Re: [PATCH v2 1/1] hwmon: (pmbus) Add regulator supply into macro

[Zev Weiss]

On Tue, Feb 22, 2022 at 08:51:04AM PST, Guenter Roeck wrote:
> On Mon, Feb 21, 2022 at 12:09:56PM +0100, Marcello Sylvester Bauer wrote:
> > Add regulator supply into PWBUS_REGULATOR macro. This makes it optional
> > to define a vin-supply in DT. Not defining a supply will add a dummy
> > regulator supply instead and only cause the following debug output:
> >
> > ```
> > Looking up vin-supply property in node [...] failed
> > ```
> >
> > Signed-off-by: Marcello Sylvester Bauer <sylv@xxxxxxx>
>
> Applied to hwmon-next. That should give it some time to mature,
> and we can pull or modify it if it causes any problems.

Wish I'd caught this sooner, but unfortunately I've just discovered that 
this does in fact cause breakage on my systems -- having regulator-dummy 
set as a supply on my PMBus regulators (instead of having them as their 
own top-level regulators without an upstream supply) leads to 
enable-count underflow errors when disabling them:

    # echo 0 > /sys/bus/platform/devices/efuse01/state
    [  906.094477] regulator-dummy: Underflow of regulator enable count
    [  906.100563] Failed to disable vout: -EINVAL
    [  136.992676] reg-userspace-consumer efuse01: Failed to configure state: -22

A simple revert solves the problem for me, but since I'm honestly a 
little unclear on the intent of the patch itself I'm not sure what a 
revert might break and hence I don't know if that's necessarily the 
right fix.  Marcello (or others), any thoughts?


Thanks,
Zev