From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id ED7D3C433EF for ; Thu, 27 Jan 2022 09:36:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232206AbiA0Jg2 (ORCPT ); Thu, 27 Jan 2022 04:36:28 -0500 Received: from out4-smtp.messagingengine.com ([66.111.4.28]:39459 "EHLO out4-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232134AbiA0Jg1 (ORCPT ); Thu, 27 Jan 2022 04:36:27 -0500 Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by mailout.nyi.internal (Postfix) with ESMTP id BFCE15C0135; Thu, 27 Jan 2022 04:36:26 -0500 (EST) Received: from mailfrontend2 ([10.202.2.163]) by compute5.internal (MEProxy); Thu, 27 Jan 2022 04:36:26 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cerno.tech; h=cc :cc:content-type:date:date:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:sender:subject :subject:to:to; s=fm2; bh=WA1psq6av3hb8CPQl+q6JR0R81+NLrXh6/dARD GQBMI=; b=owi4N6M20BirIVtp0UbfhSC75hSNeZj7CZ5dKBmyciE3+kFlsIN3ij LM9i1OFq+wrwIaP+jJqLgTaluZhjBDViaFHN536jfbN97ovmiEovSKi4iwjPhi5e 68UBSnb+cC1+5YN6IQGezYqmR2koVKzlYDiYsj0bbKAU8lB0vEd4PB7tsWkwLKgN fhuyRUvpopOTsO3BB5wouZdlTz+gr+2vxdvvkRI+XRHi3DYoI4O/+evIEkYPe93P HQ4jnnDEEUCMzseu+YGvB3tRWRNxgSn++XjPh5hZaI11ck+M1v9+feNVbwmzyLzz LfDPZ+52qq8tjLLrMMF+yNUtJJybb24w== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:date:date:from:from :in-reply-to:in-reply-to:message-id:mime-version:references :reply-to:sender:subject:subject:to:to:x-me-proxy:x-me-proxy :x-me-sender:x-me-sender:x-sasl-enc; s=fm1; bh=WA1psq6av3hb8CPQl +q6JR0R81+NLrXh6/dARDGQBMI=; b=LCBoMUXhBCT4xL1aYFnrGHHoYEMAlEee0 vkvZsJWSOLgFuIpm6EBq1+CGXEN1LpcnEB9cu6aWCzGQu/Y+ceGesYVTOSGhgHsr 5F93rGO1lMUlItni+TOzA3G1Gd0k/pc/yV31gWTb07tfz6VCO4FApRZ+M02Il4j/ KYrH86H5pOztPDpXbO0Is4wfz5b9zdoYgMPNxe5imwDMocYO8Gm54CbE5GxFpR6p Cs70awsUUxK97vRGzrtPKVSPBvpLlLmpeb2Fql12Mk8uYgEJZ/DmrAP8qIJK8NY+ Bvxebf8jXBE3rx4EGIHxNHJRAXBA1BhMdeCvkMYrBSQigMNMR981Q== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvvddrfeefgddthecutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenuc fjughrpeffhffvuffkfhggtggujgesghdtreertddtudenucfhrhhomhepofgrgihimhgv ucftihhprghrugcuoehmrgigihhmvgestggvrhhnohdrthgvtghhqeenucggtffrrghtth gvrhhnpeejkeekffdtfffhhfevvddutefgtdeljeevffevvddvteegledtgfeghfehvdei ffenucffohhmrghinhepkhgvrhhnvghlrdhorhhgnecuvehluhhsthgvrhfuihiivgeptd enucfrrghrrghmpehmrghilhhfrhhomhepmhgrgihimhgvsegtvghrnhhordhtvggthh X-ME-Proxy: Received: by mail.messagingengine.com (Postfix) with ESMTPA; Thu, 27 Jan 2022 04:36:26 -0500 (EST) Date: Thu, 27 Jan 2022 10:36:24 +0100 From: Maxime Ripard To: Rob Herring Cc: Noralf =?utf-8?Q?Tr=C3=B8nnes?= , thierry.reding@gmail.com, sam@ravnborg.org, dave.stevenson@raspberrypi.com, david@lechnology.com, devicetree@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: Re: [PATCH 1/3] dt-bindings: display: add bindings for MIPI DBI compatible SPI panels Message-ID: <20220127093624.6gozbr6gl4ft66fz@houat> References: <20220123172520.48741-1-noralf@tronnes.org> <20220123172520.48741-2-noralf@tronnes.org> <931fab73-3a91-fda0-4af3-b48a1ad3c742@tronnes.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="g3d2usy72o624st2" Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org --g3d2usy72o624st2 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi Rob, On Mon, Jan 24, 2022 at 10:42:37AM -0600, Rob Herring wrote: > On Mon, Jan 24, 2022 at 10:28 AM Noralf Tr=F8nnes wr= ote: > > > > > > > > Den 24.01.2022 17.08, skrev Rob Herring: > > > On Sun, Jan 23, 2022 at 11:25 AM Noralf Tr=F8nnes wrote: > > >> > > >> Add binding for MIPI DBI compatible SPI panels. > > > > > > I'm sure we already have MIPI DBI panels. What's this for? > > > > > > > It aims to use one driver to cover all MIPI DBI panels where the > > controller setup is loaded from userspace in a firmware file. >=20 > What's the solution when the user wants a splash screen in the > bootloader and also wants multiple panels supported? >=20 > Also, 1 driver doesn't dictate 1 compatible. A one to many > relationship is fine and makes the decision entirely the OS's. >=20 > > The cover > > letter points to the discussion where Maxime proposed this: > > > > https://lore.kernel.org/dri-devel/20211129093946.xhp22mvdut3m67sc@houat/ >=20 > The proposal there is: >=20 > > compatible =3D "panel-spi"; > > model =3D "panel-from-random-place-42"; >=20 > The same thing can be accomplished with this: >=20 > compatible =3D "panel-from-random-place-42", "panel-spi"; >=20 > What's the advantage of hijacking 'model'? So, the main issue is that a panel is essentially two things: a controller and the actual panel. The controller has an initialization sequence of its own, and part of it is parameters to match the panel. So you can have identical controllers that won't have the same initialization sequence because they don't have the same panel. I was assuming that a compatible would be more about the controller, so we needed something else, thus "model" Maxime --g3d2usy72o624st2 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRcEzekXsqa64kGDp7j7w1vZxhRxQUCYfJnmAAKCRDj7w1vZxhR xcsTAP9/qENaW6RTVPJRf9nDXmouAAgilNGFGvNurPNgkK2Z5gEA3T1Wy4CPOm+V Y3A3EtaJ75EIrXoMlF4PFQRNg9UMHAw= =J/lt -----END PGP SIGNATURE----- --g3d2usy72o624st2--