Re: [PATCH 2/2] hwmon: (pmbus) Add driver for Analog Devices MAX20912 and MAX20916

[Nuno Sá]

On Tue, Jul 07, 2026 at 06:52:48AM -0700, Guenter Roeck wrote:
> On 7/7/26 05:26, Fred Chen wrote:
> > Add support for the Analog Devices MAX20912 and MAX20916 dual-output
> > multiphase voltage regulators with PMBus interfaces.
> > 
> > Signed-off-by: Fred Chen <fredchen.openbmc@xxxxxxxxx>
> 
> Please provide evidence that those chips actually exist.
> Internet search comes up blank. I'll need confirmation
> from someone at Analog.

Hi Guenter,

Well, in fact I'm in the middle of preparing a series that adds support
for:

"max20826"
"max20855b"
"max20908"
"max20912"
"max20916"

All the above parts have the datasheet under NDA. But before we had a
one page "datasheet" in analog.com but I guess that is gone! For context
I mainly did the base (core) driver for max20826 and then Alexis added
the other ones.

Not sure how to proceed... I can wait and then work on top of what Fred
has but this patch is very minimal when compared with what we have.
Like:

* No regulator support;
* No direct mode. The chip has two ways to access registers (paging and
* direct mode).
* No way to count how many phases we have or if RAIL_B (func[1]) is being used at
all.


Some other things more intriguing is that these chips, as far as I'm
aware (at least for max20826), always have bit 2 set in ON_OFF_CONFIG so
a gpio vout. Also we needed some special handling to read phase current
which I'm not seeing in the driver. So I would like to understand how
the chip was tested?

Anyways, if Fred is ok with it I can just finish what I'm doing and send
the patches. It would make sense to have something more complete on
submission but I don't want to just "steal" the work already done.

- Nuno Sá

> 
> Thanks,
> Guenter
>