读取linux input 的event 事件的 应用程序

 

重点参考：

 

   https://www.kernel.org/doc/Documentation/input/event-codes.txt

   http://blog.sina.com.cn/s/blog_4ad7c2540101cxa7.html 

   http://staratsky.iteye.com/blog/1734631

 

转自： http://blog.csdn.net/lanmanck/article/details/8423669

 

 

相信各位使用嵌入式的都希望直接读取键值，特别是芯片厂家已经提供input驱动的情况下，例如GPIO或者扫描类型的键盘。那么在应用层如何通过C语言获取键值呢？

给兄弟们一个重量级的源码，看下面，大家拿去编译运行就知道怎么回事了，当然，可以使用select而不是while()来读取更好一点，留给各位去想象了：

注意：

#include<linux/input.h>

为内核源码的头文件，注意路径，一般为kernel/include/linux/input.h

ev.c:

 

/*
 * Copyright 2002 Red Hat Inc., Durham, North Carolina.
 *
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation on the rights to use, copy, modify, merge,
 * publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial
 * portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NON-INFRINGEMENT.  IN NO EVENT SHALL RED HAT AND/OR THEIR SUPPLIERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 * This is a simple test program that reads from /dev/input/event*,
 * decoding events into a human readable form.
 */

/*
 * Authors:
 *   Rickard E. (Rik) Faith <[e-mail]>
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <fcntl.h>
#include <errno.h>
#include <time.h>
#include <linux/input.h>

struct input_event event;

int main(int argc, char **argv)
{
    char          name[64];           /* RATS: Use ok, but could be better */
    char          buf[256] = { 0, };  /* RATS: Use ok */
    unsigned char mask[EV_MAX/8 + 1]; /* RATS: Use ok */
    int           version;
    int           fd = 0;
    int           rc;
    int           i, j;
    char          *tmp;

#define test_bit(bit) (mask[(bit)/8] & (1 << ((bit)%8)))

    for (i = 0; i < 32; i++) {
        sprintf(name, "/dev/input/event%d", i);
        if ((fd = open(name, O_RDONLY, 0)) >= 0) {
            ioctl(fd, EVIOCGVERSION, &version);
            ioctl(fd, EVIOCGNAME(sizeof(buf)), buf);
            ioctl(fd, EVIOCGBIT(0, sizeof(mask)), mask);
            printf("%s\n", name);
            printf("    evdev version: %d.%d.%d\n",
                   version >> 16, (version >> 8) & 0xff, version & 0xff);
            printf("    name: %s\n", buf);
            printf("    features:");
            for (j = 0; j < EV_MAX; j++) {
                if (test_bit(j)) {
                    const char *type = "unknown";
                    switch(j) {
                    case EV_KEY: type = "keys/buttons"; break;
                    case EV_REL: type = "relative";     break;
                    case EV_ABS: type = "absolute";     break;
                    case EV_MSC: type = "reserved";     break;
                    case EV_LED: type = "leds";         break;
                    case EV_SND: type = "sound";        break;
                    case EV_REP: type = "repeat";       break;
                    case EV_FF:  type = "feedback";     break;
                    }
                    printf(" %s", type);
                }
            }
            printf("\n");
            close(fd);
        }
    }

    if (argc > 1) {
        sprintf(name, "/dev/input/event%d", atoi(argv[1]));
        if ((fd = open(name, O_RDWR, 0)) >= 0) {
            printf("%s: open, fd = %d\n", name, fd);
            for (i = 0; i < LED_MAX; i++) {
                event.time.tv_sec  = time(0);
                event.time.tv_usec = 0;
                event.type         = EV_LED;
                event.code         = i;
                event.value        = 0;
                write(fd, &event, sizeof(event));
            }

            while ((rc = read(fd, &event, sizeof(event))) > 0) {
                printf("%-24.24s.%06lu type 0x%04x; code 0x%04x;"
                       " value 0x%08x; ",
                       ctime(&event.time.tv_sec),
                       event.time.tv_usec,
                       event.type, event.code, event.value);
                switch (event.type) {
                case EV_KEY:
                    if (event.code > BTN_MISC) {
                        printf("Button %d %s",
                               event.code & 0xff,
                               event.value ? "press" : "release");
                    } else {
                        printf("Key %d (0x%x) %s",
                               event.code & 0xff,
                               event.code & 0xff,
                               event.value ? "press" : "release");
                    }
                    break;
                case EV_REL:
                    switch (event.code) {
                    case REL_X:      tmp = "X";       break;
                    case REL_Y:      tmp = "Y";       break;
                    case REL_HWHEEL: tmp = "HWHEEL";  break;
                    case REL_DIAL:   tmp = "DIAL";    break;
                    case REL_WHEEL:  tmp = "WHEEL";   break;
                    case REL_MISC:   tmp = "MISC";    break;
                    default:         tmp = "UNKNOWN"; break;
                    }
                    printf("Relative %s %d", tmp, event.value);
                    break;
                case EV_ABS:
                    switch (event.code) {
                    case ABS_X:        tmp = "X";        break;
                    case ABS_Y:        tmp = "Y";        break;
                    case ABS_Z:        tmp = "Z";        break;
                    case ABS_RX:       tmp = "RX";       break;
                    case ABS_RY:       tmp = "RY";       break;
                    case ABS_RZ:       tmp = "RZ";       break;
                    case ABS_THROTTLE: tmp = "THROTTLE"; break;
                    case ABS_RUDDER:   tmp = "RUDDER";   break;
                    case ABS_WHEEL:    tmp = "WHEEL";    break;
                    case ABS_GAS:      tmp = "GAS";      break;
                    case ABS_BRAKE:    tmp = "BRAKE";    break;
                    case ABS_HAT0X:    tmp = "HAT0X";    break;
                    case ABS_HAT0Y:    tmp = "HAT0Y";    break;
                    case ABS_HAT1X:    tmp = "HAT1X";    break;
                    case ABS_HAT1Y:    tmp = "HAT1Y";    break;
                    case ABS_HAT2X:    tmp = "HAT2X";    break;
                    case ABS_HAT2Y:    tmp = "HAT2Y";    break;
                    case ABS_HAT3X:    tmp = "HAT3X";    break;
                    case ABS_HAT3Y:    tmp = "HAT3Y";    break;
                    case ABS_PRESSURE: tmp = "PRESSURE"; break;
                    case ABS_DISTANCE: tmp = "DISTANCE"; break;
                    case ABS_TILT_X:   tmp = "TILT_X";   break;
                    case ABS_TILT_Y:   tmp = "TILT_Y";   break;
                    case ABS_MISC:     tmp = "MISC";     break;
                    default:           tmp = "UNKNOWN";  break;
                    }
                    printf("Absolute %s %d", tmp, event.value);
                    break;
                case EV_MSC: printf("Misc"); break;
                case EV_LED: printf("Led");  break;
                case EV_SND: printf("Snd");  break;
                case EV_REP: printf("Rep");  break;
                case EV_FF:  printf("FF");   break;
                    break;
                }
                printf("\n");
            }
            printf("rc = %d, (%s)\n", rc, strerror(errno));
            close(fd);
        }
    }
    return 0;
}