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Date: Tue, 27 Oct 2015 17:39:35 -0700
From: Brian Norris <computersforpeace@gmail.com>
To: Ray Jui <rjui@broadcom.com>
Cc: Anup Patel <anup.patel@broadcom.com>,
        David Woodhouse <dwmw2@infradead.org>,
        Linux MTD <linux-mtd@lists.infradead.org>,
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        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>, Sudeep Holla <sudeep.holla@arm.com>,
        Ian Campbell <ijc+devicetree@hellion.org.uk>,
        Kumar Gala <galak@codeaurora.org>,
        Scott Branden <sbranden@broadcom.com>,
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        Pramod KUMAR <pramodku@broadcom.com>,
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Subject: Re: [PATCH v3 2/2] arm64: dts: Add BRCM IPROC NAND DT node for NS2
Message-ID: <20151028003935.GZ13239@google.com>
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On Tue, Oct 27, 2015 at 05:25:32PM -0700, Ray Jui wrote:
> On 10/27/2015 5:19 PM, Brian Norris wrote:
> >On Fri, Oct 23, 2015 at 10:46:13AM +0530, Anup Patel wrote:
> >>diff --git a/arch/arm64/boot/dts/broadcom/ns2.dtsi b/arch/arm64/boot/dts/broadcom/ns2.dtsi
> >>index f603277..9610822 100644
> >>--- a/arch/arm64/boot/dts/broadcom/ns2.dtsi
> >>+++ b/arch/arm64/boot/dts/broadcom/ns2.dtsi
> >>@@ -212,5 +212,19 @@
> >>  			compatible = "brcm,iproc-rng200";
> >>  			reg = <0x66220000 0x28>;
> >>  		};
> >>+
> >>+		nand: nand@66460000 {
> >>+			compatible = "brcm,nand-iproc", "brcm,brcmnand-v6.1";
> >
> >Technically, the binding says you should also have "brcm,brcmnand" as a
> >last resort. Otherwise (for the NAND parts):
> >
> 
> I believe Anup was seeing issues when both "brcm,nand-iproc" and
> "brcm,brcmnand" are present.
> 
> Note "brcm,nand-iproc" invokes 'iproc_nand_probe', which calls
> 'brcmnand_probe' in the end.
> 
> "brcm,brcmnand" invokes 'brcmstb_nand_probe', which also calls
> 'brcmstb_probe', but without all the prep configuration required for
> "brcm,nand-iproc".

Ah, I forgot about that problem. That seems like an OF infrastructure
issue that could be fixed. We could lump these drivers back together,
and make sure that "brcm,nand-iproc" gets the priority in the
of_device_id list.

Or we could just relax the DT binding.

But wait, wouldn't cygnus already have that problem? You're using the
binding I suggested in arch/arm/boot/dts/bcm-cygnus.dtsi.

Oh, and I see we hacked this one in drivers/mtd/nand/brcmnand/Makefile:

  # link order matters; don't link the more generic brcmstb_nand.o before the
  # more specific iproc_nand.o, for instance

Brian