From mboxrd@z Thu Jan 1 00:00:00 1970 From: Inki Dae Subject: RE: [PATCH 1/4] drm/exynos: rename compatible strings for hdmi subsystem Date: Wed, 19 Jun 2013 17:27:08 +0900 Message-ID: <00a001ce6cc6$ca1807e0$5e4817a0$%dae@samsung.com> References: <1371559778-9359-1-git-send-email-rahul.sharma@samsung.com> <1371559778-9359-2-git-send-email-rahul.sharma@samsung.com> <7536863.RugNVV3dBS@flatron> <1371628750.4230.3.camel@weser.hi.pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: In-reply-to: <1371628750.4230.3.camel@weser.hi.pengutronix.de> Content-language: ko Sender: linux-samsung-soc-owner@vger.kernel.org To: 'Lucas Stach' , 'Tomasz Figa' Cc: kgene.kim@samsung.com, devicetree-discuss@lists.ozlabs.org, sw0312.kim@samsung.com, joshi@samsung.com, dri-devel@lists.freedesktop.org, linux-samsung-soc@vger.kernel.org, rob.herring@calxeda.com, s.nawrocki@samsung.com, grant.likely@linaro.org, 'Rahul Sharma' List-Id: devicetree@vger.kernel.org > -----Original Message----- > From: dri-devel-bounces+inki.dae=samsung.com@lists.freedesktop.org > [mailto:dri-devel-bounces+inki.dae=samsung.com@lists.freedesktop.org] On > Behalf Of Lucas Stach > Sent: Wednesday, June 19, 2013 4:59 PM > To: Tomasz Figa > Cc: kgene.kim@samsung.com; devicetree-discuss@lists.ozlabs.org; > sw0312.kim@samsung.com; joshi@samsung.com; dri-devel@lists.freedesktop.org; > linux-samsung-soc@vger.kernel.org; rob.herring@calxeda.com; > s.nawrocki@samsung.com; grant.likely@linaro.org; Rahul Sharma > Subject: Re: [PATCH 1/4] drm/exynos: rename compatible strings for hdmi > subsystem > > Am Mittwoch, den 19.06.2013, 09:52 +0200 schrieb Tomasz Figa: > > Hi Rahul, > > > > On Tuesday 18 of June 2013 18:19:35 Rahul Sharma wrote: > > > This patch renames the combatible strings for hdmi, mixer, ddc > > > and hdmiphy. It follows the convention of using compatible string > > > which represent the SoC in which the IP was added for the first > > > time. > > > > > > Signed-off-by: Rahul Sharma > > > --- > > > Documentation/devicetree/bindings/video/exynos_hdmi.txt | 6 > > > ++++-- Documentation/devicetree/bindings/video/exynos_hdmiddc.txt | > > > 4 ++-- Documentation/devicetree/bindings/video/exynos_hdmiphy.txt | > > > 6 ++++-- Documentation/devicetree/bindings/video/exynos_mixer.txt | > > > 7 +++++-- drivers/gpu/drm/exynos/exynos_ddc.c | > > > 2 +- drivers/gpu/drm/exynos/exynos_hdmi.c | > > > 2 +- drivers/gpu/drm/exynos/exynos_hdmiphy.c | 4 > > > +++- drivers/gpu/drm/exynos/exynos_mixer.c | 12 > > > ++++++------ 8 files changed, 26 insertions(+), 17 deletions(-) > > > > > > diff --git a/Documentation/devicetree/bindings/video/exynos_hdmi.txt > > > b/Documentation/devicetree/bindings/video/exynos_hdmi.txt index > > > 589edee..2ac01ca 100644 > > > --- a/Documentation/devicetree/bindings/video/exynos_hdmi.txt > > > +++ b/Documentation/devicetree/bindings/video/exynos_hdmi.txt > > > @@ -1,7 +1,9 @@ > > > Device-Tree bindings for drm hdmi driver > > > > > > Required properties: > > > -- compatible: value should be "samsung,exynos5-hdmi". > > > +- compatible: value should be one among the following: > > > + 1) "samsung,exynos4210-hdmi" > > > + 2) "samsung,exynos4212-hdmi" > > > - reg: physical base address of the hdmi and length of memory mapped > > > region. > > > - interrupts: interrupt number to the cpu. > > > @@ -15,7 +17,7 @@ Required properties: > > > Example: > > > > > > hdmi { > > > - compatible = "samsung,exynos5-hdmi"; > > > + compatible = "samsung,exynos4212-hdmi"; > > > > Sorry, but it's a NAK from me. > > > > DeviceTree bindings are considered an ABI. This is to allow older dtbs > to > > work with new kernels. > > > > If you just change the binding this way, you break all the existing > users > > of this compatible value. > > > > In addition you are doing it in a way that breaks bisection: > > - patch 1/4 breaks existing in-tree users of current compatible values, > > - after patch 2 and 3 it is still broken, > > - and eventually all in-tree users are fixed by patch 4 (but you can't > > fix out-of-tree users). > > > > Please do it without changing existing compatible values. Even if they > are > > misleading, this is all can be described in the documentation - just > list > > SoCs that can be used with each compatible value there. > > > > Or you could just introduce the new compatible value and make all > in-tree users use this, but keep the old values around and still accept > them in the drivers. This way you get the goodness of the cleaner new > symbols without breaking existing users. Just mark the old values as > deprecated in the documentation, so no new devicetree usees them. > That's a good idea. We really need to mitigate such misleading somehow or other. Thanks, Inki Dae > Regards, > Lucas > -- > Pengutronix e.K. | Lucas Stach | > Industrial Linux Solutions | http://www.pengutronix.de/ | > Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-5076 | > Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/dri-devel