摄像头驱动代码

摄像头驱动代码通常需要根据具体的摄像头型号来编写。一般来说，摄像头驱动代码需要实现摄像头的基本功能，例如初始化、配置、打开和关闭等。同时，还需要实现摄像头的数据采集功能，将采集到的图像数据传输到应用程序中进行处理和显示。

在Linux系统中，摄像头驱动代码通常采用V4L2（Video for Linux 2）接口进行开发。V4L2是Linux内核提供的视频设备驱动接口，提供了一套标准接口，方便应用程序对视频设备进行访问。

下面是一个简单的V4L2摄像头驱动代码示例：

#include <linux/videodev2.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/mman.h>

int main(int argc, char **argv) {
    int fd;
    struct v4l2_capability cap;
    struct v4l2_format fmt;
    struct v4l2_requestbuffers reqbuf;
    struct v4l2_buffer buf;
    void *buffer;
    unsigned int i, nbufs;

    fd = open("/dev/video0", O_RDWR);
    if (fd < 0) {
        perror("Failed to open camera");
        exit(EXIT_FAILURE);
    }

    if (ioctl(fd, VIDIOC_QUERYCAP, &cap) < 0) {
        perror("Failed to query capabilities");
        close(fd);
        exit(EXIT_FAILURE);
    }

    if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) {
        perror("Camera does not support video capture");
        close(fd);
        exit(EXIT_FAILURE);
    }

    memset(&fmt, 0, sizeof(fmt));
    fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    fmt.fmt.pix.width = 640;
    fmt.fmt.pix.height = 480;
    fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
    if (ioctl(fd, VIDIOC_S_FMT, &fmt) < 0) {
        perror("Failed to set format");
        close(fd);
        exit(EXIT_FAILURE);
    }

    memset(&reqbuf, 0, sizeof(reqbuf));
    reqbuf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    reqbuf.memory = V4L2_MEMORY_MMAP;
    reqbuf.count = 4;
    if (ioctl(fd, VIDIOC_REQBUFS, &reqbuf) < 0) {
        perror("Failed to request buffers");
        close(fd);
        exit(EXIT_FAILURE);
    }

    nbufs = reqbuf.count;
    buffer = malloc(nbufs * fmt.fmt.pix.sizeimage);
    if (!buffer) {
        perror("Failed to allocate buffer memory");
        close(fd);
        exit(EXIT_FAILURE);
    }

    for (i = 0; i < nbufs; i++) {
        memset(&buf, 0, sizeof(buf));
        buf.type = reqbuf.type;
        buf.memory = reqbuf.memory;
        buf.index = i;
        if (ioctl(fd, VIDIOC_QUERYBUF, &buf) < 0) {
            perror("Failed to query buffer");
            free(buffer);
            close(fd);
            exit(EXIT_FAILURE);
        }

        if (mmap(NULL, buf.length, PROT_READ | PROT_WRITE, MAP_SHARED, fd, buf.m.offset) == MAP_FAILED) {
            perror("Failed to map buffer");
            free(buffer);
            close(fd);
            exit(EXIT_FAILURE);
        }
    }

    for (i = 0; i < nbufs; i++) {
        memset(&buf, 0, sizeof(buf));
        buf.type = reqbuf.type;
        buf.memory = reqbuf.memory;
        buf.index = i;
        if (ioctl(fd, VIDIOC_QBUF, &buf) < 0) {
            perror("Failed to enqueue buffer");
            free(buffer);
            close(fd);
            exit(EXIT_FAILURE);
        }
    }

    enum v4l2_buf_type type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    if (ioctl(fd, VIDIOC_STREAMON, &type) < 0) {
        perror("Failed to start streaming");
        free(buffer);
        close(fd);
        exit(EXIT_FAILURE);
    }

    while (1) {
        memset(&buf, 0, sizeof(buf));
        buf.type = reqbuf.type;
        buf.memory = reqbuf.memory;
        if (ioctl(fd, VIDIOC_DQBUF, &buf) < 0) {
            perror("Failed to dequeue buffer");
            free(buffer);
            close(fd);
            exit(EXIT_FAILURE);
        }

        // Process captured image data here

        if (ioctl(fd, VIDIOC_QBUF, &buf) < 0) {
            perror("Failed to enqueue buffer");
            free(buffer);
            close(fd);
            exit(EXIT_FAILURE);
        }
    }

    free(buffer);
    close(fd);

    return 0;
}

这段代码实现了一个简单的摄像头驱动程序，它使用V4L2接口从摄像头中采集图像数据，并将其传输到应用程序中进行处理和显示。需要注意的是，这段代码只是一个示例，实际的摄像头驱动程序会更加复杂，需要根据具体的摄像头型号进行编写。