From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Ripard Subject: Re: [PATCH v2 7/7] arm64: dts: allwinner: a64: enable ANX6345 bridge on Teres-I Date: Tue, 9 Jul 2019 16:21:55 +0200 Message-ID: <20190709142155.2blclgbqapjeifv3@flea> References: <20190607062802.m5wslx3imiqooq5a@flea> <20190607094030.GA12373@lst.de> <66707fcc-b48e-02d3-5ed7-6b7e77d53266@samsung.com> <20190612152022.c3cfhp4cauhzhfyr@flea> <20190701095842.fvganvycce2cy7jn@flea> <20190709085532.cdqv7whuesrjs64c@flea> <72E7C765-3660-413A-8450-94BE4B3D1345@aosc.io> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="en37fuotj5a3o4w2" Return-path: Content-Disposition: inline In-Reply-To: <72E7C765-3660-413A-8450-94BE4B3D1345@aosc.io> Sender: linux-kernel-owner@vger.kernel.org To: Icenowy Zheng Cc: linux-arm-kernel@lists.infradead.org, Vasily Khoruzhick , Mark Rutland , devicetree , Sean Paul , David Airlie , Greg Kroah-Hartman , linux-kernel , dri-devel , Andrzej Hajda , Chen-Yu Tsai , Rob Herring , Torsten Duwe , Laurent Pinchart , Daniel Vetter , Harald Geyer , Thierry Reding , Thomas Gleixner List-Id: devicetree@vger.kernel.org --en37fuotj5a3o4w2 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Jul 09, 2019 at 04:58:35PM +0800, Icenowy Zheng wrote: > > > =E4=BA=8E 2019=E5=B9=B47=E6=9C=889=E6=97=A5 GMT+08:00 =E4=B8=8B=E5=8D=884= :55:32, Maxime Ripard =E5=86=99=E5=88=B0: > >On Mon, Jul 08, 2019 at 05:49:21PM -0700, Vasily Khoruzhick wrote: > >> > > Maybe instead of edp-connector one would introduce integrator's > >specific > >> > > connector, for example with compatible > >"olimex,teres-edp-connector" > >> > > which should follow edp abstract connector rules? This will be at > >least > >> > > consistent with below presentation[1] - eDP requirements depends > >on > >> > > integrator. Then if olimex has standard way of dealing with > >panels > >> > > present in olimex/teres platforms the driver would then create > >> > > drm_panel/drm_connector/drm_bridge(?) according to these rules, I > >guess. > >> > > Anyway it still looks fishy for me :), maybe because I am not > >> > > familiarized with details of these platforms. > >> > > >> > That makes sense yes > >> > >> Actually, it makes no sense at all. Current implementation for > >anx6345 > >> driver works fine as is with any panel specified assuming panel > >delays > >> are long enough for connected panel. It just doesn't use panel > >timings > >> from the driver. Creating a platform driver for connector itself > >looks > >> redundant since it can't be reused, it doesn't describe actual > >> hardware and it's just defeats purpose of DT by introducing > >> board-specific code. > > > >I'm not sure where you got the idea that the purpose of DT is to not > >have any board-specific code. > > > >It's perfectly fine to have some, that's even why there's a compatible > >assigned to each and every board. > > > >What the DT is about is allowing us to have a generic behaviour that > >we can detect: we can have a given behaviour for a given board, and a > >separate one for another one, and this will be evaluated at runtime. > > > >This is *exactly* what this is about: we can have a compatible that > >sets a given, more specific, behaviour (olimex,teres-edp-connector) > >while saying that this is compatible with the generic behaviour > >(edp-connector). That way, any OS will know what quirk to apply if > >needed, and if not that it can use the generic behaviour. > > > >And we could create a generic driver, for the generic behaviour if > >needed. > > > >> There's another issue: if we introduce edp-connector we'll have to > >> specify power up delays somewhere (in dts? or in platform driver?), > >so > >> edp-connector doesn't really solve the issue of multiple panels with > >> same motherboard. > > > >And that's what that compatible is about :) > > Maybe we can introduce a connector w/o any driver just like hdmi-connecto= r? Ironically, a driver for it has been sent yesterday :) But yeah, we can definitely do that too. Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com --en37fuotj5a3o4w2 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRcEzekXsqa64kGDp7j7w1vZxhRxQUCXSSjAwAKCRDj7w1vZxhR xRd1AQCJ5jZZvccoYKMTlhIFwESGq/tLGx3Ao78XQTTrIK5CFAEA11fhHaijvh3D nQ4CuXzwsgPAxXOwMwPH8TV3F9oC/Aw= =S7iw -----END PGP SIGNATURE----- --en37fuotj5a3o4w2--