Re: [PATCH 1/3] hwmon: (pmbus) Add driver for Delta DPS-920AB PSU

From: Robert Marko <robert.marko@sartura.hr>
To: Guenter Roeck <linux@roeck-us.net>
Cc: jdelvare@suse.com, corbet@lwn.net, linux-hwmon@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	Luka Perkov <luka.perkov@sartura.hr>,
	jmp@epiphyte.org, Paul Menzel <pmenzel@molgen.mpg.de>,
	Donald Buczek <buczek@molgen.mpg.de>
Subject: Re: [PATCH 1/3] hwmon: (pmbus) Add driver for Delta DPS-920AB PSU
Date: Fri, 21 May 2021 14:33:39 +0200	[thread overview]
Message-ID: <CA+HBbNHQrZRcz-3qBn1RkqLxOn_+sNH8VKJVihkaaiFoAy=d7g@mail.gmail.com> (raw)
In-Reply-To: <cfbe487f-8d01-e9b7-0aae-f93a27aff023@roeck-us.net>

On Fri, May 21, 2021 at 1:41 PM Guenter Roeck <linux@roeck-us.net> wrote:
>
> On 5/21/21 1:36 AM, Robert Marko wrote:
> [ ... ]
> >> In this context, I have a hard time finding a reference for
> >> this power supply. Do you have a datasheet or some other documents
> >> you can share ?
> >
> > Unfortunately, I don't have a datasheet as that would have made this way easier.
> > It was all based on the vendor "driver" from DENT:
> > https://github.com/dentproject/dentOS/blob/main/packages/platforms/delta/arm64/tn48m/tn48m-poe/modules/builds/src/arm64-delta-tn48m-poe-psu.c
> >
>
> Ah, so this is not a driver for a power supply from DeltaPSU,
> but a power supply from Delta Networks Technology Corporation,
> as used in that company's TN48M-POE switch. That is a world
> of difference, even though the parent company seems to be the
> same. I am not sure if, based on this information, the driver
> should claim to be for "Delta DPS-920AB PSU" in the first place.

It's actually a PSU from Delta Electronics INC, Delta Networks are just using
it inside of the Delta Networks TN48M-DN-P switch.
I checked the label on the PSU-s.
>
> Can you run a block read on MFR_MODEL and MFG_SERIAL ?
> That might give us an idea about the actual manufacturer
> and model of this power supply.

MFG_SERIAL is just a bunch of 0xf-s, but MFR_MODEL has something.
However, the Armada 7040 I2C adapter cannot do block reads although
it returns 11 bytes but it's just zeros.
>
> Also, isn't that the same power supply for which you were
> trying to add another hwmon driver to display some of its
> status information, obtained from some CPLD ?

This and one more as the non-PoE version of the TN48M-DN switch
has a single 150W PSU that does not support PMBus, but the CPLD
always provides presence information and Power Good status.
>
> Thanks,
> Guenter


-- 
Robert Marko
Staff Embedded Linux Engineer
Sartura Ltd.
Lendavska ulica 16a
10000 Zagreb, Croatia
Email: robert.marko@sartura.hr
Web: www.sartura.hr