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Date: Thu, 6 Jun 2024 13:05:32 +0100
From: Mark Brown <broonie@kernel.org>
To: Prabhakar <prabhakar.csengg@gmail.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>,
	Ulf Hansson <ulf.hansson@linaro.org>, Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Wolfram Sang <wsa+renesas@sang-engineering.com>,
	Liam Girdwood <lgirdwood@gmail.com>,
	Magnus Damm <magnus.damm@gmail.com>, linux-mmc@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-renesas-soc@vger.kernel.org,
	Fabrizio Castro <fabrizio.castro.jz@renesas.com>,
	Biju Das <biju.das.jz@bp.renesas.com>,
	Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Subject: Re: [RFC PATCH 1/4] regulator: core: Ensure the cached state matches
 the hardware state in regulator_set_voltage_unlocked()
Message-ID: <22664e29-4c7a-4544-ad32-25c3d7e342e9@sirena.org.uk>
References: <20240605074936.578687-1-prabhakar.mahadev-lad.rj@bp.renesas.com>
 <20240605074936.578687-2-prabhakar.mahadev-lad.rj@bp.renesas.com>
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On Wed, Jun 05, 2024 at 08:49:33AM +0100, Prabhakar wrote:

> Driver code flow:
> 1> set regulator to 1.8V (BIT0 = 1)
> 2> Regulator cached state now will be 1.8V
> 3> Now for some reason driver issues a reset to the IP block
>    which resets the registers to default value. In this process
>    the regulator is set to 3.3V (BIT0 = 0)
> 4> Now the driver requests the regulator core to set 1.8V

If something is resetting the regulator like this that's a problem in
general, we need to either have the driver notify the core when that
happens so it can reconfigure the regulator or have it reapply
configuration directly.  Obviously it's not great to have that happen at
all...

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