Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.35 as permitted sender) client-ip=23.128.96.35;
Date:   Wed, 6 Dec 2023 15:40:21 +0000
From:   Conor Dooley <conor@kernel.org>
To:     Shengyang Chen <shengyang.chen@starfivetech.com>
Cc:     devicetree@vger.kernel.org, dri-devel@lists.freedesktop.org,
        neil.armstrong@linaro.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,
        florian.fainelli@broadcom.com,
        bcm-kernel-feedback-list@broadcom.com, eric@anholt.net,
        thierry.reding@gmail.com, changhuang.liang@starfivetech.com,
        keith.zhao@starfivetech.com, jack.zhu@starfivetech.com,
        linux-rpi-kernel@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 1/2] dt-bindings: display: panel: raspberrypi: Add
 compatible property for waveshare 7inch touchscreen panel
Message-ID: <20231206-isolating-smoked-b490952029d0@spud>
References: <20231124104451.44271-1-shengyang.chen@starfivetech.com>
 <20231124104451.44271-2-shengyang.chen@starfivetech.com>
 <20231124-lesser-sinister-7f9cd7b80e35@spud>
 <2d48e460-e46e-431f-bd7b-e34ebe73a40c@starfivetech.com>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha256;
        protocol="application/pgp-signature"; boundary="4u5wDHCnw45IR5T9"
Content-Disposition: inline
In-Reply-To: <2d48e460-e46e-431f-bd7b-e34ebe73a40c@starfivetech.com>
Precedence: bulk


--4u5wDHCnw45IR5T9
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

On Wed, Dec 06, 2023 at 05:43:48PM +0800, Shengyang Chen wrote:
> Hi, Conor
>=20
> On 2023/11/24 20:31, Conor Dooley wrote:
> > On Fri, Nov 24, 2023 at 06:44:50PM +0800, Shengyang Chen wrote:
> >> The waveshare 7inch touchscreen panel is a kind of raspberrypi pi
> >> panel
> >=20
> > Can you be more specific about what "is a kind of rpi panel" means?
> > Are they using identical chips as controllers or something like that?
> >=20
>=20
> Wareshare panel has same i2c slave address and registers address with=20
> the original raspberry pi panel. They both use Atmel firmware and they
> got same reg id. It can be operated by using the driver of raspberry pi d=
river
> after some change of the code. So I suppose it may be a kind of raspberry=
 pi panel=20
> and discribe it in this way. It's my own judgement. Sorry about that.
> Maybe just like Dave said, It cloned the behaviour of the raspberri pi pa=
nel.
> I will change the discribtion in next version to not make other confused.
>=20
> By the way, we will try Stefan's method before next version.=20
> The method we used in this patch may be abandoned if Stefan's method is v=
erified in our platform.
> At that time yaml may also be changed to fit new method.

I don't know what Stefan's approach is, but I do not think that a
bindings patch should be dropped. The waveshare might be a clone, but it
is a distinct device. If the same driver can control both, then the
compatible setups that should be permitted are:
compatible =3D "raspberrypi,7inch-touchscreen-panel";
and
compatible =3D "waveshare,7inch-touchscreen-panel", "raspberrypi,7inch-touc=
hscreen-panel";

Cheers,
Conor.

> >> and it can be drived by panel-raspberrypi-touchscreen.c.
> >> Add compatible property for it.
> >>=20
> >> Signed-off-by: Keith Zhao <keith.zhao@starfivetech.com>
> >> Signed-off-by: Shengyang Chen <shengyang.chen@starfivetech.com>
> >> ---
> >>  .../bindings/display/panel/raspberrypi,7inch-touchscreen.yaml | 4 +++-
> >>  1 file changed, 3 insertions(+), 1 deletion(-)
> >>=20
> >> diff --git a/Documentation/devicetree/bindings/display/panel/raspberry=
pi,7inch-touchscreen.yaml b/Documentation/devicetree/bindings/display/panel=
/raspberrypi,7inch-touchscreen.yaml
> >> index 22a083f7bc8e..e4e6cb4d4e5b 100644
> >> --- a/Documentation/devicetree/bindings/display/panel/raspberrypi,7inc=
h-touchscreen.yaml
> >> +++ b/Documentation/devicetree/bindings/display/panel/raspberrypi,7inc=
h-touchscreen.yaml
> >> @@ -22,7 +22,9 @@ description: |+
> >> =20
> >>  properties:
> >>    compatible:
> >> -    const: raspberrypi,7inch-touchscreen-panel
> >> +    enum:
> >> +      - raspberrypi,7inch-touchscreen-panel
> >> +      - waveshare,7inch-touchscreen-panel
> >> =20
> >>    reg:
> >>      const: 0x45
> >> --=20
> >> 2.17.1
> >>=20
>=20
>=20
> thanks.
>=20
> Best Regards,
> Shengyang
>=20

--4u5wDHCnw45IR5T9
Content-Type: application/pgp-signature; name="signature.asc"

-----BEGIN PGP SIGNATURE-----

iHUEABYIAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCZXCV5QAKCRB4tDGHoIJi
0lu+AP9S+mBLWn0c2W0GfWmBKz/Iv+21lMnJlHnXSv1Hh16NNgEA+55r2ib/hc12
310USnVcRIuSzUWHXrASafnfq5Sd6Qc=
=NiWe
-----END PGP SIGNATURE-----

--4u5wDHCnw45IR5T9--