linux-kernel - Re: [PATCH v4 1/2] mfd: tps65219: Implement LOCK register handling for TPS65214

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Message-ID: <20251113104215.7da3b846@kmaincent-XPS-13-7390>
Date: Thu, 13 Nov 2025 10:42:15 +0100
From: Kory Maincent <kory.maincent@...tlin.com>
To: Andrew Davis <afd@...com>
Cc: Aaro Koskinen <aaro.koskinen@....fi>, Andreas Kemnade
 <andreas@...nade.info>, Kevin Hilman <khilman@...libre.com>, Roger Quadros
 <rogerq@...nel.org>, Tony Lindgren <tony@...mide.com>, Lee Jones
 <lee@...nel.org>, Shree Ramamoorthy <s-ramamoorthy@...com>, Rob Herring
 <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>, Bajjuri Praneeth <praneeth@...com>, Thomas Petazzoni
 <thomas.petazzoni@...tlin.com>, <linux-omap@...r.kernel.org>,
 <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
 <stable@...r.kernel.org>
Subject: Re: [PATCH v4 1/2] mfd: tps65219: Implement LOCK register handling
 for TPS65214

On Wed, 12 Nov 2025 13:03:22 -0600
Andrew Davis <afd@...com> wrote:

> On 11/12/25 9:14 AM, Kory Maincent (TI.com) wrote:
> > The TPS65214 PMIC variant has a LOCK_REG register that prevents writes to
> > nearly all registers when locked. Unlock the registers at probe time and
> > leave them unlocked permanently.
> > 
> > This approach is justified because:
> > - Register locking is very uncommon in typical system operation
> > - No code path is expected to lock the registers during runtime  
> 
> Any other entity in the system that could re-lock these registers?
> How about low power modes or other PM handling?

No there is no reason to re-lock these registers. It will be locked again only
if the PMIC is reset.
In any case, if one case appears that needs to lock these register (even
if I think it is unlikely) we could come back to the regmap custom write
design. 

Regards,
-- 
Köry Maincent, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com