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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_NEOMUTT autolearn=ham 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 EF984C46460 for ; Fri, 17 May 2019 09:09:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C83FC20818 for ; Fri, 17 May 2019 09:09:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728729AbfEQJJA (ORCPT ); Fri, 17 May 2019 05:09:00 -0400 Received: from relay4-d.mail.gandi.net ([217.70.183.196]:33565 "EHLO relay4-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728072AbfEQJI7 (ORCPT ); Fri, 17 May 2019 05:08:59 -0400 X-Originating-IP: 80.215.154.25 Received: from localhost (unknown [80.215.154.25]) (Authenticated sender: maxime.ripard@bootlin.com) by relay4-d.mail.gandi.net (Postfix) with ESMTPSA id E48BAE000E; Fri, 17 May 2019 09:08:45 +0000 (UTC) Date: Fri, 17 May 2019 11:08:45 +0200 From: Maxime Ripard To: Torsten Duwe Cc: Vasily Khoruzhick , David Airlie , Daniel Vetter , Rob Herring , Mark Rutland , Thierry Reding , Chen-Yu Tsai , Andrzej Hajda , Laurent Pinchart , Icenowy Zheng , Sean Paul , Harald Geyer , dri-devel , devicetree , arm-linux , linux-kernel Subject: Re: [PATCH 4/4] arm64: DTS: allwinner: a64: enable ANX6345 bridge on Teres-I Message-ID: <20190517090845.oujs33nplbaxcyun@flea> References: <20190514155911.6C0AC68B05@newverein.lst.de> <20190514160241.9EAC768C7B@newverein.lst.de> <20190515093141.41016b11@blackhole.lan> <20190516154820.GA10431@lst.de> <20190516164859.GB10431@lst.de> <20190517072738.deohh5fly4jxms7k@flea> <20190517101353.3e86d696@blackhole.lan> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="rsrvm5wgc3yqgwap" Content-Disposition: inline In-Reply-To: <20190517101353.3e86d696@blackhole.lan> User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --rsrvm5wgc3yqgwap Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, May 17, 2019 at 10:14:18AM +0200, Torsten Duwe wrote: > On Fri, 17 May 2019 09:27:38 +0200 > Maxime Ripard wrote: > > > On Thu, May 16, 2019 at 06:48:59PM +0200, Torsten Duwe wrote: > > > On Thu, May 16, 2019 at 09:06:41AM -0700, Vasily Khoruzhick wrote: > > > > > > > > Driver can talk to the panel over AUX channel only after t1+t3, > > > > t1 is up to 10ms, t3 is up to 200ms. > > > > > > This is after power-on. The boot loader needs to deal with this. > > > > The bootloader can deal with it, but the kernel will also need to. The > > bootloader might not be doing this because it's not been updated, the > > regulator might have been disabled between the time the kernel was > > started and the time the bridge driver probes, etc. > > No, you cannot practically switch off this voltage. It supports _all_ > the devices I mentioned. In fact, the PMIC needs to enable it initially, > and then it takes some time before the SoC can access the MMC and read > the SPL from it, just because of exactly these 3.3V. Then the boot > loader starts, and later the eDP bridge gets initialised. All these devices can be unused, disabled, or compiled as modules. > In *theory*, albeit a very daring one, I could imagine a very deep > sleep mode that can only be ended by pressing the power button, which > should still work without DCDC1. Only then, a description of the panel > would be required. But I probably missed something and even this does > not work. > > So for all current practical purposes, we can assume the Teres-I panel > to be powered properly and providing valid EDID; nothing to worry about > in software. You're creating a generic binding for all the users of that bridge, while considering only the specific case of the Teres-I. Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com --rsrvm5wgc3yqgwap Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRcEzekXsqa64kGDp7j7w1vZxhRxQUCXN56HQAKCRDj7w1vZxhR xZh0AP4+w3VFZULGFliCxVroYWWP58DFQSolgLvZtZpZrGVBeAEA6zaZsM+cYTlD SY3UolrT94qs2Tr0bSG5TvhQwQ111wk= =giob -----END PGP SIGNATURE----- --rsrvm5wgc3yqgwap--