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 X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B569DC06511 for ; Tue, 2 Jul 2019 08:14:26 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8E5C12184C for ; Tue, 2 Jul 2019 08:14:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="dHDD866N" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8E5C12184C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bootlin.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender:Content-Type:Cc: List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: In-Reply-To:MIME-Version:References:Message-ID:Subject:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=45M5IzW80B6zPRTWKqVSVnhPqZyhCYHyI1S85wn8Crg=; b=dHDD866N+JOBJ0qQFj693pbB4 viYS6Ep/AjtA4tZrxvP7vKH2nAMWdrkSzsDKumNGVysIK0c//PZb/8+gE9UmjZr5QZUcAbIXUOykI I/6Vp0acZeVqPsdpnpD++zfz/OselFZDALkbns51nsnfUuEOrVw6PZLup8QG7GV2FDRrglVTLITQQ 22Dh0hRKMMlS33rO/A131PvtrMrqC/xUljzMWDrjW45FiyHDrDD7LiiWm7YMTZFeKLpadIHv5N6ji ojKKL1Hzxu9uHzd7SBaW9+pADboPom1u4dMQISWdragnbaM+/vFNyTNuKLeNmH8mF4nKqX8sQ1jp0 pTR6wDpYw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hiDvc-0002SA-Hv; Tue, 02 Jul 2019 08:14:16 +0000 Received: from relay9-d.mail.gandi.net ([217.70.183.199]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1hiDvX-0002QQ-VA for linux-arm-kernel@lists.infradead.org; Tue, 02 Jul 2019 08:14:14 +0000 X-Originating-IP: 90.89.68.76 Received: from localhost (lfbn-1-10718-76.w90-89.abo.wanadoo.fr [90.89.68.76]) (Authenticated sender: maxime.ripard@bootlin.com) by relay9-d.mail.gandi.net (Postfix) with ESMTPSA id 29E16FF807; Tue, 2 Jul 2019 08:13:47 +0000 (UTC) Date: Tue, 2 Jul 2019 10:13:46 +0200 From: Maxime Ripard To: Andrzej Hajda Subject: Re: [PATCH v2 7/7] arm64: dts: allwinner: a64: enable ANX6345 bridge on Teres-I Message-ID: <20190702081346.4hlb53qcajhz4ckl@flea> References: <20190605120237.ekmytfxcwbjaqy3x@flea> <20190607062802.m5wslx3imiqooq5a@flea> <20190607094030.GA12373@lst.de> <66707fcc-b48e-02d3-5ed7-6b7e77d53266@samsung.com> <20190612152022.c3cfhp4cauhzhfyr@flea> <20190701095842.fvganvycce2cy7jn@flea> <64471471-5b4d-3c1f-a0e3-e02ee78ca23c@samsung.com> MIME-Version: 1.0 In-Reply-To: <64471471-5b4d-3c1f-a0e3-e02ee78ca23c@samsung.com> User-Agent: NeoMutt/20180716 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190702_011412_320787_FACC4A43 X-CRM114-Status: GOOD ( 30.82 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , devicetree , Sean Paul , David Airlie , Greg Kroah-Hartman , linux-kernel , dri-devel , Chen-Yu Tsai , Rob Herring , Torsten Duwe , Laurent Pinchart , Daniel Vetter , Harald Geyer , Thierry Reding , Thomas Gleixner , arm-linux , Icenowy Zheng Content-Type: multipart/mixed; boundary="===============5448406954130883482==" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org --===============5448406954130883482== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="ysvumhfqulaacx3l" Content-Disposition: inline --ysvumhfqulaacx3l Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Mon, Jul 01, 2019 at 02:27:51PM +0200, Andrzej Hajda wrote: > On 01.07.2019 11:58, Maxime Ripard wrote: > > On Fri, Jun 28, 2019 at 12:39:32PM +0200, Andrzej Hajda wrote: > >> On 12.06.2019 17:20, Maxime Ripard wrote: > >>>> I am not sure if I understand whole discussion here, but I also do not > >>>> understand whole edp-connector thing. > >>> The context is this one: > >>> https://patchwork.freedesktop.org/patch/257352/?series=51182&rev=1 > >>> https://patchwork.freedesktop.org/patch/283012/?series=56163&rev=1 > >>> https://patchwork.freedesktop.org/patch/286468/?series=56776&rev=2 > >>> > >>> TL;DR: This bridge is being used on ARM laptops that can come with > >>> different eDP panels. Some of these panels require a regulator to be > >>> enabled for the panel to work, and this is obviously something that > >>> should be in the DT. > >>> > >>> However, we can't really describe the panel itself, since the vendor > >>> uses several of them and just relies on the eDP bus to do its job at > >>> retrieving the EDIDs. A generic panel isn't really working either > >>> since that would mean having a generic behaviour for all the panels > >>> connected to that bus, which isn't there either. > >>> > >>> The connector allows to expose this nicely. > >> As VESA presentation says[1] eDP is based on DP but is much more > >> flexible, it is up to integrator (!!!) how the connection, power > >> up/down, initialization sequence should be performed. Trying to cover > >> every such case in edp-connector seems to me similar to panel-simple > >> attempt failure. Moreover there is no such thing as physical standard > >> eDP connector. Till now I though DT connector should describe physical > >> connector on the device, now I am lost, are there some DT bindings > >> guidelines about definition of a connector? > > This might be semantics but I guess we're in some kind of grey area? > > > > Like, for eDP, if it's soldered I guess we could say that there's no > > connector. But what happens if for some other board, that signal is > > routed through a ribbon? > > > > You could argue that there's no physical connector in both cases, or > > that there's one in both, or one for the ribbon and no connector for > > the one soldered in. > > This is not about ribbon vs soldering. It is about usage: this > connection is static across the whole life of the device (except > exceptional things: repair, non-standard usage, etc). It doesn't have to be. > And "the real connector" is (at least for me) something where > end-user can connect/disconnect different things: USB, HDMI, > ethernet, etc. And obviously to be functional it should be somehow > standardized. So even if there could be some grey area, I do not see > it here. Well, if there's a ribbon connector, then you have a physical connector, with the end user being able to connect / disconnect various displays. It might not be the case with actual products, but it's pretty common with SBCs to have that signal routed through a connector, and the user has several options to connect a display to it. The line really is blurred. > >> 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 > > And what if some panel can be used with this pseudo-connecter and in > some different hw directly? Code duplication? DT overlays? Overlays are a solution, but I would advocate to always have the connector. Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com --ysvumhfqulaacx3l Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRcEzekXsqa64kGDp7j7w1vZxhRxQUCXRsSOgAKCRDj7w1vZxhR xULUAPsGQYzNIZSTC25p24UViIRLulmthcOhzTK4JDdmTudgfAD+LA/mKeRDEVmr 5I2K+qvDzz8yXwdP9AtgR/XK8mhHSQ8= =dLkQ -----END PGP SIGNATURE----- --ysvumhfqulaacx3l-- --===============5448406954130883482== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel --===============5448406954130883482==--