Re: [PATCH v2 2/4] arm64: dts: qcom: shikra-cqm-evk: Enable display and add ili7807s panel

[Konrad Dybcio]

On 7/10/26 2:47 PM, Dmitry Baryshkov wrote:
> On Fri, Jul 10, 2026 at 02:10:48PM +0200, Konrad Dybcio wrote:
>> On 7/10/26 1:58 PM, Arpit Saini wrote:
>>> Hi Konrad,
>>>
>>> On 7/10/2026 2:31 PM, Arpit Saini wrote:
>>>> Hi Konrad,
>>>>
>>>> On 7/6/2026 3:33 PM, Konrad Dybcio wrote:
>>>>> On 7/6/26 8:04 AM, Nabige Aala wrote:
>>>>>> From: Arpit Saini <arpit.saini@xxxxxxxxxxxxxxxx>

[...]

>>> I just checked,
>>>
>>> Normally the backlight EN pin is controlled by a backlight driver.
>>>
>>> However, this panel uses MIPI DCS based backlight control with no
>>>
>>> separate backlight driver. Since there is no driver to assert gpio91,
>>>
>>> we control it via the panel's pinctrl default state..
>>>
>>> So this is platform specific pin , we need this to enable/disable
>>>
>>> the backlight.
>>
>> Why would the backlight state be so tightly defined by the panel?
>> Disabling or adjusting the backlight level without shutting down
>> the panel is a perfectly valid use case.
>>
>> Take a look at pwm-backlight or gpio-backlight.
> 
> This one is different. The backlight is controlled over the DSI link. In
> this case there is no separate driver for the backlight, the panel
> driver handles it (it needs to be like this for multiple reasons).

Ah, OK I misread the statement above as 'this panel [doesn't use]
MIPI DCS based backlight'

Konrad