From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Ripard Subject: Re: [PATCH 4/4] arm64: DTS: allwinner: a64: enable ANX6345 bridge on Teres-I Date: Fri, 17 May 2019 11:08:45 +0200 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/mixed; boundary="===============0557666394==" Return-path: In-Reply-To: <20190517101353.3e86d696@blackhole.lan> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Torsten Duwe Cc: Mark Rutland , devicetree , David Airlie , linux-kernel , dri-devel , Vasily Khoruzhick , Chen-Yu Tsai , Rob Herring , Thierry Reding , Laurent Pinchart , Harald Geyer , Sean Paul , arm-linux , Icenowy Zheng List-Id: devicetree@vger.kernel.org --===============0557666394== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="rsrvm5wgc3yqgwap" Content-Disposition: inline --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-- --===============0557666394== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Content-Disposition: inline X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KZHJpLWRldmVs IG1haWxpbmcgbGlzdApkcmktZGV2ZWxAbGlzdHMuZnJlZWRlc2t0b3Aub3JnCmh0dHBzOi8vbGlz dHMuZnJlZWRlc2t0b3Aub3JnL21haWxtYW4vbGlzdGluZm8vZHJpLWRldmVs --===============0557666394==--