linux-kernel - Re: [PATCH v2 0/2] Add waveshare 7inch touchscreen panel support

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Date: Tue, 16 Jan 2024 10:34:16 +0100
From: "neil.armstrong@...aro.org" <neil.armstrong@...aro.org>
To: Shengyang Chen <shengyang.chen@...rfivetech.com>,
 "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
 "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>
Cc: "quic_jesszhan@...cinc.com" <quic_jesszhan@...cinc.com>,
 "sam@...nborg.org" <sam@...nborg.org>, "airlied@...il.com"
 <airlied@...il.com>, "daniel@...ll.ch" <daniel@...ll.ch>,
 "maarten.lankhorst@...ux.intel.com" <maarten.lankhorst@...ux.intel.com>,
 "mripard@...nel.org" <mripard@...nel.org>,
 "tzimmermann@...e.de" <tzimmermann@...e.de>,
 "robh+dt@...nel.org" <robh+dt@...nel.org>,
 "krzysztof.kozlowski+dt@...aro.org" <krzysztof.kozlowski+dt@...aro.org>,
 "conor+dt@...nel.org" <conor+dt@...nel.org>,
 "wahrenst@....net" <wahrenst@....net>,
 "dave.stevenson@...pberrypi.com" <dave.stevenson@...pberrypi.com>,
 "thierry.reding@...il.com" <thierry.reding@...il.com>,
 Changhuang Liang <changhuang.liang@...rfivetech.com>,
 Keith Zhao <keith.zhao@...rfivetech.com>,
 Jack Zhu <jack.zhu@...rfivetech.com>,
 "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 0/2] Add waveshare 7inch touchscreen panel support

On 16/01/2024 10:32, Shengyang Chen wrote:
> Hi, Neil
> 
> Thanks for your comment.
> 
>> -----Original Message-----
>> From: neil.armstrong@...aro.org <neil.armstrong@...aro.org>
>> Sent: 2024年1月9日 19:19
>> To: Shengyang Chen <shengyang.chen@...rfivetech.com>;
>> devicetree@...r.kernel.org; dri-devel@...ts.freedesktop.org
>> Cc: quic_jesszhan@...cinc.com; sam@...nborg.org; airlied@...il.com;
>> daniel@...ll.ch; maarten.lankhorst@...ux.intel.com; mripard@...nel.org;
>> tzimmermann@...e.de; robh+dt@...nel.org;
>> krzysztof.kozlowski+dt@...aro.org; conor+dt@...nel.org; wahrenst@....net;
>> dave.stevenson@...pberrypi.com; thierry.reding@...il.com; Changhuang
>> Liang <changhuang.liang@...rfivetech.com>; Keith Zhao
>> <keith.zhao@...rfivetech.com>; Jack Zhu <jack.zhu@...rfivetech.com>;
>> linux-kernel@...r.kernel.org
>> Subject: Re: [PATCH v2 0/2] Add waveshare 7inch touchscreen panel support
>>
>> Hi,
>>
>> On 09/01/2024 08:09, Shengyang Chen wrote:
>>> This patchset adds waveshare 7inch touchscreen panel support for the
>>> StarFive JH7110 SoC.
>>
>> Could you precise which SKU you're referring to ? is it 19885 =>
>> https://www.waveshare.com/7inch-dsi-lcd.htm ?
>>
> 
> yes, it is
> sorry for confusing you.
> 
>> Are you sure it requires different timings from the RPi one ? In the Waveshare
>> wiki it explicitly uses the rpi setup (vc4-kms-dsi-7inch) to drive it:
>> https://www.waveshare.com/wiki/7inch_DSI_LCD
>>
> 
> Referring to Keith's answer
> https://lists.freedesktop.org/archives/dri-devel/2023-December/434200.html
> the panel timing value is generated to fit phy's bitrate and prevent overflow and underflow.
> 
> Referring to the suggestion, we may try other timing from panel-simple to drive the panel.

Please implement a mode_fixup in your DSI host driver instead.

Neil

> 
>> Neil
>>
>>>
>>>
>>> changes since v1:
>>> - Rebased on tag v6.7.
>>>
>>> patch 1:
>>> - Gave up original changing.
>>> - Changed the commit message.
>>> - Add compatible in panel-simple.yaml
>>>
>>> patch 2:
>>> - Gave up original changing.
>>> - Changed the commit message.
>>> - Add new mode for the panel in panel-simple.c
>>>
>>> v1:
>>> https://patchwork.kernel.org/project/dri-devel/cover/20231124104451.44
>>> 271-1-shengyang.chen@...rfivetech.com/
>>>
>>> Shengyang Chen (2):
>>>     dt-bindings: display: panel: panel-simple: Add compatible property for
>>>       waveshare 7inch touchscreen panel
>>>     gpu: drm: panel: panel-simple: add new display mode for waveshare
>>>       7inch touchscreen panel
>>>
>>>    .../bindings/display/panel/panel-simple.yaml  |  2 ++
>>>    drivers/gpu/drm/panel/panel-simple.c          | 28
>> +++++++++++++++++++
>>>    2 files changed, 30 insertions(+)
>>>
> 
> 
> Best Regards,
> Shengyang