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This article mainly shows you "sample analysis of camera drivers in linux", which is easy to understand and well-organized. I hope it can help you solve your doubts. Let me lead you to study and learn the article "sample analysis of camera drivers in linux".

For modern embedded devices, especially mobile phones, the camera is a very important device. Many students buy mobile phones, look at their appearance, and then look at the camera to take pictures. Therefore, from a certain point of view, the camera is the main application function of various manufacturers. So, how does linux support cameras?

1. Code directory address

Drivers/media

2. V4l2 framework

At present, the camera on linux is designed according to the v4l2 framework, and its address is located in drivers/media/v4l2-core.

3. To see how Samsung soc supports camera, you can check drviers/media/platform/Kconfig

Config VIDEO_S3C_CAMIF tristate "Samsung S3C24XX/S3C64XX SoC Camera Interface driver" depends on VIDEO_V4L2 & & I2C & & VIDEO_V4L2_SUBDEV_API depends on PM depends on ARCH_S3C64XX | | PLAT_S3C24XX | | COMPILE_TEST depends on HAS_DMA select VIDEOBUF2_DMA_CONTIG-- help--- This is a v4l2 driver for s3c24xx and s3c64xx SoC series camera host interface (CAMIF). To compile this driver as a module, choose M here: the module will be called s3c-camif.

4. Confirm from Kconfig that it only depends on its own directory except VIDEO_V4L2 and VIDEO_V4L2_SUBDEV_API

Obj-$ (CONFIG_VIDEO_S3C_CAMIF) + = s3c-camif/

5. Continue to look at the code structure of the s3c-camif directory

# Makefile for s3c244x/s3c64xx CAMIF driver s3c-camif-objs: = camif-core.o camif-capture.o camif-regs.o obj-$ (CONFIG_VIDEO_S3C_CAMIF) + = s3c-camif.o

6. Makefile has made it very clear that it mainly relies on three camif-*.c files

By reading, confirm that camif-core.c is a registration document

Camif-regs.c is a register read-write file

Camif-capture.c is the main operation file and interface file.

7. Confirm the function operation interface of v4l2

Static const struct v4l2_ioctl_ops s3c_camif_ioctl_ops = {.vidioc _ querycap = s3c_camif_vidioc_querycap, .vidioc _ enum_input = s3c_camif_vidioc_enum_input, .vidioc _ g_input = s3c_camif_vidioc_g_input, .vidioc _ s_input = s3c_camif_vidioc_s_input, .vidioc _ enum_fmt_vid_cap = s3c_camif_vidioc_enum_fmt .vidioc _ try_fmt_vid_cap = s3c_camif_vidioc_try_fmt, .vidioc _ s_fmt_vid_cap = s3c_camif_vidioc_s_fmt, .vidioc _ g_fmt_vid_cap = s3c_camif_vidioc_g_fmt, .vidioc _ g_selection = s3c_camif_g_selection, .vidioc _ s_selection = s3c_camif_s_selection, .vidioc _ reqbufs = s3c_camif_reqbufs .vidioc _ querybuf = s3c_camif_querybuf, .vidioc _ prepare_buf = s3c_camif_prepare_buf, .vidioc _ create_bufs = s3c_camif_create_bufs, .vidioc _ qbuf = s3c_camif_qbuf, .vidioc _ dqbuf = s3c_camif_dqbuf, .vidioc _ streamon = s3c_camif_streamon, .vidioc _ streamoff = s3c_camif_streamoff, .vidioc _ subscribe_event = v4l2_ctrl_subscribe_event .vidioc _ unsubscribe_event = v4l2_event_unsubscribe, .vidioc _ log_status = v4l2_ctrl_log_status,}

And

649 static const struct v4l2_file_operations s3c_camif_fops = {650.owner = THIS_MODULE, 651.open = s3c_camif_open, 652.release = s3c_camif_close, 653.Poll = s3c_camif_poll, 654.unmanned _ ioctl = video_ioctl2, 655.mmap = s3c_camif_mmap, 656}

8. Like sd, the interface is relatively simple, but an in-depth understanding of camera,v4l2 cannot be bypassed.

This is the same as SD card, usb, asoc.

The above is all the contents of the article "sample Analysis of camera drivers in linux". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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