From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tobias Jakobi Subject: Re: exynos4412: porting hdmiddc and hdmiphy node entries Date: Mon, 05 May 2014 22:55:53 +0200 Message-ID: <5367FAD9.9080705@gmx.net> References: <535C504A.2090809@gmx.net> <53675932.30306@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mout.gmx.net ([212.227.15.18]:55188 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755604AbaEEUz7 (ORCPT ); Mon, 5 May 2014 16:55:59 -0400 In-Reply-To: <53675932.30306@samsung.com> Sender: linux-samsung-soc-owner@vger.kernel.org List-Id: linux-samsung-soc@vger.kernel.org To: Tomasz Stanislawski , linux-samsung-soc@vger.kernel.org Hello Tomasz, thanks a lot for the support! > The meaning of hdmiphy is ambiguous. > In exynos4 spec there are _TWO_ components named HDMIPHY. > The first one is a PLL that generates a clock for HDMI subsystem. > This PLL is controlled by I2C. > > You can find an example of its bindings at: > http://lists.freedesktop.org/archives/dri-devel/2013-October/047687.html OK, that looks exactly like the bindings I currently have in the dts. > The second one is HDMI's physical interface located in PMU unit. > > The exynos-simple-phy is dedicated to controller the former (component of PMU). > > The 'phy' attribute in DT refers to the PLL. > There is a debate if 'phy' should refer to I2C device itself or > rather to I2C bus. Currently it refers to driverless instance > of I2C device. By 'driverless' you mean that the node isn't probed by any specific driver code / the 'compatible' string isn't used anywhere in the kernel (like it's currently the situation?) >> Somehow this doesn't look right. And indeed: >> https://patchwork.kernel.org/patch/4021121/ >> >> At least for exynos5250 this node is not a child on an i2c adapter. > > This is a completely different HDMIPHY. I'm not sure I understand. Different from the PPL and the PMU HDMIPHY? >> And yes, I would still have to add 'phys' and 'phy-names' to the hdmi >> node. This looks wrong again. Why do I have to specify 'phys' when I >> already have 'phy' there? Isn't that redundant? > > 'phys' and 'phy-names' refers to PHY interfaces delivered by phy-core. > The attribute named 'phy' refers to I2C device used to controller HDMI's PLL. > The naming convention is very misleading. Hmm, indeed this is very confusing. So with the move to exynos-simple-phy, I guess I need these entries as well, am I correct? >> Well, you see, lots of confusion here. I would appreciate any kind of >> help on how to proceed here. > > The documentation for HDMI's bindings should be fixed. Well, I can agree with that :) With best wishes, Tobias