(len)     _IOC(_IOC_READ, E, 0x07, len)     /* get physical location */
#define EVIOCGUNIQ(len)     _IOC(_IOC_READ, E, 0x08, len)     /* get unique identifier */

#define EVIOCGKEY(len)      _IOC(_IOC_READ, E, 0x18, len)     /* get global keystate */
#define EVIOCGLED(len)      _IOC(_IOC_READ, E, 0x19, len)     /* get all LEDs */
#define EVIOCGSND(len)      _IOC(_IOC_READ, E, 0x1a, len)     /* get all sounds status */
#define EVIOCGSW(len)       _IOC(_IOC_READ, E, 0x1b, len)     /* get all switch states */

#define EVIOCGBIT(ev,len)   _IOC(_IOC_READ, E, 0x20 + ev, len)    /* get event bits */
#define EVIOCGABS(abs)      _IOR(E, 0x40 + abs, struct input_absinfo)     /* get abs value/limits */
#define EVIOCSABS(abs)      _IOW(E, 0xc0 + abs, struct input_absinfo)     /* set abs value/limits */

#define EVIOCSFF        _IOC(_IOC_WRITE, E, 0x80, sizeof(struct ff_effect))   /* send a force effect to a force feedback device */
#define EVIOCRMFF       _IOW(E, 0x81, int)            /* Erase a force effect */
#define EVIOCGEFFECTS       _IOR(E, 0x84, int)            /* Report number of effects playable at the same time */

#define EVIOCGRAB       _IOW(E, 0x90, int)            /* Grab/Release device */

​3. 相关ID值​

/*
 * IDs.
 */

#define ID_BUS          0
#define ID_VENDOR       1
#define ID_PRODUCT      2
#define ID_VERSION      3

#define BUS_PCI         0x01
#define BUS_ISAPNP      0x02
#define BUS_USB         0x03
#define BUS_HIL         0x04
#define BUS_BLUETOOTH       0x05

#define BUS_ISA         0x10
#define BUS_I8042       0x11
#define BUS_XTKBD       0x12
#define BUS_RS232       0x13
#define BUS_GAMEPORT        0x14
#define BUS_PARPORT     0x15
#define BUS_AMIGA       0x16
#define BUS_ADB         0x17
#define BUS_I2C         0x18
#define BUS_HOST        0x19
#define BUS_GSC         0x1A

​4. 相关ioctl操作示例​

参考代码：

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <linux/input.h>

#define SIZE 128

int main(void)

    int ret = -1;
    int fd = -1;
    int value;
    int repeat[2];

    struct input_id id;
    char name[SIZE];

    fd = open("/dev/input/event0", O_RDONLY);
    if (-1 == fd)
    
        perror("open"); 
        goto err0;
    

    //get driver version
    value = 0;
    ret = ioctl(fd, EVIOCGVERSION, &value);
    if (-1 == ret)
    
        perror("ioctl"); 
        goto err0;
    
    printf("version: %d\\n", value);

    //get device ID
    memset(&id, 0, sizeof(id));
    ret = ioctl(fd, EVIOCGID, &id);
    if (-1 == ret)
    
        perror("ioctl"); 
        goto err0;
    
    printf("bustype: %hu vendor: %hu product: %hu version: %hu\\n", id.bustype, id.vendor, id.product, id.version);

    //get or set repead 
    memset(repeat, 0, sizeof(repeat)); 
    ret = ioctl(fd, EVIOCGREP, repeat);
    if (-1 == ret)
    
        perror("ioctl"); 
        goto err0;
    
    printf("repeat[0]: %d repeat[1]: %d\\n", repeat[0], repeat[1]);

    //get device name
    ret = ioctl(fd, EVIOCGNAME(SIZE), name);
    if (-1 == ret)
    
        perror("ioctl"); 
        goto err0;
    
    printf("name: %s\\n", name);

    //get physical location
    memset(name, 0, SIZE);
    ret = ioctl(fd, EVIOCGPHYS(SIZE), name);
    if (-1 == ret)
    
        perror("ioctl"); 
        goto err0;
    
    printf("physical location: %s\\n", name);

    //get unique identifier
    memset(name, 0, SIZE);
    ret = ioctl(fd, EVIOCGUNIQ(SIZE), name);
    if (-1 == ret)
    
        perror("ioctl"); 
        goto err0;
    
    printf("unique identifier: %s\\n", name);


    close(fd);

    return 0;
err0:
    return -1;

执行结果：