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

[Torreno, Alexis Czezar]

> On 7/8/26 04:32, Nuno Sá wrote:
> > On Wed, Jul 08, 2026 at 12:50:25PM +0200, Krzysztof Kozlowski wrote:
> >> On Wed, Jul 08, 2026 at 10:19:56AM +0100, Nuno Sá wrote:
> >>> 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.
> >>
> >> Binding should be in such case posted complete, so probably not a
> >> trivial device.
> >
> > Yes, in my series bindings are not in trivial as we support the enable
> > gpios.
> >
> 
> Same question I asked before: What is your use case ?
> 

Hi Guenter,

Unlike my MAX20830 patches, for some reason these chips (not only Nuno's max20826)
hardwired the bit 2 in ON_OFF_CONFIG to '1'. This makes the use of gpio to enable the
device a requirement.  (as of the latest info given to us)

Regards,
Alexis