drivers: video: ov2640: add sensor driver for ov2640

[robertszczepanski]

This adds driver for Omnivision OV2640 image sensor.

The driver provides support for:

• Camera initialization.
• 10 camera controls - there is support for old control macros like horizontal and vertical flip, exposure and gain control. There are also new control macros that support brightness, saturation, white balance, contrast, colorbar and quality settings.
• Camera hardware reset.
• 2 output formats - RGB565 and JPEG.
• 10 resolutions in both supported formats (160x120, 176x144, 240x160, 320x240, 352x288, 640x480, 800x600, 1024x768, 1280x1024, 1600x1200).

There is also new node in litex_vexriscv devicetree that represents OV2640 camera.
It has been tested on Arty A7-35T with LiteX SoC. OV2640 camera XCLK set to 24MHz.

[loicpoulain]

This adds driver for Omnivision OV2640 image sensor.

The driver provides support for:

* Camera initialization.

* 10 camera controls - there is support for old control macros like horizontal and vertical flip, exposure and gain control. There are also new control macros that support brightness, saturation, white balance, contrast, colorbar and quality settings.

* Camera hardware reset.

* 2 output formats - RGB565 and JPEG.

There is also new node in litex_vexriscv devicetree that represents OV2640 camera.
It has been tested on Arty A7-35T with LiteX SoC. OV2640 camera XCLK set to 24MHz.

Do you plan to submit a subsequent patch for the image processing/acquisition side of this microcontroller?

[robertszczepanski]

Right now we don't have any subsequent patches for the image processing planned for litex_vexriscv.

[loicpoulain]

Right now we don't have any subsequent patches for the image processing planned for litex_vexriscv.

ok, understood, but how did you test that? have you only tested the control path (i2c) or are you using some downstream driver for data catpure?

[robertszczepanski]

I developed an app that integrates this driver with FastVDMA, Zephyr net driver and shell subsystem. This allows me to write captured image to memory and then transfer it to my PC via Ethernet. After that I am able to convert an image to png (using ffmpeg) and display it on screen.
Shell subsystem with additional commands works great here for camera testing. I am able to get multiple captures (one at the time) with different camera settings without resetting device.

[loicpoulain]

@ro

I developed an app that integrates this driver with FastVDMA, Zephyr net driver and shell subsystem. This allows me to write captured image to memory and then transfer it to my PC via Ethernet. After that I am able to convert an image to png (using ffmpeg) and display it on screen.
Shell subsystem with additional commands works great here for camera testing. I am able to get multiple captures (one at the time) with different camera settings without resetting device.

Ok, thanks for the clarification.

[loicpoulain]

LGTM from a video framework perspective.

[carlescufi]

@robertszczepanski please rebase to the latest main branch

[robertszczepanski]

@carlescufi done :)