Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934255AbcJTNqN (ORCPT ); Thu, 20 Oct 2016 09:46:13 -0400 Received: from gloria.sntech.de ([95.129.55.99]:46915 "EHLO gloria.sntech.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933094AbcJTNqL (ORCPT ); Thu, 20 Oct 2016 09:46:11 -0400 From: Heiko =?ISO-8859-1?Q?St=FCbner?= To: Tomeu Vizoso , Rob Herring , Mark Rutland 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 Subject: Re: [PATCH] ARM: dts: rockchip: add i2c-bus subnode to edp Date: Thu, 20 Oct 2016 15:45:34 +0200 Message-ID: <7604646.6yosK0XMNL@diego> User-Agent: KMail/4.14.10 (Linux/4.6.0-1-amd64; KDE/4.14.22; x86_64; ; ) In-Reply-To: <1476950845-28242-1-git-send-email-tomeu.vizoso@collabora.com> References: <1476950845-28242-1-git-send-email-tomeu.vizoso@collabora.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1674 Lines: 52 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? 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 {