Received-SPF: pass (google.com: domain of linux-kernel+bounces-43197-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249;
Date: Mon, 29 Jan 2024 17:22:07 +0000
From: Conor Dooley <conor@kernel.org>
To: Quentin Schulz <quentin.schulz@theobroma-systems.com>
Cc: Farouk Bouabid <farouk.bouabid@theobroma-systems.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jirislaby@kernel.org>, Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Heiko Stuebner <heiko@sntech.de>, Rob Herring <robh@kernel.org>,
	linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org,
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org
Subject: Re: [PATCH v4 3/6] dt-bindings: serial: add binding for rs485
 rx-enable state when rs485 is disabled
Message-ID: <20240129-vagrantly-unaired-4224a5febb01@spud>
References: <20240126-dev-rx-enable-v4-0-45aaf4d96328@theobroma-systems.com>
 <20240126-dev-rx-enable-v4-3-45aaf4d96328@theobroma-systems.com>
 <20240128-vagabond-mutilator-cf8dc6ac8a41@spud>
 <da864300-ae0a-43fc-84bd-94e985d8ac73@theobroma-systems.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha256;
	protocol="application/pgp-signature"; boundary="IBCjK9MpjSUCbqHB"
Content-Disposition: inline
In-Reply-To: <da864300-ae0a-43fc-84bd-94e985d8ac73@theobroma-systems.com>


--IBCjK9MpjSUCbqHB
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

On Mon, Jan 29, 2024 at 01:26:51PM +0100, Quentin Schulz wrote:
> Hi Conor,
>=20
> On 1/28/24 18:38, Conor Dooley wrote:
> > On Fri, Jan 26, 2024 at 03:55:12PM +0100, Farouk Bouabid wrote:
> > > RS485 can have a receiver-enable gpio (rx-enable-gpios). When rs485 is
> > > enabled, this gpio, if provided, must be driven active while receivin=
g.
> > > However when RS485 is disabled this gpio should not have an undefined
> > > state. In that case, as DE and RE pins can be connected both to this =
gpio,
> > > if its state is not properly defined, can cause unexpected transceiver
> > > behavior.
> > > This binding depend on rx-enable-gpios to be implemented.
> >=20
> > Why do you need a dedicated property for this when there exists a device
> > specific compatible for the uart on both of the affected rockchip
> > systems?
> >=20
>=20
> This has nothing to do with Rockchip's IP but the HW design of our
> carrierboard, so using the "rockchip,px30-uart" for that (which I assume =
is
> what was suggested here?) is incorrect since it'll also apply to PX30,
> RK3399 and RK3588-based Q7 SoCs we manufacture.
>=20
> Did I understand the suggestion correctly?

Yes you did. That explanation for not being able to use the compatibles
makes sense. However, I can't give you an ack, because reading the
commit message gives me the same feeling as looking at this photo:
https://www.reddit.com/r/pics/comments/f8jyuz/nothing_in_this_image_is_iden=
tifiable/

Sorry,
Conor.

--IBCjK9MpjSUCbqHB
Content-Type: application/pgp-signature; name="signature.asc"

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

iHUEABYIAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCZbfevwAKCRB4tDGHoIJi
0pCUAP9U44UkidVfIFyP9IjWHAPwttaCmGToXZjCv2rwlhJiVwEA1GULoLBIRwGa
1D79uhaA8T7azreJ91+tdhZ26EA4TQQ=
=Ye3s
-----END PGP SIGNATURE-----

--IBCjK9MpjSUCbqHB--