From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752183AbaBBSxn (ORCPT ); Sun, 2 Feb 2014 13:53:43 -0500 Received: from smtp1-g21.free.fr ([212.27.42.1]:35476 "EHLO smtp1-g21.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751974AbaBBSxm convert rfc822-to-8bit (ORCPT ); Sun, 2 Feb 2014 13:53:42 -0500 Date: Sun, 2 Feb 2014 19:54:00 +0100 From: Jean-Francois Moine To: Russell King - ARM Linux Cc: dri-devel@lists.freedesktop.org, Dave Airlie , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Rob Clark Subject: Re: [PATCH v5 00/23] Message-ID: <20140202195400.073f4eb4@armhf> In-Reply-To: <20140202182349.GJ26684@n2100.arm.linux.org.uk> References: <20140202124358.GD26684@n2100.arm.linux.org.uk> <20140202190606.6fa193ce@armhf> <20140202182349.GJ26684@n2100.arm.linux.org.uk> X-Mailer: Claws Mail 3.9.3 (GTK+ 2.24.22; arm-unknown-linux-gnueabihf) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2 Feb 2014 18:23:49 +0000 Russell King - ARM Linux wrote: > On Sun, Feb 02, 2014 at 07:06:06PM +0100, Jean-Francois Moine wrote: > > On Sun, 2 Feb 2014 12:43:58 +0000 > > Russell King - ARM Linux wrote: > > > > > On Wed, Jan 29, 2014 at 10:01:22AM +0100, Jean-Francois Moine wrote: > > > > This patch set contains various extensions to the tda998x driver: > > > > > > > > - simplify the i2c read/write > > > > - code cleanup and fix some small errors > > > > - use global constants > > > > - don't read write-only registers > > > > - add DT support > > > > - use IRQ for connection status and EDID read > > > > > > I discussed these patches with Rob Clark recently, and the conclusion > > > we came to is that I'll merge them into a git tree, test them, and > > > once I'm happy I'll send a pull request as appropriate. > > > > > > I'll go through them later today. Those patches which have been re- > > > posted without any change for the last few times (the first few) I'll > > > take into my git tree today so you don't have to keep re-posting them > > > (more importantly, I won't have to keep on looking at them either.) > > > > Thanks. > > > > BTW, I found some problems with the patch 12 'add DT support' you > > already acked: > > > > - the .of_match_table is not needed because the i2c client is created by > > the i2c subsystem from the 'reg' in the DT, > > Okay - may it be a good idea to have someone knowledgable of I2C give it > a review? Sure! There is still a lot of magic in the DT. I used the tda998x in the DT for a long time without .of_match_table and it loaded correctly. I added it in the patch just because my other modules had it. A few days ago, when I moved the tda998x audio codec description in the DT as a subnode of the tda998x i2c, the codec module was not loaded. An of_platform_populate() of the subnodes was needed in the tda998x i2c driver. I could not find why... > > - on encoder_destroy(), the function drm_i2c_encoder_destroy() > > unregisters the i2c client, so, with a DT, a second encoder_init() > > would crash. > > I think this is one of the down-sides of trying to bolt DT into this: > the drm encoder slave support is not designed to cope with an i2c client > device pre-created. > > In fact, I can't see how this stuff comes anywhere close to working in > a DT setup: in such a scenario, you declare that there's a tda998x > device in DT. I2C parses this, and creates an i2c_client itself for > the tda998x. > > When the TDA998x driver initialises, it finds this i2c client and > binds to it, calling tda998x_probe(), which does nothing. > > However, the only way to attach a slave encoder to a DRM device is via > a call to drm_i2c_encoder_init(), which unconditionally calls > i2c_new_device(). This creates a _new_ i2c_client structure, again > unconditionally, for the tda998x. This must be bound by the I2C > subsystem to a driver - hopefully the tda998x driver, which then > calls it's encoder_init function. > > None of this will happen if DT has already created an i2c_client at > the appropriate address, because DRMs i2c_new_device() will fail. > > My hypothesis is that you have other patches to I2C and/or DRM to > sort this out which you haven't been posting with this series. So, > could you please provide some hints as to how this works? I explained how to use the tda998x in a DT context in a message to Jyri Sarha: http://lists.freedesktop.org/archives/dri-devel/2014-January/052936.html -- Ken ar c'hentañ | ** Breizh ha Linux atav! ** Jef | http://moinejf.free.fr/