linux-kernel - Re: [PATCH v1 1/4] dt-bindings: input: Add Himax HX83102J touchscreen

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Message-ID:
 <TY0PR06MB5611AE812B72B349E85118D59E342@TY0PR06MB5611.apcprd06.prod.outlook.com>
Date: Wed, 27 Mar 2024 15:48:48 +0800
From: Allen Lin <allencl_lin@...mail.com>
To: Conor Dooley <conor@...nel.org>
Cc: Conor Dooley <conor.dooley@...rochip.com>, Rob Herring <robh@...nel.org>, 
	dmitry.torokhov@...il.com, krzysztof.kozlowski+dt@...aro.org, 
	conor+dt@...nel.org, jikos@...nel.org, benjamin.tissoires@...hat.com, 
	linux-input@...r.kernel.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 1/4] dt-bindings: input: Add Himax HX83102J touchscreen

Conor Dooley <conor@...nel.org> 於 2024年3月27日 週三 上午3:28寫道：
>
> On Tue, Mar 26, 2024 at 06:40:28PM +0800, Allen Lin wrote:
> > Conor Dooley <conor.dooley@...rochip.com> 於 2024年3月26日 週二 下午4:48寫道：
> > >
> > > On Tue, Mar 26, 2024 at 01:46:56PM +0800, Allen Lin wrote:
> > > > Conor Dooley <conor@...nel.org> 於 2024年3月23日 週六 上午2:34寫道：
> > > > >
> > > > > On Fri, Mar 22, 2024 at 01:30:09PM -0500, Rob Herring wrote:
> > > > > > On Fri, Mar 22, 2024 at 05:54:08PM +0000, Conor Dooley wrote:
> > > > > > > On Fri, Mar 22, 2024 at 04:56:03PM +0800, Allen_Lin wrote:
> > > > > > > > Add the HX83102j touchscreen device tree bindings documents.
> > > > > > > > HX83102j is a Himax TDDI touchscreen controller.
> > > > > > > > It's power sequence should be bound with a lcm driver, thus it
> > > > > > > > needs to be a panel follower. Others are the same as normal SPI
> > > > > > > > touchscreen controller.
> > > > > > > >
> > > > > > > > Signed-off-by: Allen_Lin <allencl_lin@...mail.com>
> > > > > > >
> > > > > > > note to self/Krzysztof/Rob:
> > > > > > > There was a previous attempt at this kind of device. This version looks
> > > > > > > better but might be incomplete given there's a bunch more properties in
> > > > > > > that patchset:
> > > > > > > https://lore.kernel.org/all/20231017091900.801989-1-tylor_yang@himax.corp-partner.google.com/
> > > > > >
> > > > > > Those don't look like properties we want coming back.
> > > > >
> > > > > Oh, I don't want most of them coming back either. There are some
> > > > > supplies in there though that I think we would like to come back, no?
> > > > > Maybe this particular device doesn't have any supplies, but that doesn't
> > > > > really seem credible.
> > > >
> > > > We will use Firmware-name in Device Tree.
> > >
> > > > For power supply settings, because there may be other device using
> > > > same regulator.
> > >
> > > If there are other devices using the same regulator is it more
> > > important that you document it so that it doesn't get disabled by the
> > > other users.
> > >
> > > > We plan to define it as an optional property for user to control in
> > > > next release.
> > >
> > > I don't see how the regulator would not be required, the device doesn't
> > > function without power.
> > >
> > > Thanks,
> > > Conor.
> >
> > I will set power supply as required.
> > The description of power supply as below,
> >
> > properties:
> >   vccd-supply:
> >     description: A phandle for the regualtor supplying IO power. Should be own
> >                  by TPIC only.
>
> What does "owned by TPIC" only mean? Why would the vccd supply not be
> allowed to be shared with another device?
>
> > This works for TP digital IO only, main power is
> >                  given by display part VSP/VSN power source which is controlled
> >                  by lcm driver.
>
> What drivers control things doesn't really matter here, we're just
> describing the hardware. If there's another supply to the controller,
> then document it too please.
>

Below is IC power sequence introduction.
https://github.com/HimaxSoftware/Doc/tree/main/Himax_Chipset_Power_Sequence

TDDI IC, which means Touch and Display Driver is integrated in one IC,
So some power supplies will be controlled by Display driver.

In yaml Document, can we just list power supplies controlled by touch driver?

Thanks,
Allen