Message-ID: <c17f94a6-c710-f80e-c2af-9e450f144157@collabora.com>
Date:   Fri, 24 Feb 2023 14:13:59 +0100
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Subject: Re: [PATCH V2] nvmem: add explicit config option to read OF fixed
 cells
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To:     =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= <zajec5@gmail.com>,
        Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
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        Vignesh Raghavendra <vigneshr@ti.com>,
        Hector Martin <marcan@marcan.st>,
        Sven Peter <sven@svenpeter.dev>,
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        Neil Armstrong <neil.armstrong@linaro.org>,
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        Jerome Brunet <jbrunet@baylibre.com>,
        Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
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        =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= <rafal@milecki.pl>
References: <20230224072903.20945-1-zajec5@gmail.com>
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>
In-Reply-To: <20230224072903.20945-1-zajec5@gmail.com>
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Il 24/02/23 08:29, Rafał Miłecki ha scritto:
> From: Rafał Miłecki <rafal@milecki.pl>
> 
> NVMEM subsystem looks for fixed NVMEM cells (specified in DT) by
> default. This behaviour made sense in early days before adding support
> for dynamic cells.
> 
> With every new supported NVMEM device with dynamic cells current
> behaviour becomes non-optimal. It results in unneeded iterating over DT
> nodes and may result in false discovery of cells (depending on used DT
> properties).
> 
> This behaviour has actually caused a problem already with the MTD
> subsystem. MTD subpartitions were incorrectly treated as NVMEM cells.
> 
> Also with upcoming support for NVMEM layouts no new binding or driver
> should support fixed cells defined in device node.
> 
> Solve this by modifying drivers for bindings that support specifying
> fixed NVMEM cells in DT. Make them explicitly tell NVMEM subsystem to
> read cells from DT.
> 
> It wasn't clear (to me) if rtc and w1 code actually uses fixed cells. I
> enabled them to don't risk any breakage.
> 
> Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
> [for drivers/nvmem/meson-{efuse,mx-efuse}.c]
> Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>

[for mtk-efuse.c, nvmem/core.c, nvmem-provider.h]
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

[MT8192, MT8195 Chromebooks]
Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>