linux-kernel - Re: [PATCH v3 0/2] hwmon: (tps23861) add class restrictions and semi-auto mode support

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Message-ID: <4e7a2570-41ec-4179-96b2-f8550181afd9@roeck-us.net>
Date: Sun, 7 Sep 2025 09:06:25 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: gfuchedgi@...il.com, Robert Marko <robert.marko@...tura.hr>,
 Luka Perkov <luka.perkov@...tura.hr>, Jean Delvare <jdelvare@...e.com>,
 Jonathan Corbet <corbet@....net>, Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>
Cc: linux-hwmon@...r.kernel.org, linux-doc@...r.kernel.org,
 linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
 Oleksij Rempel <o.rempel@...gutronix.de>,
 Kory Maincent <kory.maincent@...tlin.com>,
 Network Development <netdev@...r.kernel.org>
Subject: Re: [PATCH v3 0/2] hwmon: (tps23861) add class restrictions and
 semi-auto mode support

+Cc: pse-pd maintainers and netdev mailing list

On 9/4/25 10:33, Gregory Fuchedgi via B4 Relay wrote:
> This patch series introduces per-port device tree configuration with poe
> class restrictions. Also adds optional reset/shutdown gpios.
> 
> Tested with hw poe tester:
>   - Auto mode tested with no per-port DT settings as well as explicit port
>     DT ti,class=4. Tested that no IRQ is required in this case.
>   - Semi-Auto mode with class restricted to 0, 1, 2 or 3. IRQ required.
>   - Tested current cut-offs in Semi-Auto mode.
>   - On/off by default setting tested for both Auto and Semi-Auto modes.
>   - Tested fully disabling the ports in DT.
>   - Tested with both reset and ti,ports-shutdown gpios defined, as well as
>     with reset only, as well as with neither reset nor shutdown.
> 
> Signed-off-by: Gregory Fuchedgi <gfuchedgi@...il.com>

This entire series makes me more and more unhappy. It is not the responsibility
of the hardware monitoring subsystem to control power. The hardware monitoring
subsystem is for monitoring, not for control.

Please consider adding a driver for this chip to the pse-pd subsystem
(drivers/net/pse-pd). As it turns out, that subsystem already supports
tps23881. This is a similar chip which even has a similar register set.

This driver could then be modified to be an auxiliary driver of that driver.
Alternatively, we could drop this driver entirely since the pse-pd subsystem
registers the chips it supports as regulator which has its own means to handle
telemetry.

Thanks,
Guenter