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Date:   Wed, 13 Mar 2019 14:12:31 +0100
From:   Miquel Raynal <miquel.raynal@bootlin.com>
To:     Paul Cercueil <paul@crapouillou.net>
Cc:     David Woodhouse <dwmw2@infradead.org>,
        Brian Norris <computersforpeace@gmail.com>,
        Boris Brezillon <bbrezillon@kernel.org>,
        Marek Vasut <marek.vasut@gmail.com>,
        Richard Weinberger <richard@nod.at>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Harvey Hunt <harveyhuntnexus@gmail.com>,
        linux-mtd@lists.infradead.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 2/9] dt-bindings: mtd: ingenic: Change 'BCH' to 'ECC'
 in documentation
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In-Reply-To: <1552481988.2412.2@crapouillou.net>
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        <1552481988.2412.2@crapouillou.net>
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Hi Paul,

Paul Cercueil <paul@crapouillou.net> wrote on Wed, 13 Mar 2019 09:59:48
-0300:

> Le lun. 4 mars 2019 à 15:58, Miquel Raynal <miquel.raynal@bootlin.com> a écrit :
> > Hi Paul,
> > 
> > Paul Cercueil <paul@crapouillou.net> wrote on Mon, 04 Mar 2019 > 19:23:50
> > +0100:
> >   
> >>  On Mon, Mar 4, 2019 at 10:50 AM, Miquel Raynal >> <miquel.raynal@bootlin.com> wrote:  
> >>  > Hi Paul,
> >>  >
> >>  > Paul Cercueil <paul@crapouillou.net >> <mailto:paul@crapouillou.net>> > wrote on Sat,  9 Feb 2019 16:22:58
> >>  > -0300:
> >>  >  
> >>  >>  The JZ4740 ECC hardware is not BCH but Reed-Solomon, so it >> makes >> more
> >>  >>  sense to use the more generic ECC term.  
> >>  >> >>  Signed-off-by: Paul Cercueil <paul@crapouillou.net >> >> <mailto:paul@crapouillou.net>>  
> >>  >>  ---  
> >>  >> >>  Changes:
> >>  >> >>  v3: New patch
> >>  >> >>  v4: No change
> >>  >> >>   .../devicetree/bindings/mtd/ingenic,jz4780-nand.txt    | 18 >> >> +++++++++---------  
> >>  >>   1 file changed, 9 insertions(+), 9 deletions(-)  
> >>  >> >>  diff --git >> >> a/Documentation/devicetree/bindings/mtd/ingenic,jz4780-nand.txt >> >> b/Documentation/devicetree/bindings/mtd/ingenic,jz4780-nand.txt  
> >>  >>  index a5b940f18bf6..5a45cc54f46d 100644  
> >>  >>  --- >> a/Documentation/devicetree/bindings/mtd/ingenic,jz4780-nand.txt  
> >>  >>  +++ >> b/Documentation/devicetree/bindings/mtd/ingenic,jz4780-nand.txt
> >>  >>  @@ -1,4 +1,4 @@
> >>  >>  -* Ingenic JZ4780 NAND/BCH
> >>  >>  +* Ingenic JZ4780 NAND/ECC  
> >>  >> >>   This file documents the device tree bindings for NAND flash >> >> devices on the  
> >>  >>   JZ4780. NAND devices are connected to the NEMC controller >> >> (described in
> >>  >>  @@ -14,10 +14,10 @@ Required NAND controller device properties:
> >>  >>     an offset of 0 and a size of 0x1000000 (i.e. the whole NEMC >> >> bank).  
> >>  >> >>   Optional NAND controller device properties:  
> >>  >>  -- ingenic,bch-controller: To make use of the hardware BCH >> >> controller, this
> >>  >>  -  property must contain a phandle for the BCH controller node. >> The >> required
> >>  >>  +- ingenic,bch-controller: To make use of the hardware ECC >> >> controller, this
> >>  >>  +  property must contain a phandle for the ECC controller node. >> The >> required  
> >>  >
> >>  > I think there is already a 'ecc-engine' property used by MTK and >> Atmel
> >>  > NAND controllers to point to the ECC engine block. Please use this
> >>  > property instead of the ingenic specific one.  
> >> >>  ingenic,bch-controller is already in the devicetree ABI. I can't >> change it now...  
> > 
> > Oh, right...
> > 
> > Well, same thing as before, maybe you can change it and keep the > driver
> > backward compatible? I don't want new DT to use this property because
> > it is not generic and we must have a way from the core to find the ECC
> > engine handle when the controller does not embed one itself (thus, the
> > ecc-engine property which is around for quite some time already).  
> 
> I can do that. Will the new ECC framework work with the "ecc-engine" property?

Yes.

Right now it does not, but when supporting raw NAND devices, it will
have to.


Thanks,
Miquèl