Re: [PATCH v2] arm64: dts: qcom: sdm845-xiaomi-beryllium: Add DSI and panel bits

Hi,

On Mon, 8 Feb 2021 at 20:11, Konrad Dybcio [off-list ref] wrote:

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+      ports {
+              port@1 {
+                      endpoint {
+                              remote-endpoint = <&tianma_nt36672a_in_0>;
+                              data-lanes = <0 1 2 3>;
+                      };
+              };
+      };

The endpoint has a label, you can simply use &dsi0_out {};.

I didn't get what you meant there. Care to point to some reference dts
snippet please?

sdm845.dtsi, L4139 as of v5.11-rc7:


port@1 {
                        reg = <1>;
                        dsi0_out: endpoint {
                        };
                    };


This means you can essentially do:

&dsi0_out {

    remote-endpoint = <&tianma_nt36672a_in_0>;
    lanes = <0 1 2 3>;

};


in your dt :)

Thank you. Added in v3.

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+              vddpos-supply = <&lab>;
+              vddneg-supply = <&ibb>;

With Angelo's latest series [1] merged in, I reckon you should explicitly configure lab/ibb (like in [2]),
as wrong settings (which CAN BE SET BY THE BOOTLOADER in some instances!!) can lead to hardware damage.

So iirc in the case of beryllium device, these regulators are pre set
by the bootloader and I can't find any reference of we
setting/resetting it explicitly to switch ON the panel and display. So
far default lab/ibb nodes are working fine for us and I'm hesitant to
tinker around anything regulator related that can potentially damage
the hardware. Having said that, I do see lab/ibb nodes being set in
the downstream dts, with relevant soft-start and discharge-resistor
properties and I can try switching to that once the new lab/ibb
changes land upstream.

Regards,
Amit Pundir

I understand your concerns, however we actually did find out that at least one device had LAB/IBB set up by the bootloader in a way that could potentially damage the electronics, so I'm just making you aware. If it works as-is, it's probably OK.

Device seem to be booting fine with downstream labibb regulator node
changes, hence added them in v3 as well. Smoke tested on
5.11.0-rc7-next-20210209.

Regards,
Amit Pundir

Konrad