From mboxrd@z Thu Jan 1 00:00:00 1970 From: Krzysztof Kozlowski Subject: Re: [PATCH v3 06/14] Documentation: drm/bridge: add document for analogix_dp Date: Tue, 25 Aug 2015 10:35:19 +0900 Message-ID: <55DBC657.6060409@samsung.com> References: <1439995728-18046-1-git-send-email-ykk@rock-chips.com> <1439995834-18363-1-git-send-email-ykk@rock-chips.com> <55DA8486.1000803@rock-chips.com> <55DA9B72.1030804@samsung.com> <55DB1281.9070502@rock-chips.com> <55DBAD90.3040901@samsung.com> <55DBC601.5090107@rock-chips.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-reply-to: <55DBC601.5090107@rock-chips.com> Sender: linux-kernel-owner@vger.kernel.org To: Yakir Yang , Rob Herring Cc: heiko@sntech.de, Sean Paul , Takashi Iwai , dri-devel , Andrzej Hajda , Gustavo Padovan , "linux-samsung-soc@vger.kernel.org" , Vincent Palatin , Kishon Vijay Abraham I , linux-rockchip@lists.infradead.org, Russell King , Thierry Reding , "devicetree@vger.kernel.org" , Pawel Moll , Ian Campbell , David Airlie , Doug Anderson , Inki Dae , Ajay kumar , Rob Herring , "linux-arm-kernel@lists.infradead.org" M List-Id: devicetree@vger.kernel.org On 25.08.2015 10:33, Yakir Yang wrote: > Hi Krzysztof, >=20 > =E5=9C=A8 2015/8/25 7:49, Krzysztof Kozlowski =E5=86=99=E9=81=93: >> On 24.08.2015 21:48, Yakir Yang wrote: >>> Hi Krzysztof, >>> >>> =E5=9C=A8 08/24/2015 12:20 PM, Krzysztof Kozlowski =E5=86=99=E9=81=93= : >>>> On 24.08.2015 11:42, Yakir Yang wrote: >>>>> Hi Krzysztof, >>>>> >>>>> =E5=9C=A8 08/23/2015 07:43 PM, Krzysztof Kozlowski =E5=86=99=E9=81= =93: >>>>>> 2015-08-24 8:23 GMT+09:00 Rob Herring : >>>>>>> On Wed, Aug 19, 2015 at 9:50 AM, Yakir Yang >>>>>>> wrote: >>>>>>>> Analogix dp driver is split from exynos dp driver, so we just >>>>>>>> make an copy of exynos_dp.txt, and then simplify exynos_dp.txt >>>>>>>> >>>>>>>> Beside update some exynos dtsi file with the latest change >>>>>>>> according to the devicetree binding documents. >>>>>>> You can't just change the exynos bindings and break >>>>>>> compatibility. Is >>>>>>> there some agreement with exynos folks to do this? >>>>>> No, there is no agreement. This wasn't even sent to Exynos >>>>>> maintainers. >>>>> Sorry about this one, actually I have add Exynos maintainers in >>>>> version >>>>> 1 & version 2, >>>>> but lose some maintainers in version 3, I would fix it in bellow >>>>> versions. >>>>> >>>>>> Additionally the patchset did not look interesting to me because= of >>>>>> misleading subject - Documentation instead of "ARM: dts:". >>>>>> >>>>>> Yakir, please: >>>>>> 1. Provide backward compatibility. Mark old properties as deprec= ated >>>>>> but still support them. >>>>> Do you mean that I should keep the old properties declare in >>>>> exynos-dp.txt, >>>>> but just mark them as deprecated flag. >>>> That is one of ways how to do this. However more important is that >>>> driver should still support old bindings so such code: >>>> - if (of_property_read_u32(dp_node, "samsung,color-space", >>>> + if (of_property_read_u32(dp_node, "analogix,color-space", >>>> >>>> is probably wrong. Will the driver support old DTB in the same way >>>> as it >>>> was supporting before the change? >>> Okay, I got your means. So document is not the focus, the most impo= rtant >>> is that >>> driver should support the old dts prop. >> Right, the focus is on the driver. >> >>> If so the new analogix dp driver >>> should keep >>> the "samsung,color-space", rather then just mark it with [DEPRECATE= D] >>> flag. >> If you are replacing a binding/property then it should be marked >> deprecated. This means that the old property is still working but ne= w >> users of it should not be added. >=20 > Okay, so just quote Heiko's reply, such code would be need in analogi= x > dp driver. >=20 > if (of_property_read_u32(dp_node, "analogix,color-space", > &dp_video_config->color_space)) > if (of_property_read_u32(dp_node, "samsung,color-space", > &dp_video_config->color_space)) = { >=20 > dev_err(dev, "failed to get color-space\n"); > return ERR_PTR(-EINVAL); > } Yes. It does not look pretty but something like this is needed. Best regards, Krzysztof