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Date: Fri, 5 Apr 2024 08:31:37 +0200
From: Andreas Kemnade <andreas@kemnade.info>
To: Matti Vaittinen <mazziesaccount@gmail.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>, lee@kernel.org,
 robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
 devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] dt-bindings: mfd: Add ROHM BD71879
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On Fri, 5 Apr 2024 09:01:25 +0300
Matti Vaittinen <mazziesaccount@gmail.com> wrote:

> > Yes. If there are reasons against, please briefly mention them in commit
> > msg.  
> 
> I would like to understand the rationale for allowing:
> compatible = "rohm,bd71879", "rohm,bd71828".
> 
> Is the intention to:
> 1) allow boards which tell the software that "the hardware may be 
> bd71828 or bd71879", or
> 2) to tell a binding reader that these ICs are likely to be usable as 
> replacements to each others?
> (Or, is there some other rationale beyond these?)

As far as I understand the second compatible can be a fallback for
software which does not know the bd71879 (remember the devicetree is
not only for linux). Especially if that software does not use the full
functionality of the device, like drivers in bootloaders do. E.g.
mmc drivers in bootloaders might not use high speed modes at all, so
differences in them do not matter.

Regards,
Andreas