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

From: Guenter Roeck <linux@roeck-us.net>
To: Robert Marko <robert.marko@sartura.hr>
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 07:27:21 -0700	[thread overview]
Message-ID: <5a11415f-4c0f-b073-6325-2e9b4078655c@roeck-us.net> (raw)
In-Reply-To: <CA+HBbNHQrZRcz-3qBn1RkqLxOn_+sNH8VKJVihkaaiFoAy=d7g@mail.gmail.com>

On 5/21/21 5:33 AM, Robert Marko wrote:
> 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.

Ok, thanks. Guess we'll have to live with that.

>>
>> 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.

Hmm, it seems more likely that the field is empty. Block read
isn't really different from other read operations.

Thanks,
Guenter

>>
>> 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
> 
> 
> 