Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754616AbbHXNrX (ORCPT ); Mon, 24 Aug 2015 09:47:23 -0400 Received: from mail-yk0-f179.google.com ([209.85.160.179]:34916 "EHLO mail-yk0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754264AbbHXNrU (ORCPT ); Mon, 24 Aug 2015 09:47:20 -0400 MIME-Version: 1.0 In-Reply-To: <874mjxwyx5.fsf@eliezer.anholt.net> References: <1439427380-2436-1-git-send-email-eric@anholt.net> <1439427380-2436-2-git-send-email-eric@anholt.net> <55CEC25E.7070303@wwwdotorg.org> <874mjxwyx5.fsf@eliezer.anholt.net> From: Rob Herring Date: Mon, 24 Aug 2015 08:47:00 -0500 Message-ID: Subject: Re: [PATCH 1/7] drm/vc4: Add devicetree bindings for VC4. To: Eric Anholt Cc: Stephen Warren , dri-devel , "devicetree@vger.kernel.org" , Lee Jones , linux-rpi-kernel@lists.infradead.org, "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2298 Lines: 46 On Mon, Aug 17, 2015 at 1:30 PM, Eric Anholt wrote: > Stephen Warren writes: > >> On 08/12/2015 06:56 PM, Eric Anholt wrote: >>> Signed-off-by: Eric Anholt >> >> This one definitely needs a patch description, since someone might not >> know what a VC4 is, and "git log" won't show the text from the binding >> doc itself. I'd suggest adding the initial paragraph of the binding doc >> as the patch description, or more. >> >>> diff --git a/Documentation/devicetree/bindings/gpu/brcm,bcm-vc4.txt b/Documentation/devicetree/bindings/gpu/brcm,bcm-vc4.txt > >>> +- hvss: List of references to HVS video scalers >>> +- encoders: List of references to output encoders (HDMI, SDTV) >> >> Would it make sense to make all those nodes child node of the vc4 >> object. That way, there's no need to have these lists of objects; they >> can be automatically built up as the DT is enumerated. I know that e.g. >> the NVIDIA Tegra host1x binding works this way, and I think it may have >> been inspired by other similar cases. > > I've looked at tegra, and the component system used by msm appears to be > nicer than it. To follow tegra's model, it looks like I need to build > this extra bus thing corresponding to host1x that is effectively the > drivers/base/component.c code, so that I can get at vc4's structure from > the component drivers. > >> Of course, this is only appropriate if the HW modules really are >> logically children of the VC4 HW module. Perhaps they aren't. If they >> aren't though, I wonder what this "vc4" module actually represents in HW? > > It's the subsystem, same as we use a subsystem node for msm, sti, > rockchip, imx, and exynos. This appears to be the common model of how > the collection of graphics-related components is represented in the DT. I think most of these bindings are wrong. They are grouped together because that is what DRM wants not because that reflects the h/w. So convince me this is one block, not that it is what other people do. Rob -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/