From mboxrd@z Thu Jan 1 00:00:00 1970 From: Philipp Zabel Subject: Re: [RFC resend 1/4] dt-bindings: display: mediatek: add drm binding Date: Thu, 19 Oct 2017 15:06:37 +0200 Message-ID: <1508418397.7665.18.camel@pengutronix.de> References: <20171019112610.13645-1-mbrugger@suse.com> <20171019112610.13645-2-mbrugger@suse.com> <8477650.BPhWpTmuMS@avalon> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <8477650.BPhWpTmuMS@avalon> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Laurent Pinchart , Matthias Brugger Cc: ulrich.hecht+renesas-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, ck.hu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org, airlied-cv59FeDIM0c@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, linux-I+IVW8TIWO2tmTQ+vhA3Yw@public.gmane.org, catalin.marinas-5wv7dgnIgG8@public.gmane.org, will.deacon-5wv7dgnIgG8@public.gmane.org, dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-mediatek-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Matthias Brugger List-Id: devicetree@vger.kernel.org On Thu, 2017-10-19 at 15:53 +0300, Laurent Pinchart wrote: > Hi Matthias, > > Thank you for the patch. > > On Thursday, 19 October 2017 14:26:07 EEST Matthias Brugger wrote: > > DRM subysystem and clock driver shared the same compatible mmsys. > > This stopped does not work, as only the first driver for a compatible > > gets probed. We change the comaptible to the new DRM identifier to fix > > this. > > > > Signed-off-by: Matthias Brugger > > --- > > .../devicetree/bindings/display/mediatek/mediatek,disp.txt | 6 +++ > > 1 file changed, 6 insertions(+) > > > > diff --git > > a/Documentation/devicetree/bindings/display/mediatek/mediatek,disp.txt > > b/Documentation/devicetree/bindings/display/mediatek/mediatek,disp.txt > > index 383183a89164..6db652463e64 100644 > > --- a/Documentation/devicetree/bindings/display/mediatek/mediatek,disp.txt > > +++ b/Documentation/devicetree/bindings/display/mediatek/mediatek,disp.txt > > @@ -27,6 +27,7 @@ > > Documentation/devicetree/bindings/display/mediatek/mediatek,dpi.txt. > > > > Required properties (all function blocks): > > - compatible: "mediatek,-disp-", one of > > + "mediatek,-dispsys" - central component for the DRM system > > "mediatek,-disp-ovl" - overlay (4 layers, blending, csc) > > "mediatek,-disp-rdma" - read DMA / line buffer > > "mediatek,-disp-wdma" - write DMA > > @@ -71,6 +72,11 @@ mmsys: clock-controller@14000000 { > > #clock-cells = <1>; > > }; > > > > +dispsys: display-system { > > + compatible = "mediatek,mt2701-dispsys"; > > + mediatek,mmsys = <&mmsys>; > > +} > > So this node doesn't correspond to an IP core but is meant as a top-level > entry point for the operating system. This leads me to three questions. > > 1. Is there any IP core in the Mediatek display subsystem that could be > considered (or at least used) as a top-level entry point ? That would be my > preferred solution as I'm not fond of DT nodes not describing hardware. At least on MT8173 that node is MMSYS, which it is currently matching against. The issue, if I understand correctly, is that the clocks provided by this same region were previously created via CLK_OF_DECLARE, and are now changed to a separate clock driver that matches to the same node. > 2. If there's no such IP core, are all the display subsystem IP cores grouped > together in one MMIO register range ? If so we could move them as children of > this new display system node which, even if doesn't describe an IP core, would > describe the way the display IP cores are grouped in the hardware, and would > thus be a hardware description. > > 3. If the answer to the second question is also negative, shouldn't this > display system node reference all other display IP DT nodes (through direct > phandles and/or OF graph bindings) ? > > > ovl0: ovl@1400c000 { > > compatible = "mediatek,mt8173-disp-ovl"; > > reg = <0 0x1400c000 0 0x1000>; > regards Philipp -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html