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

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

Hi Krzysztof , Dmitry

On 6/6/2026 5:43 PM, Dmitry Baryshkov wrote:
> On Tue, May 26, 2026 at 04:02:45PM +0530, Arpit Saini wrote:
>> 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
> 
> "Invalid referrer"
> 
I should have shared the full part No. DLC0697AAL21MF
https://www.dlcdisplay.com/Resources/1760134404595535872-435-15.html
>>>>>>
>>>>>> 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.
> 
> Still unanswered.
> 
Display daughter card is Qualcomm board.

I misunderstood it, I shouldn't added the backlight-en-gpios
in my dt-bindings, I apologize for not answering clearly earlier.

The backlight enable GPIO is on the Qualcomm daughter card, not on the 
panel connector. I will remove backlight-en-gpios from the panel binding 
and model the backlight enable gpio at the board level.
>>>
>>>>
>>>> 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.
> 
> Much easier. Call drm_panel_of_backlight() and if there is no error and
> panel->backlight is still NULL, then create your own backlight device.
> 
okay I understood, I will not use the has_dcs_backlight.
will proceed as you told.
>>
>> Please let me know,if I am missing something.
>>
>> Thanks,
>> Arpit
>>
>>
>