Re: [PATCH 2/5] arm64, thunder: Add initial dts for Cavium Thunder SoC

From: Mark Rutland <mark.rutland@arm.com>
To: Rob Herring <robherring2@gmail.com>
Cc: Robert Richter <rric@kernel.org>,
	Catalin Marinas <Catalin.Marinas@arm.com>,
	Will Deacon <Will.Deacon@arm.com>,
	Rob Herring <robh+dt@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
	Pawel Moll <Pawel.Moll@arm.com>,
	Ian Campbell <ijc+devicetree@hellion.org.uk>,
	Kumar Gala <galak@codeaurora.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	Radha Mohan Chintakuntla <rchintakuntla@cavium.com>,
	Robert Richter <rrichter@cavium.com>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>
Subject: Re: [PATCH 2/5] arm64, thunder: Add initial dts for Cavium Thunder SoC
Date: Wed, 30 Jul 2014 18:48:03 +0100	[thread overview]
Message-ID: <20140730174803.GF20162@leverpostej> (raw)
In-Reply-To: <CAL_JsqLJ_W34XTF2aMOW9z+Gq4oxbrX1RztyJN8Mi0OFPeNxfg@mail.gmail.com>

[...]

> >> +     gic0: interrupt-controller@801000000000 {
> >
> > To make this easier to read, please place a comma between 32-bit
> > portions of the unit address (e.g. here have 8010,00000000).
> 
> Mark, perhaps a dtc or checkpatch.pl check for this?

Sure. Dodgy first atttempt at checkpatch below.

---->8----

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 182be0f..8aee3f5 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2136,6 +2136,14 @@ sub process {
                        }
                }
 
+# check for difficult-to-read unit-addresses
+               if (defined $root &&
+                       ($realfile =~ /\.dtsi?$/ && $line =~ /([a-z0-9._\-+]++@([0-9a-f]+))\s*{/gi) &&
+                       (length($2) > 8)) {
+                               WARN("LONG_DT_UNIT_ADDRESS",
+                                    "Consider splitting long unit address \"$2\" with a comma between cells\n" . $herecurr);
+               }
+
 # check we are in a valid source file if not then ignore this hunk
                next if ($realfile !~ /\.(h|c|s|S|pl|sh)$/);
----8<----

It would also be nice to check matching unit-address and reg, but doing
that correctly requires knowing #address-cells, which sounds a little
painful.

I'm not sure where I picked up the comma convention, as it doesn't seem
to be in ePAPR.  It does seem common though, and is my personal
preference:

[mark@leverpostej:~/src/linux]% git grep '@[a-z0-9]\+,[a-b0-9]\+' \                          
	-- arch/arm/boot/dts | wc -l
254
[mark@leverpostej:~/src/linux]% git grep '@[a-z0-9]\+,[a-b0-9]\+' \
	-- arch/powerpc/boot/dts | wc -l
370
[mark@leverpostej:~/src/linux]% git grep '@[a-z0-9]\+,[a-b0-9]\+' \
        -- arch/*/boot/dts | wc -l
631

[...]

> >> +             uaa0: serial@87e024000000 {
> >> +                     compatible = "arm,pl011", "arm,primecell";
> >> +                     reg = <0x87e0 0x24000000 0x0 0x1000>;
> >> +                     interrupts = <1 21 4>;
> >> +                     clocks = <&refclk50mhz>;
> >> +                     clock-names = "apb_pclk";
> >
> > Is this actually the apb_pclk, or is the the uartclk? I assume it's the
> > latter.
> 
> Shouldn't new bindings have both clocks here? A single clock was a
> mistake I think (mine in fact).

I don't think we fixed it up in the end. It made drivers look a bit messy and
it dropped off my priority queue.

Cheers,
Mark.
