ZYNQMP 使用ov5640摄像头，调用ioct，返回错误-1；
ZYNQMP 硬件描述结构 摄像头MIPI->mipi_csi2_rx_subsyst_0->v_demosaic_0->v_gamma_lut_0->VDMA
root@xilinx-3eg:~# media-ctl -p -d /dev/media0
Media controller API version 5.4.0
Media device information
---[ 392.533450] ov5640_get_fmt
---------------------
driver xilinx-video
model Xilinx Video Composite Device
serial
bus info
hw revision 0x0
driver version 5.4.0
Device topology
- entity 1: video_cap output 0 (1 pad, 1 link)
type Node subtype V4L flags 0
device node name /dev/video0
pad0: Sink
<- "80040000.v_gamma_lut":1 [ENABLED]
- entity 5: ov5640 0-003c (1 pad, 1 link)
type V4L2 subdev subtype Sensor flags 0
device node name /dev/v4l-subdev0
pad0: Source
[fmt:JPEG_1X8/640x480@1/30 field:none colorspace:jpeg xfer:srgb ycbcr:601 quantization:full-range]
-> "80050000.mipi_csi2_rx_subsystem":1 [ENABLED]
- entity 7: 80050000.mipi_csi2_rx_subsystem (2 pads, 2 links)
type V4L2 subdev subtype Unknown flags 0
device node name /dev/v4l-subdev1
pad0: Source
[fmt:UYVY8_1X16/1920x1080 field:none colorspace:srgb]
-> "80060000.v_demosaic":0 [ENABLED]
pad1: Sink
[fmt:UYVY8_1X16/1920x1080 field:none colorspace:srgb]
<- "ov5640 0-003c":0 [ENABLED]
- entity 10: 80060000.v_demosaic (2 pads, 2 links)
type V4L2 subdev subtype Unknown flags 0
device node name /dev/v4l-subdev2
pad0: Sink
[fmt:SRGGB8_1X8/1280x720 field:none colorspace:srgb]
<- "80050000.mipi_csi2_rx_subsystem":0 [ENABLED]
pad1: Source
[fmt:RBG888_1X24/1280x720 field:none colorspace:srgb]
-> "80040000.v_gamma_lut":0 [ENABLED]
- entity 13: 80040000.v_gamma_lut (2 pads, 2 links)
type V4L2 subdev subtype Unknown flags 0
device node name /dev/v4l-subdev3
pad0: Sink
[fmt:RBG888_1X24/1280x720 field:none colorspace:srgb]
<- "80060000.v_demosaic":1 [ENABLED]
pad1: Source
[fmt:RBG888_1X24/1280x720 field:none colorspace:srgb]
-> "video_cap output 0":0 [ENABLED]
操作
fd = open(FILE_V4LSUBDEV,O_RDWR);
if(fd < 0) {
printf("Error opening\r\n");
return -1;
}
struct v4l2_subdev_format fmt;
if(-1 == ioctl(fd,VIDIOC_SUBDEV_G_FMT , &fmt)){
printf("VIDIOC_SUBDEV_G_FMT fail \r\n");
close(fd);
return -1;
}
ioct返回-1
问题解决
struct v4l2_subdev_format fmt;
fmt.which = 1;
fmt.pad = 0;
```c++
```
看看摄像头是不是没有正确连接