linux-kernel - RE: [PATCH v2 2/2] hwmon: pmbus: add driver for ltp8800-1a, ltp8800-4a, and ltp8800-2

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Message-ID:
 <PH0PR03MB693869F52D961845C8388D258E5D2@PH0PR03MB6938.namprd03.prod.outlook.com>
Date: Fri, 8 Nov 2024 07:44:01 +0000
From: "Encarnacion, Cedric justine" <Cedricjustine.Encarnacion@...log.com>
To: Guenter Roeck <linux@...ck-us.net>,
        "devicetree@...r.kernel.org"
	<devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>,
        "linux-i2c@...r.kernel.org"
	<linux-i2c@...r.kernel.org>,
        "linux-doc@...r.kernel.org"
	<linux-doc@...r.kernel.org>,
        "linux-hwmon@...r.kernel.org"
	<linux-hwmon@...r.kernel.org>
CC: Jean Delvare <jdelvare@...e.com>, Jonathan Corbet <corbet@....net>,
        Delphine CC Chiu <Delphine_CC_Chiu@...ynn.com>,
        Rob Herring
	<robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley
	<conor+dt@...nel.org>,
        Peter Yin <peteryin.openbmc@...il.com>,
        Noah Wang
	<noahwang.wang@...look.com>, Marek Vasut <marex@...x.de>,
        Lukas Wunner
	<lukas@...ner.de>
Subject: RE: [PATCH v2 2/2] hwmon: pmbus: add driver for ltp8800-1a,
 ltp8800-4a, and ltp8800-2

> -----Original Message-----
> From: Guenter Roeck <groeck7@...il.com> On Behalf Of Guenter Roeck
> Sent: Thursday, November 7, 2024 9:45 AM
> To: Encarnacion, Cedric justine <Cedricjustine.Encarnacion@...log.com>;
> devicetree@...r.kernel.org; linux-kernel@...r.kernel.org; linux-
> i2c@...r.kernel.org; linux-doc@...r.kernel.org; linux-
> hwmon@...r.kernel.org
> Cc: Jean Delvare <jdelvare@...e.com>; Jonathan Corbet <corbet@....net>;
> Delphine CC Chiu <Delphine_CC_Chiu@...ynn.com>; Rob Herring
> <robh@...nel.org>; Krzysztof Kozlowski <krzk+dt@...nel.org>; Conor Dooley
> <conor+dt@...nel.org>; Peter Yin <peteryin.openbmc@...il.com>; Noah
> Wang <noahwang.wang@...look.com>; Marek Vasut <marex@...x.de>;
> Lukas Wunner <lukas@...ner.de>
> Subject: Re: [PATCH v2 2/2] hwmon: pmbus: add driver for ltp8800-1a,
> ltp8800-4a, and ltp8800-2
> 
> [External]
> 
> On 11/5/24 19:09, Cedric Encarnacion wrote:
> > LTP8800-1A 54V, 150A DC/DC µModule Regulator with PMBus Interface
> > LTP8800-4A 54V, 200A DC/DC µModule Regulator with PMBus Interface
> > LTP8800-2 54V, 135A DC/DC μModule Regulator with PMBus Interface
> >
> > The LTP8800 is a family of step-down μModule regulators that provides
> > microprocessor core voltage from 54V power distribution architecture. It
> > features telemetry monitoring of input/output voltage, input current,
> > output power, and temperature over PMBus.
> >
> > Signed-off-by: Cedric Encarnacion <cedricjustine.encarnacion@...log.com>
> 
> Looking closer into the datasheets, I found that the PMBus commands are
> identical
> to those of ADP1055, and an extension of the ADP1050 driver to support
> ADP1055
> has been submitted.
> 
> With this in mind, please explain why this series warrants a new driver instead
> of just extending the existing driver to support LTP8800.

It also appears that the LTP8800-1A regulator makes use of
factory-programmed ADP1055 but this is not explicitly stated for other
variants. Initially, I thought a new client driver would be reasonable
since this device is intended as a regulator while ADP1050/ADP1055 is a
more customizable digital controller, and both have their own multiple
variants. Indeed, it may be more reasonable to extend existing driver since
they are exposing the same feature. In this case, can this be done in
succeeding version/s of this series?

Thank you, 
Cedric

> 
> Thanks,
> Guenter