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:
 <PH0PR03MB69387FA17AE40D62115E29B88E5A2@PH0PR03MB6938.namprd03.prod.outlook.com>
Date: Wed, 13 Nov 2024 05:45:30 +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: Friday, November 8, 2024 10:31 PM
> 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 11/7/24 23:44, Encarnacion, Cedric justine wrote:
> >> -----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
> 
> We use the same driver for many variants of ltc2978. We should do the same
> here.
> 
> > 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?
> >
> 
> Succeeding version, but please synchronize with the engineer adding support
> for adp1055 to the adp1050 driver. Another option would be to make adding
> support
> for adp1051/adp1055 and adding support for ltp880X chips a patch series. The
> introductory patch could then reference the original patch series.
> 
> Thanks,
> Guenter

I coordinated with the engineer adding support for ADP1051/ADP1055. We will
be submitting a new patch series adding support for ADP1051, ADP1055 and
LTP8800-XX with reference to the original patch series.

Regards,
Cedric