AM62A3-Q1: Dummy Driver for /dev/fb0

Hi,

I am not sure I understand what you mean by custom driver. On AM62A, we have Linxu running on the Acores and there is a TIDSS driver that is used for frame buffer processing.

Regards,
Krunal

Hi Krunal,

I want to output 1920x1080 resolution data in DPI pins. But in my custom design I don't have any bridge IC to convert to HDMI. So, the si9022's driver wont work. What I want is a dummy drm driver to output data in DPI with various predefined resolutions and clocks. Is there any dummy driver for drm?

Hi,

I don't have any example of such dummy DRM driver and I would recommend you to check with DRM community.

Regards,
Krunal

Hello Krunal,
I just want to output 1920x1080 resolution data on DPI pins in RGB format without using any IC.
Please suggest me the changes in device tree to achieve this.

Hi,

This is not a typical usecase and we don't support the above usecase in our SDK. As I stated earlier, my recommendation would be to check with DRM community for suggestions. The only thing I can recommend as an experiment would be be to trick the driver into thinking it has a LCD panel connected on the other side. The LCD panels typically don't have an EDID so DSS doesn't know if something is connected or not and it will generate HSYNC/VSYNC/DATA based on your timing information. You can review the following thread on how to connect a DPI panel: https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1270408/am623-dss-dpi-display-on-am62x/4811783?tisearch=e2e-sitesearch&keymatch=DPI%252520dts#4811783. The only thing would be to figure out the timing values for 1920x1080 panel.

Regards,
Krunal

Hi Krunal,
      We are use ADV7511 bridge IC and with the bellow device tree modifications:

adv7511w: adv7511w@39 {
	compatible = "adi,adv7511w";
	 reg = <0x39>, <0x66>;
	 reg-names = "main", "edid";
	clocks = <&ce_clock>;
	clock-names = "cec";
	adi,input-depth = <8>;  
	adi,input-colorspace = "rgb"; 
	adi,input-clock = "1x";  

	adi,input-style = <3>;
	adi,input-justification = "right";
	ports {
		#address-cells = <1>;
		#size-cells = <0>;
 
		port@0 {
			reg = <0>;
			adv7511w_in: endpoint { 
				remote-endpoint = <&dpi1_out>;
			};
		};
	
		port@1 {
			reg = <1>;
			adv7511w_out: endpoint {
				remote-endpoint = <&hdmi_connector_in>;
			};
		};
        };
    };

The driver is loaded successfully and we are able to detect the IC on the i2c address, getting the pixel clock as well but not getting data on video out pins. also through kmsprint command we can see HDMI Connector as connected as soon as we plug in.
Getting one error by tidss_encoder,c 
[ 19.347732] tidss 30200000.dss: tidss_encoder_atomic_check: No bus_formats in connected display.

Please guide how do I get VOUT data.

I am confused by your ask because initially you wanted a dummy driver and now you are connecting adv bridge. Has your setup changed?

Regards,
Krunal