Re: [PATCH 1/2] dt-bindings: display: panel: add Ilitek ILI7807S panel controller

[Arpit Saini <arpit.saini@oss.qualcomm.com>]

Hi Krzysztof , Dmitry

On 5/20/2026 6:56 PM, Dmitry Baryshkov wrote:
> On Wed, May 20, 2026 at 06:10:57PM +0530, Arpit Saini wrote:
>> Hi Krzysztof , Dmitry
>>
>> On 5/19/2026 4:02 PM, Krzysztof Kozlowski wrote:
>>> On Mon, May 18, 2026 at 04:34:12PM +0530, Arpit Saini wrote:
>>>> ILI7807S is a DSI display controller used to drive MIPI-DSI panels.
>>>> The DLC DLC0697 1080x1920 LCD panel is based on this controller.
> 
> I can't find this panel on the DLC website. Do you have a pointer to the
> product page?
> 
https://v4.cecdn.yun300.cn/100001_2012175013/DLC0697AAL21MF-1.pdf
>>>>
>>>> The panel requires a reset GPIO, backlight enable GPIO, I/O voltage
>>>
>>> If panel requires it, so should the binding.
>>>
>> Ack, I will update.
>>> ...
>>>
>>>> +  reg:
>>>> +    maxItems: 1
>>>> +    description: DSI virtual channel
>>>> +
>>>> +  reset-gpios: true
>>>> +
>>>> +  backlight-en-gpios:
>>>> +    description: Backlight enable GPIO (active high)
>>>
>>> What is the name of the pin in ili7807s device?
>>>
>> Display daughter card has WLED driver as well as LCD bias driver.
> 
> What is the display daughter card here? Is it a Qualcomm board or is it
> a part of the panel?
> 
> Also you wrote a lot of text, but you didn't really answer either of the
> quesitons. Is there a GPIO on the panel connector that enables the
> backlight? If not, this is some external supply on your (assumingly)
> daughter card. And it should be modelled accordingly.
> 
>>
>> The WLED driver's Enable is coming from WLED_P1_EN and PWM is coming from
>> LCD_CABC output of the panel.
>>
>> DISPLAY0_BACKLIGHT_ENABLE (GPIO 91) of ITP baseband card ==> WLED_P1_EN of
>> Display Daughter Card (DC)
>>
>> In the display daughter card of Shikra ITP platform, we are not using the
>> external PWM for WLED driver. But connected the CABC output of the panel to
>> the WLED driver. Backlight update is happening using MIPI DCS command which
>> is driving the CABC output (i.e., PWM for WLED).
>>
>> Because of above HW configuration, we need to enable the MIPI DCS brightness
>> update on this panel. The below command of dlc0697_init_sequence() is
>> enabling this.
>> mipi_dsi_dcs_write_seq_multi(dsi_ctx, 0x53, 0x24);
> 
> So, this should be then dependent on the presence of the backlight in
> the DT. Either it is a panel-internal one, or an external one.
> 
>>
>>
>> After checking this, I realized that this panel can be used without the DCS
>> backlight as well when it's using PWM based backlight control.
>>
>> I can add `has_dcs_backlight`  in panel_desc and set it true for dlc0697. I
>> will update bindings and add backlight as optional property.
> 
> Why? Use backlight property instead. It's already there. Anyway, you
> really, really need to describe the panel in the bidings. Not your
> daughter card.
> 
This `has_dcs_backlight` in panel_desc will serves both the purpose, as 
for our current platform constraint , we need to create our own backlight.
But this panel can be used without the DCS
backlight as well when it's using PWM based backlight control.

So in this case I need to implement the backlight as implemented in 
panel-novatek-nt36523.c, panel-himax-hx83121a.c.

with this implementation ,I will remove the backlight from the dt-bindings.

Please let me know,if I am missing something.

Thanks,
Arpit