Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Tue, 17 Aug 2021 14:58:00 -0500
From:   Rob Herring <robh@kernel.org>
To:     Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc:     Joakim Zhang <qiangqing.zhang@nxp.com>, shawnguo@kernel.org,
        kernel@pengutronix.de, linux-imx@nxp.com,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH V1 1/4] bindings: nvmem: introduce "reverse-data" property
Message-ID: <YRwUyLsvoSpFI9X8@robh.at.kernel.org>
References: <20210810073510.18218-1-qiangqing.zhang@nxp.com>
 <20210810073510.18218-2-qiangqing.zhang@nxp.com>
 <6e3f6881-929d-1663-58f1-39bf35069175@linaro.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <6e3f6881-929d-1663-58f1-39bf35069175@linaro.org>
Precedence: bulk

On Wed, Aug 11, 2021 at 11:16:49AM +0100, Srinivas Kandagatla wrote:
> 
> 
> On 10/08/2021 08:35, Joakim Zhang wrote:
> > Introduce "reverse-data" property for nvmem provider to reverse buffer.
> > 
> > Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
> > ---
> >   Documentation/devicetree/bindings/nvmem/nvmem.yaml | 5 +++++
> >   1 file changed, 5 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/nvmem/nvmem.yaml b/Documentation/devicetree/bindings/nvmem/nvmem.yaml
> > index b8dc3d2b6e92..bc745083fc64 100644
> > --- a/Documentation/devicetree/bindings/nvmem/nvmem.yaml
> > +++ b/Documentation/devicetree/bindings/nvmem/nvmem.yaml
> > @@ -61,6 +61,11 @@ patternProperties:
> >                 description:
> >                   Size in bit within the address range specified by reg.
> > +      reverse-data:
> > +        $ref: /schemas/types.yaml#/definitions/flag
> > +        description:
> > +          Reverse the data that read from the storage device.
> > +
> 
> This new property is only going to solve one of the reverse order issue
> here.
> If I remember correctly we have mac-address stored in various formats ex:
> from old thread I can see
> 
> Type 1: Octets in ASCII without delimiters. (Swapped/non-Swapped)
> Type 2: Octets in ASCII with delimiters like (":", ",", ".", "-"... so on)
> (Swapped/non-Swapped)
> Type 3: Is the one which stores mac address in Type1/2 but this has to be
> incremented to be used on other instances of eth.
> Type 4: Octets as bytes/u8, swapped/non-swapped
> 
> I think its right time to consider adding compatibles to nvmem-cells to be
> able to specify encoding information and handle post processing.

Yes. Trying to handle this with never ending new properties will end up 
with a mess. At some point, you just need code to parse the data.

Rob