linux-kernel - Re: [PATCH v3 2/3] arm64: dts: renesas: draak: Describe CVBS input

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Message-ID: <1728709.thk7gXDxlo@avalon>
Date:   Mon, 21 May 2018 16:10:34 +0300
From:   Laurent Pinchart <laurent.pinchart@...asonboard.com>
To:     jacopo mondi <jacopo@...ndi.org>
Cc:     Jacopo Mondi <jacopo+renesas@...ndi.org>,
        niklas.soderlund@...natech.se, horms@...ge.net.au, geert@...der.be,
        magnus.damm@...il.com, robh+dt@...nel.org,
        linux-renesas-soc@...r.kernel.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/3] arm64: dts: renesas: draak: Describe CVBS input

Hi Jacopo,

On Monday, 21 May 2018 15:33:40 EEST jacopo mondi wrote:
> On Mon, May 21, 2018 at 01:54:55PM +0300, Laurent Pinchart wrote:
> > On Monday, 21 May 2018 12:57:05 EEST jacopo mondi wrote:
> >> On Fri, May 18, 2018 at 06:12:15PM +0300, Laurent Pinchart wrote:
> >>> On Friday, 18 May 2018 17:47:57 EEST Jacopo Mondi wrote:
> >>>> Describe CVBS video input through analog video decoder ADV7180
> >>>> connected to video input interface VIN4.
> >>>> 
> >>>> The video input signal path is shared with HDMI video input, and
> >>>> selected by on-board switches SW-53 and SW-54 with CVBS input
> >>>> selected by the default switches configuration.
> >>>> 
> >>>> Signed-off-by: Jacopo Mondi <jacopo+renesas@...ndi.org>
> >>>> Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@...natech.se>
> >>>> 
> >>>> ---
> >>>> v2 -> v3:
> >>>> - Add comment to describe the shared input video path
> >>>> - Add my SoB and Niklas' R-b tags
> >>>> ---
> >>>> 
> >>>>  arch/arm64/boot/dts/renesas/r8a77995-draak.dts | 42 ++++++++++++++++++
> >>>>  1 file changed, 42 insertions(+)
> >>>> 
> >>>> diff --git a/arch/arm64/boot/dts/renesas/r8a77995-draak.dts
> >>>> b/arch/arm64/boot/dts/renesas/r8a77995-draak.dts index
> >>>> 9d73de8..95745fc
> >>>> 100644
> >>>> --- a/arch/arm64/boot/dts/renesas/r8a77995-draak.dts
> >>>> +++ b/arch/arm64/boot/dts/renesas/r8a77995-draak.dts
> >>>> @@ -142,6 +142,11 @@
> >>>>  		groups = "usb0";
> >>>>  		function = "usb0";
> >>>>  	};
> >>>> +
> >>>> +	vin4_pins_cvbs: vin4 {
> >>>> +		groups = "vin4_data8", "vin4_sync", "vin4_clk";
> >>>> +		function = "vin4";
> >>>> +	};
> >>>>  };
> >>>>  
> >>>>  &i2c0 {
> >>>> @@ -154,6 +159,23 @@
> >>>>  		reg = <0x50>;
> >>>>  		pagesize = <8>;
> >>>>  	};
> >>>> +
> >>>> +	analog-video@20 {
> >>>> +		compatible = "adi,adv7180";
> >>>> +		reg = <0x20>;
> >>>> +
> >>>> +		port {
> >>> 
> >>> The adv7180 DT bindings document the output port as 3 or 6
> >>> (respectively for the CP and ST versions of the chip). You should thus
> >>> number the port. Apart from that the patch looks good.
> >> 
> >> I admit I have barely copied this from Gen-2 boards DTS, but reading
> >> the driver code and binding description again, I think this is
> >> correct, as the output port numbering and mandatory input port (which
> >> is missing here) only apply to adv7180cp/st chip versions.
> >> 
> >> Here we describe plain adv7180, no need to number output ports afaict.
> > 
> > Indeed, my bad.
> > 
> > Shouldn't you however use "adi,adv7180cp" as that's the chip we are using
> > ?
> > The "adi,adv7180" has no port documented in its DT bindings, so it
> > shouldn't have any port node at all.
> 
> I'm a bit confused here.
> 
> The only Gen-2 board using the "adi,adv7180cp" compatible string is
> Gose, which is also the only one I can get schematics for. That board
> indeed feature an ADV7180WBCP32Z, as the Draak does. I cannot get
> schematics for any other Gen-2 board, to compare the ADV7180 variant
> installed there. If anyone can confirm that all other Gen-2 board uses
> a different version (or that all other Gen-2 board DTS file use a
> wrong compatible string value), I'll re-send this with a different
> compatible value and proper port nodes numbering.

Other Gen2 boards use a ADV7180WBCP32Z as well. The issue here isn't that the 
chip you're trying to support is different. The DT bindings that were 
initially written for the adi,adv7180 didn't have port nodes. When it was time 
to add them, we realized that two variants of the chip existed with different 
connectivity. We have thus added two new compatible strings to differentiate 
them, with different port numbers. The old compatible string should be 
deprecated in favour of the new ones.

> >>>> +			/*
> >>>> +			 * The VIN4 video input path is shared between
> >>>> +			 * CVBS and HDMI inputs through SW[49-54] switches.
> >>>> +			 *
> >>>> +			 * CVBS is the default selection, link it to VIN4 here.
> >>>> +			 */
> >>>> +			adv7180_out: endpoint {
> >>>> +				remote-endpoint = <&vin4_in>;
> >>>> +			};
> >>>> +		};
> >>>> +	};
> >>>>  };
> >>>>  
> >>>>  &i2c1 {
> >>>> @@ -246,3 +268,23 @@
> >>>>  	timeout-sec = <60>;
> >>>>  	status = "okay";
> >>>>  };
 >>>> +
> >>>> +&vin4 {
> >>>> +	pinctrl-0 = <&vin4_pins_cvbs>;
> >>>> +	pinctrl-names = "default";
> >>>> +
> >>>> +	status = "okay";
> >>>> +
> >>>> +	ports {
> >>>> +		#address-cells = <1>;
> >>>> +		#size-cells = <0>;
> >>>> +
> >>>> +		port@0 {
> >>>> +			reg = <0>;
> >>>> +
> >>>> +			vin4_in: endpoint {
> >>>> +				remote-endpoint = <&adv7180_out>;
> >>>> +			};
> >>>> +		};
> >>>> +	};
> >>>> +};

-- 
Regards,

Laurent Pinchart