mbox series

[v2,0/2] Add waveshare 7inch touchscreen panel support

Message ID 20240109070949.23957-1-shengyang.chen@starfivetech.com (mailing list archive)
Headers show
Series Add waveshare 7inch touchscreen panel support | expand

Message

Shengyang Chen Jan. 9, 2024, 7:09 a.m. UTC
This patchset adds waveshare 7inch touchscreen panel support
for the StarFive JH7110 SoC.


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/20231124104451.44271-1-shengyang.chen@starfivetech.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(+)

Comments

Neil Armstrong Jan. 9, 2024, 11:19 a.m. UTC | #1
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 ?

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

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/20231124104451.44271-1-shengyang.chen@starfivetech.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(+)
>
Stefan Wahren Jan. 9, 2024, 5:21 p.m. UTC | #2
Hi Neil,

Am 09.01.24 um 12:19 schrieb neil.armstrong@linaro.org:
> 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 ?
>
> 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
i don't have an anser for your question, but the Raspberry Pi vendor
tree use different timings than the Mainline kernel:

https://github.com/raspberrypi/linux/commit/222b9baa97cc4c880d040a8c6a5da80d6a42c8e8

Additionally the
arm64/boot/dts/freescale/imx8mm-venice-gw72xx-0x-rpidsi.dtso suggests
that it uses the Raspberry Pi 7inch, but uses the timings of
powertip,ph800480t013-idf02 from panel-simple.

Maybe Shengyang could test these timings with the Waveshare touch. At
the end this rely on a proper implementation on the underlying drivers.

Sorry, for adding more confusion.

Regards
>
> 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/20231124104451.44271-1-shengyang.chen@starfivetech.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(+)
>>
>
Dave Stevenson Jan. 9, 2024, 5:28 p.m. UTC | #3
Hi

On Tue, 9 Jan 2024 at 11:19, <neil.armstrong@linaro.org> wrote:
>
> 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 ?
>
> 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

I raise the same question.

Keith Zhao earlier submitted effectively the same set of patches [1]
and the response for the updated timing was:
<quote>
My platform dphy tx hardware has certain limitations.
Only supports integer multiples of 10M bitrate:
such as 160M ,170M, 180M,190M,...1G(max)

as common dphy bitrate = pixclock*bpp/lanes.
This value cannot match successfully in most cases.

so in order to match bitrate , I choose a bitrate value around
pixclock*bpp/lanes,
Prevent overflow and underflow by fine-tuning the timing parameters:-(
that will make the new timming value.
</quote>

I then suggested mode_fixup should be used in the DSI host driver, and
Keith acknowledged that.

Is this new timing still because of the DSI host requirement?

  Dave

[1] https://lists.freedesktop.org/archives/dri-devel/2023-December/434150.html

> 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/20231124104451.44271-1-shengyang.chen@starfivetech.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(+)
> >
>
Shengyang Chen Jan. 16, 2024, 9:32 a.m. UTC | #4
Hi, Neil

Thanks for your comment.

> -----Original Message-----
> From: neil.armstrong@linaro.org <neil.armstrong@linaro.org>
> Sent: 2024年1月9日 19:19
> To: Shengyang Chen <shengyang.chen@starfivetech.com>;
> devicetree@vger.kernel.org; dri-devel@lists.freedesktop.org
> Cc: quic_jesszhan@quicinc.com; sam@ravnborg.org; airlied@gmail.com;
> daniel@ffwll.ch; maarten.lankhorst@linux.intel.com; mripard@kernel.org;
> tzimmermann@suse.de; robh+dt@kernel.org;
> krzysztof.kozlowski+dt@linaro.org; conor+dt@kernel.org; wahrenst@gmx.net;
> dave.stevenson@raspberrypi.com; thierry.reding@gmail.com; Changhuang
> Liang <changhuang.liang@starfivetech.com>; Keith Zhao
> <keith.zhao@starfivetech.com>; Jack Zhu <jack.zhu@starfivetech.com>;
> linux-kernel@vger.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.

> 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@starfivetech.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
Neil Armstrong Jan. 16, 2024, 9:34 a.m. UTC | #5
On 16/01/2024 10:32, Shengyang Chen wrote:
> Hi, Neil
> 
> Thanks for your comment.
> 
>> -----Original Message-----
>> From: neil.armstrong@linaro.org <neil.armstrong@linaro.org>
>> Sent: 2024年1月9日 19:19
>> To: Shengyang Chen <shengyang.chen@starfivetech.com>;
>> devicetree@vger.kernel.org; dri-devel@lists.freedesktop.org
>> Cc: quic_jesszhan@quicinc.com; sam@ravnborg.org; airlied@gmail.com;
>> daniel@ffwll.ch; maarten.lankhorst@linux.intel.com; mripard@kernel.org;
>> tzimmermann@suse.de; robh+dt@kernel.org;
>> krzysztof.kozlowski+dt@linaro.org; conor+dt@kernel.org; wahrenst@gmx.net;
>> dave.stevenson@raspberrypi.com; thierry.reding@gmail.com; Changhuang
>> Liang <changhuang.liang@starfivetech.com>; Keith Zhao
>> <keith.zhao@starfivetech.com>; Jack Zhu <jack.zhu@starfivetech.com>;
>> linux-kernel@vger.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@starfivetech.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
Shengyang Chen Jan. 16, 2024, 9:44 a.m. UTC | #6
Hi, Stefan

Thanks for your comment and suggestion.

> -----Original Message-----
> From: Stefan Wahren <wahrenst@gmx.net>
> Sent: 2024年1月10日 1:22
> To: neil.armstrong@linaro.org; Shengyang Chen
> <shengyang.chen@starfivetech.com>; devicetree@vger.kernel.org;
> dri-devel@lists.freedesktop.org
> Cc: quic_jesszhan@quicinc.com; sam@ravnborg.org; airlied@gmail.com;
> daniel@ffwll.ch; maarten.lankhorst@linux.intel.com; mripard@kernel.org;
> tzimmermann@suse.de; robh+dt@kernel.org;
> krzysztof.kozlowski+dt@linaro.org; conor+dt@kernel.org;
> dave.stevenson@raspberrypi.com; thierry.reding@gmail.com; Changhuang
> Liang <changhuang.liang@starfivetech.com>; Keith Zhao
> <keith.zhao@starfivetech.com>; Jack Zhu <jack.zhu@starfivetech.com>;
> linux-kernel@vger.kernel.org
> Subject: Re: [PATCH v2 0/2] Add waveshare 7inch touchscreen panel support
> 
> Hi Neil,
> 
> Am 09.01.24 um 12:19 schrieb neil.armstrong@linaro.org:
> > 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 ?
> >
> > 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
> i don't have an anser for your question, but the Raspberry Pi vendor tree use
> different timings than the Mainline kernel:
> 
> https://github.com/raspberrypi/linux/commit/222b9baa97cc4c880d040a8c6a5
> da80d6a42c8e8
> 
> Additionally the
> arm64/boot/dts/freescale/imx8mm-venice-gw72xx-0x-rpidsi.dtso suggests that
> it uses the Raspberry Pi 7inch, but uses the timings of
> powertip,ph800480t013-idf02 from panel-simple.
> 
> Maybe Shengyang could test these timings with the Waveshare touch. At the
> end this rely on a proper implementation on the underlying drivers.
> 
> Sorry, for adding more confusion.
> 
Thanks for suggestion.
We will try other timing from panel-simple.
Maybe we are not going to commit new panel timing patch
if we find useful timing from panel-simple to drive the panel.

> Regards
> >
> > 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/20231124104451.4
> >> 4271-1-shengyang.chen@starfivetech.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(+)
> >>
> >

thanks

Best Regards,
Shengyang
Shengyang Chen Jan. 16, 2024, 9:54 a.m. UTC | #7
Hi, Dave

Thanks for your comment

> -----Original Message-----
> From: Dave Stevenson <dave.stevenson@raspberrypi.com>
> Sent: 2024年1月10日 1:29
> To: neil.armstrong@linaro.org
> Cc: Shengyang Chen <shengyang.chen@starfivetech.com>;
> devicetree@vger.kernel.org; dri-devel@lists.freedesktop.org;
> quic_jesszhan@quicinc.com; sam@ravnborg.org; airlied@gmail.com;
> daniel@ffwll.ch; maarten.lankhorst@linux.intel.com; mripard@kernel.org;
> tzimmermann@suse.de; robh+dt@kernel.org;
> krzysztof.kozlowski+dt@linaro.org; conor+dt@kernel.org; wahrenst@gmx.net;
> thierry.reding@gmail.com; Changhuang Liang
> <changhuang.liang@starfivetech.com>; Keith Zhao
> <keith.zhao@starfivetech.com>; Jack Zhu <jack.zhu@starfivetech.com>;
> linux-kernel@vger.kernel.org
> Subject: Re: [PATCH v2 0/2] Add waveshare 7inch touchscreen panel support
> 
> Hi
> 
> On Tue, 9 Jan 2024 at 11:19, <neil.armstrong@linaro.org> wrote:
> >
> > 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 ?
> >
> > 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
> 
> I raise the same question.
> 
> Keith Zhao earlier submitted effectively the same set of patches [1] and the
> response for the updated timing was:
> <quote>
> My platform dphy tx hardware has certain limitations.
> Only supports integer multiples of 10M bitrate:
> such as 160M ,170M, 180M,190M,...1G(max)
> 
> as common dphy bitrate = pixclock*bpp/lanes.
> This value cannot match successfully in most cases.
> 
> so in order to match bitrate , I choose a bitrate value around pixclock*bpp/lanes,
> Prevent overflow and underflow by fine-tuning the timing parameters:-( that
> will make the new timming value.
> </quote>
> 
> I then suggested mode_fixup should be used in the DSI host driver, and Keith
> acknowledged that.
> 
> Is this new timing still because of the DSI host requirement?
> 

Actually, the mode fixup method is referred and used in DSI's new patch
https://patchwork.kernel.org/project/dri-devel/patch/20240109072516.24328-3-shengyang.chen@starfivetech.com/
you can check it in cdns_dsi_jh7110_update()
This code is being reviewed and may need to be optimized later.

And the timing in this panel patch is tested and verified but we did not try other timing. Sorry about that.
As Stefan suggested, we should try other timing from panel-simple for example "powertip,ph800480t013-idf02".

If the other timing from panel-simple can be used, maybe it is not necessary for us to submit panel timing patch.

>   Dave
> 
> [1]
> https://lists.freedesktop.org/archives/dri-devel/2023-December/434150.html
> 
> > 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.
> > > 44271-1-shengyang.chen@starfivetech.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
Shengyang Chen Jan. 16, 2024, 10:02 a.m. UTC | #8
Hi, Neil

> -----Original Message-----
> From: neil.armstrong@linaro.org <neil.armstrong@linaro.org>
> Sent: 2024年1月16日 17:34
> To: Shengyang Chen <shengyang.chen@starfivetech.com>;
> devicetree@vger.kernel.org; dri-devel@lists.freedesktop.org
> Cc: quic_jesszhan@quicinc.com; sam@ravnborg.org; airlied@gmail.com;
> daniel@ffwll.ch; maarten.lankhorst@linux.intel.com; mripard@kernel.org;
> tzimmermann@suse.de; robh+dt@kernel.org;
> krzysztof.kozlowski+dt@linaro.org; conor+dt@kernel.org; wahrenst@gmx.net;
> dave.stevenson@raspberrypi.com; thierry.reding@gmail.com; Changhuang
> Liang <changhuang.liang@starfivetech.com>; Keith Zhao
> <keith.zhao@starfivetech.com>; Jack Zhu <jack.zhu@starfivetech.com>;
> linux-kernel@vger.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@linaro.org <neil.armstrong@linaro.org>
> >> Sent: 2024年1月9日 19:19
> >> To: Shengyang Chen <shengyang.chen@starfivetech.com>;
> >> devicetree@vger.kernel.org; dri-devel@lists.freedesktop.org
> >> Cc: quic_jesszhan@quicinc.com; sam@ravnborg.org; airlied@gmail.com;
> >> daniel@ffwll.ch; maarten.lankhorst@linux.intel.com;
> >> mripard@kernel.org; tzimmermann@suse.de; robh+dt@kernel.org;
> >> krzysztof.kozlowski+dt@linaro.org; conor+dt@kernel.org;
> >> wahrenst@gmx.net; dave.stevenson@raspberrypi.com;
> >> thierry.reding@gmail.com; Changhuang Liang
> >> <changhuang.liang@starfivetech.com>; Keith Zhao
> >> <keith.zhao@starfivetech.com>; Jack Zhu <jack.zhu@starfivetech.com>;
> >> linux-kernel@vger.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.
> 

The mode fixup method is already used. As reference:
https://patchwork.kernel.org/project/dri-devel/patch/20240109072516.24328-3-shengyang.chen@starfivetech.com/
you can check it in cdns_dsi_jh7110_update(). 
This code is being reviewed and may need to be optimized later.

> 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@starfivetech.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

Best Regards,
Shengyang