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Message-ID: <c6d886d9-8f74-7af3-5478-030f5d6e4b1c@linaro.org>
Date:   Wed, 31 May 2023 21:27:02 +0200
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Subject: Re: [PATCH v2 1/2] dt-bindings: clock: Add nvmem-clock
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To:     Mike Looijmans <mike.looijmans@topic.nl>,
        devicetree@vger.kernel.org, linux-clk@vger.kernel.org
Cc:     Conor Dooley <conor+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Michael Turquette <mturquette@baylibre.com>,
        Rob Herring <robh+dt@kernel.org>,
        Stephen Boyd <sboyd@kernel.org>, linux-kernel@vger.kernel.org
References: <1b153bce-a66a-45ee-a5c6-963ea6fb1c82.949ef384-8293-46b8-903f-40a477c056ae.2167d5ad-7e99-4eb9-a313-030fc7a7d546@emailsignatures365.codetwo.com>
 <20230526143807.10164-1-mike.looijmans@topic.nl>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <20230526143807.10164-1-mike.looijmans@topic.nl>
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On 26/05/2023 16:38, Mike Looijmans wrote:
> Add bindings for a fixed-rate clock that retrieves its rate from an
> NVMEM provider. This allows to store clock settings in EEPROM or EFUSE
> or similar device.
> 
> Component shortages lead to boards being shipped with different clock
> crystals, based on what was available at the time. The clock frequency
> was written to EEPROM at production time. Systems can adapt to a wide
> range of input frequencies using the clock framework, but this required
> us to patch the devicetree at runtime or use some custom driver. This
> provides a more generic solution.

This does not look like real hardware. I mean, the clock does not fetch
its rate from nvmem, right? It's the Linux which does it, so basically
you described here driver, not hardware.

Extend existing fixed-clock bindings to allow reading frequency via
nvmem cells.


Best regards,
Krzysztof