How to port Raspberry Pi's 7-inch touchscreen with Stm32mp157c-dk2?

[HArsl]

I have been trying to port touchscreen with Stm32mp157c-dk2 without success. Actually, touchscreen has 15 pins but Stm32 has 20 pins and I handled the unmatched pins on Stm in logical way. Rest of the pins match but no screen seen. Do I have to make adjustment in the SW side?

Best regards,

Halil

[AntonioST · Accepted solution]

I think the display you mention is this one

https://www.raspberrypi.org/products/raspberry-pi-touch-display/

I never used it, so the information below are not fully verified.

From HW side you need to connect several wires: GND, +3V3, +5V, I2C_SCL/SDA and the 6 wires for DSI CK,D0,D1 N and P.

Then you need to modify the device tree accordingly to

https://elixir.bootlin.com/linux/v4.19.9/source/Documentation/devicetree/bindings/display/panel/raspberrypi,7inch-touchscreen.txt

and recompile the kernel adding the configuration option CONFIG_DRM_PANEL_RASPBERRYPI_TOUCHSCREEN

[HArsl]

Dear Antonio,

Thank you very much. I will try it and then give a feedback.

[HArsl]

Hi Antonio,

I have tried what you said me and resulted without success. I reconfigured the device tree accordingly the link and connected panel with connector just seen dark. I attached the device tree file below.

Best

Halil

[BSE]

Hi Halil,

I know your Question is a couple of months old but:

Have you solved the Problem and if so, how?

We've run into the same problem, but we solved the problem with the backlight Control:

You have to add these lines into the &i2c1 block:

&i2c1 {
      #address-cells = <1>;
      #size-cells = <0>;
 
lcd@45 {
        compatible = "raspberrypi,7inch-touchscreen-panel";
        reg = <0x45>;
        status="okay";
        port {
          panel_in: endpoint {
            remote-endpoint = <&dsi_out>;
          };
        };
};
[...SOME OTHER STUFF ...]
}

Comment out the Panel@0 block in &dsi to avoid compiling Errors due to the "dsi_out" port.

When the system boots up, the backlight of the display is activated - but there are just vertical lines and no proper screen output...

[ARicc.1]

Hi All,

any development on this topic? I'm interested too.

Thanks,

Aldo

[BlotCoo]

Did you ever get this working? I've spent the past few weeks trying to even get the backlight to turn on. Tried using both the example DTS given by ST and the configuration you've posted but no luck.