linux-kernel - Re: [PATCH RFC v4 07/13] regulator: find active protections during initialization

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Message-ID: <030a99f7-98f3-a24d-612c-d460859fc276@gmail.com>
Date:   Mon, 26 Jun 2023 16:56:21 +0300
From:   Matti Vaittinen <mazziesaccount@...il.com>
To:     Benjamin Bara <bbara93@...il.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>
Cc:     support.opensource@...semi.com,
        DLG-Adam.Ward.opensource@...renesas.com,
        Martin Fuzzey <martin.fuzzey@...wbird.group>,
        linux-kernel@...r.kernel.org,
        Benjamin Bara <benjamin.bara@...data.com>
Subject: Re: [PATCH RFC v4 07/13] regulator: find active protections during
 initialization

On 6/20/23 23:03, Benjamin Bara wrote:
> From: Benjamin Bara <benjamin.bara@...data.com>
> 
> It can happen that monitors are activated before the kernel is started,
> e.g. by bootloader or by OTP. If monitoring workarounds are active on a
> regulator, the core shouldn't perform the state changes without applying
> the workaround to the regulator. Therefore, warn the user already during
> initialization that the device-tree should be adapted.
> 
> Warning can be fixed by enabling (or disabling) monitoring in the DT,
> e.g.:
> regulator-uv-protection-microvolt = <1>;
> or
> regulator-ov-error-microvolt = <0>;
> 
> Constraints regarding the monitoring of a regulator can usually be found
> in the docu.

I am not entirely sure if this is the right thing to do. Should we 
expect the hardware state to be what is described in DT at Linux boot-up 
- or, should we silently accept the fact that for example boot can alter 
things.

 From the 'code pov' I have no complaints though. I just can't say if 
warning is the right idea. I'll leave this for bigger brains to decide :)


-- 
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

~~ When things go utterly wrong vim users can always type :help! ~~