From:   Michael Walle <michael@walle.cc>
To:     zajec5@gmail.com
Cc:     devicetree@vger.kernel.org, hayashi.kunihiko@socionext.com,
        krzysztof.kozlowski+dt@linaro.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-mediatek@lists.infradead.org, matthias.bgg@gmail.com,
        mhiramat@kernel.org, rafal@milecki.pl, robh+dt@kernel.org,
        srinivas.kandagatla@linaro.org, Michael Walle <michael@walle.cc>
Subject: Re: [PATCH 3/4] nvmem: mtk-efuse: replace driver with a generic MMIO one
Date:   Wed,  1 Feb 2023 09:48:21 +0100
Message-Id: <20230201084821.1719839-1-michael@walle.cc>
In-Reply-To: <20230201064717.18410-4-zajec5@gmail.com>
References: <20230201064717.18410-4-zajec5@gmail.com>
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> From: Rafał Miłecki <rafal@milecki.pl>
> 
> Mediatek EFUSE uses a simple MMIO that can be handled with a generic
> driver. Replace this driver to avoid code duplication.

I don't think this is the correct approach. You'll restrict that driver
to being read-only. I admit that right now, it's read only, but it can
be extended to also support efuse writing. With this changes, it's not
possible.

> static const struct of_device_id mmio_nvmem_of_match_table[] = {
> 	{ .compatible = "mmio-nvmem", },
>+	/* Custom bindings that were introduced before the mmio one */
>+	{ .compatible = "mediatek,mt8173-efuse", },
>+	{ .compatible = "mediatek,efuse", },

Why do you assume that all mediatek efuses will be the same? This should
rather be something like (in the dts/binding):

compatible = "mediatek,mt8173-efuse", "mmio-nvmem";

So if there is no driver for the particular efuse, it will fall back to the
generic one.

-michael