Re: [PATCH v4 3/4] arm64: dts: qcom: shikra-cqm-evk: Enable display and add ili7807s panel

[Arpit Saini]

Hi Dmitry,

On 9/22/2026 9:33 PM, Dmitry Baryshkov wrote:
> On Wed, Sep 16, 2026 at 02:41:20PM +0530, Nabige Aala wrote:
>> From: Arpit Saini <arpit.saini@xxxxxxxxxxxxxxxx>
>>
>> Enable the Shikra MDSS display subsystem on the Qualcomm
>> Shikra CQM EVK board and add the DLC0697 MIPI DSI display
>> panel node. Pin pm4125_l5 to 1.232V with regulator-allow-set-load
>> for DSI PHY PLL stability.
>>
>> Signed-off-by: Arpit Saini <arpit.saini@xxxxxxxxxxxxxxxx>
>> Signed-off-by: Nabige Aala <nabige.aala@xxxxxxxxxxxxxxxx>
>> ---
>>  arch/arm64/boot/dts/qcom/shikra-cqm-evk.dts | 118 ++++++++++++++++++++++++++++
>>  1 file changed, 118 insertions(+)
>>
>> +
>> +&mdss_dsi0 {
>> +	vdda-supply = <&pm4125_l5>;
>> +
>> +	status = "okay";
>> +
>> +	panel@0 {
>> +		compatible = "dlc,dlc0697", "ilitek,ili7807s";
>> +		reg = <0>;
>> +
>> +		reset-gpios = <&tlmm 3 GPIO_ACTIVE_LOW>;
>> +
>> +		vddi-supply = <&pm4125_l15>;
>> +		avdd-supply = <&vreg_disp_p>;
>> +		avee-supply = <&vreg_disp_n>;
>> +
>> +		pinctrl-0 = <&panel_rst_n &panel_te_pin &panel_bl_en>;
> 
> As far as I remember, your panel_bl_en enables an external regulator.
> Why is it not described in this way?
> 

panel_bl_en is a Qcom's daughter card specific platform signal , it does not feed into the panel.

It is a board-level GPIO on the CQM EVK daughter card used purely for
platform power sequencing.

Adding panel_bl_en as an external regulator would be misleading and incorrect from a hardware perspective,
as it is not directly going into the panel.

for the CQM EVK, the backlight is MIPI DCS driven and panel_bl_en is a
platform-specific sequencing pin, making pinctrl states the
appropriate binding here.

Could you please take a look at earlier discussion we had and let us know your thoughts ?

https://lore.kernel.org/all/29ca6303-4368-4aeb-b82f-039aa252780a@xxxxxxxxxxxxxxxx/

Thanks,
Arpit