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Date:   Sun, 28 Aug 2022 16:42:07 +0200
From:   Michael Walle <michael@walle.cc>
To:     =?UTF-8?Q?Rafa=C5=82_Mi=C5=82ecki?= <rafal@milecki.pl>
Cc:     Miquel Raynal <miquel.raynal@bootlin.com>,
        Richard Weinberger <richard@nod.at>,
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        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
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        "David S . Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
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        netdev@vger.kernel.org, Ahmad Fatoum <a.fatoum@pengutronix.de>
Subject: Re: [RFC PATCH v1 12/14] nvmem: layouts: rewrite the u-boot-env
 driver as a NVMEM layout
In-Reply-To: <f830543b-9b66-5785-60f8-27ea05d49eee@milecki.pl>
References: <20220825214423.903672-1-michael@walle.cc>
 <20220825214423.903672-13-michael@walle.cc>
 <f830543b-9b66-5785-60f8-27ea05d49eee@milecki.pl>
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Am 2022-08-28 16:04, schrieb Rafał Miłecki:
> On 25.08.2022 23:44, Michael Walle wrote:
>> Instead of hardcoding the underlying access method mtd_read() and
>> duplicating all the error handling, rewrite the driver as a nvmem
>> layout which just uses nvmem_device_read() and thus works with any
>> NVMEM device.
>> 
>> But because this is now not a device anymore, the compatible string
>> will have to be changed so the device will still be probed:
>>    compatible = "u-boot,env";
>> to
>>    compatible = "u-boot,env", "nvmem-cells";
>> 
>> "nvmem-cells" will tell the mtd layer to register a nvmem_device().
>> "u-boot,env" will tell the NVMEM that it should apply the u-boot
>> environment layout to the NVMEM device.
> 
> That's fishy but maybe we can ignore backward compatibility at
> point.

As mentioned in the cover letter, this is why this is an RFC. I
didn't see any users in the device tree, nor can I see how this
would have been used anyway, because you cannot find a cell by
its device tree node, because none is registered. So maybe we
can still change the compatible string.

-michael

> Still you need to update DT binding.