Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S938695AbcJTNsC (ORCPT ); Thu, 20 Oct 2016 09:48:02 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:33946 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935752AbcJTNsB (ORCPT ); Thu, 20 Oct 2016 09:48:01 -0400 Subject: Re: [PATCH] ARM: dts: rockchip: add i2c-bus subnode to edp To: =?UTF-8?Q?Heiko_St=c3=bcbner?= , Rob Herring , Mark Rutland References: <1476950845-28242-1-git-send-email-tomeu.vizoso@collabora.com> <7604646.6yosK0XMNL@diego> Cc: linux-kernel@vger.kernel.org, Randy Li , Jon Hunter , Russell King , linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, devicetree@vger.kernel.org From: Tomeu Vizoso Message-ID: <6083453f-08e1-643a-9638-1db38c704aa5@collabora.com> Date: Thu, 20 Oct 2016 15:47:56 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <7604646.6yosK0XMNL@diego> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1874 Lines: 61 On 10/20/2016 03:45 PM, Heiko St?bner wrote: > Am Donnerstag, 20. Oktober 2016, 10:07:25 schrieb Tomeu Vizoso: >> Add an empty 'i2c-bus' subnode to the edp node just so that the I2C core >> doesn't attemp to parse the 'ports' subnode as containing i2c devices. >> >> This is to avoid spurious failure messages such as: >> >> i2c i2c-6: of_i2c: modalias failure on /dp@ff970000/ports > > On the one hand, the edp really has an i2c bus - with its only client the EDID > listening at 0x50 (and maybe 0x30). > > On the other hand, adding an empty bus to the (implementation independent) > devicetree just to make the Linux i2c subsystem happy sounds heavily like a > implementation-specific hack, as the edp i2c bus doesn't leak into the outside > world otherwise. > > I guess this empty i2c bus not being part of the binding document points > heavily into the implementation-specific corner :-) . > > My short search on other patches touching this didn't reveal anything but > maybe this was already discussed somewhere and found to be ok? Here it is: http://www.spinics.net/lists/linux-tegra/msg27862.html Regards, Tomeu > Another option could be to just make of_i2c_register_device silent if > of_modalias_node returns -ENODEV? > > > Heiko > >> Signed-off-by: Tomeu Vizoso >> Cc: Randy Li >> Cc: Jon Hunter >> --- >> arch/arm/boot/dts/rk3288.dtsi | 5 +++++ >> 1 file changed, 5 insertions(+) >> >> diff --git a/arch/arm/boot/dts/rk3288.dtsi b/arch/arm/boot/dts/rk3288.dtsi >> index 2f814ffeb605..94f4b7eecca2 100644 >> --- a/arch/arm/boot/dts/rk3288.dtsi >> +++ b/arch/arm/boot/dts/rk3288.dtsi >> @@ -1075,6 +1075,11 @@ >> }; >> }; >> }; >> + >> + i2c-bus { >> + #address-cells = <1>; >> + #size-cells = <0>; >> + }; >> }; >> >> hdmi: hdmi@ff980000 { >