From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Pinchart Subject: Re: [RESEND PATCH v3 06/11] drm: add DT bindings documentation for atmel-hlcdc-dc driver Date: Mon, 21 Jul 2014 15:26:12 +0200 Message-ID: <2273675.A51UonkrgF@avalon> References: <1404751384-5077-1-git-send-email-boris.brezillon@free-electrons.com> <20140721143321.5bda6ea9@bbrezillon> <20140721125624.GF15238@ulmo> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0475406756==" Return-path: In-Reply-To: <20140721125624.GF15238@ulmo> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Thierry Reding Cc: Mark Rutland , devicetree@vger.kernel.org, Nicolas Ferre , dri-devel@lists.freedesktop.org, Alexandre Belloni , Bo Shen , Lee Jones , Jean-Jacques Hiblot , Samuel Ortiz , Tim Niemeyer , Jean-Christophe Plagniol-Villard , linux-pwm@vger.kernel.org, Pawel Moll , Ian Campbell , Rob Herring , Andrew Victor , linux-arm-kernel@lists.infradead.org, Thomas Petazzoni , Kumar Gala List-Id: devicetree@vger.kernel.org --===============0475406756== Content-Type: multipart/signed; boundary="nextPart3588957.OQjje9jzoQ"; micalg="pgp-sha1"; protocol="application/pgp-signature" --nextPart3588957.OQjje9jzoQ Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="us-ascii" Hi Thierry, On Monday 21 July 2014 14:56:26 Thierry Reding wrote: > On Mon, Jul 21, 2014 at 02:33:21PM +0200, Boris BREZILLON wrote: > > On Mon, 21 Jul 2014 14:15:16 +0200 Thierry Reding wrote: > >> On Fri, Jul 18, 2014 at 04:51:52PM +0200, Boris BREZILLON wrote: > >>> On Tue, 15 Jul 2014 12:31:37 +0200 Thierry Reding wrote: > >>>> On Tue, Jul 15, 2014 at 12:06:19PM +0200, Boris BREZILLON wrote:= > >>>>> On Mon, 14 Jul 2014 12:05:43 +0200 Thierry Reding wrote: > >>>>>> On Mon, Jul 07, 2014 at 06:42:59PM +0200, Boris BREZILLON wrot= e: [snip] > >>>>>>> + - atmel,panel: Should contain a phandle with 2 parameters. > >>>>>>> + The first cell is a phandle to a DRM panel device > >>>>>>> + The second cell encodes the RGB mode, which can take the > >>>>>>> following values: + * 0: RGB444 > >>>>>>> + * 1: RGB565 > >>>>>>> + * 2: RGB666 > >>>>>>> + * 3: RGB888 > >>>>>>=20 > >>>>>> These are properties of the panel and should be obtained from > >>>>>> the panel directly rather than an additional cell in this > >>>>>> specifier. > >>>>>=20 > >>>>> Okay. > >>>>> What's the preferred way of doing this ? > >>>>> What about defining an rgb-mode property in the panel node. [snip] > >>>> Also, like Laurent said, this shouldn't go into the device tree,= > >>>> since it's already implied by the panel's compatible value, so w= e'd > >>>> be duplicating information. > >>>=20 > >>> Again, this is not necessarily true (depending on your board desi= gn). > >>> One can decide to connect an RGB888 panel on an RGB666 bus and co= nnect > >>> the missing pins to ground. > >>=20 > >> I think in that case the board design itself could be considered a= s an > >> RGB888 to RGB666 bridge, and I think that's what the device tree s= hould > >> be describing rather than a panel with a variable number of input > >> formats. > >=20 > > So, you're suggesting to add an RGB to RGB drm_bridge driver (and > > the appropriate DT bindings) to handle this case, right ? >=20 > Yes, exactly. Wouldn't it be possible to implement RGB666 -> RGB888 support in a less= =20 complex way ? A standalone driver to describe signal routing seems like= an=20 overly complex solution to me. I would prefer making the routing a prop= erly of=20 the link instead of a separate device. =2D-=20 Regards, Laurent Pinchart --nextPart3588957.OQjje9jzoQ Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part. Content-Transfer-Encoding: 7Bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAABAgAGBQJTzRT0AAoJEIkPb2GL7hl1f3gH+wUUwsZqOTwdYRHYLdJneW0L LHHxTztWlbK+YuZ/p+gGjpbLf6dJydVrSg0ngTlOcp1XE6TMeIb33hBPDWEriu0o 36txqOFNFXRuWjWgHQQ8XddkOEKvMOKk926ERpqlmPIccV42yBDUJUHbpaguPid1 Uki2paXO/3V4sQ5lP8O43tjpNpdi5SwYGHs7vbl5EAp0CpaKPBGOWA28JzqG58gz Hdpa2uezQu8fENL+pI45BdW8QSZu6kx7Nis9vvBbNUgIuUYcXKjW+YPSb2cqAogm i3Nx0V1gqIP40aoqtTtNWxpDc/PJ8FeR/mqR4TIELnPT4mXPW6/iO1p6YgXM8Lk= =/Zms -----END PGP SIGNATURE----- --nextPart3588957.OQjje9jzoQ-- --===============0475406756== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel --===============0475406756==--