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

[Nuno Sá]

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.

- Nuno Sá