Linux/AM5728: VIP minimum sub device driver

Marc48067 said:

I have connected a camera with 16Bit YCbCr 4:2:2 output with embedded sync to the VIP via camera module interface on the AM572xEVM

VIP driver doesn't support 16 bit bus embedded sync (BT.1120). It only supports 8 bit bus embedded sync ie BT656

Marc48067 said:

1. What is the minimum implementation of a sub device driver without configuration capabilities? Is there an example? I had a look at the ov7640.c which is very short, but has i2c which is not needed.

Since the sensor being used is embedded sync, suggest you to look at tvp514x.c driver as a model. You can stub out/remove i2c part if they aren't needed. For ex, you may have to use v4l2_subdev_init() directly instead of v4l2_i2c_subdev_init()

Marc48067 said:

2. How will the device tree entries look like?

DTS entry could look like this

/ {

               cam_name1 {

                              compatible = "<company_id>,<cam_name>";

                              port {

                                             #address-cells = <1>;

                                             #size-cells = <0>;

                                             cam1: endpoint {

                                                            reg = <1>;

                                                            /* or whichever vin port it is connected to */

                                                            remote-endpoint = <&vin1a>;

                                                            pclk-sample = <0>;

                                                            channels = <0>;

                                             };

                              };

               };

};

This should at least allow it to handshake with at a V4L2 framework level as an embedded sync sub-device.

Marc48067 said:

Are media entities and pads needed?

VIP doesn't support media framework, so media entities aren't needed in the sub-device. However, the sub-device does need to support the V4L2 Sub-device API i.e CONFIG_VIDEO_V4L2_SUBDEV_API.