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

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Date:   Fri, 4 Nov 2022 16:42:50 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Zev Weiss <zev@...ilderbeest.net>
Cc:     Marcello Sylvester Bauer <sylv@...v.io>,
        Jean Delvare <jdelvare@...e.com>, linux-kernel@...r.kernel.org,
        linux-hwmon@...r.kernel.org,
        Patrick Rudolph <patrick.rudolph@...ements.com>
Subject: Re: [PATCH v2 1/1] hwmon: (pmbus) Add regulator supply into macro

On Fri, Nov 04, 2022 at 03:30:30PM -0700, Zev Weiss wrote:
> 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@...v.io>
> > 
> > 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?

Revert now, ask questions later. I'll send a patch.

Guenter

> 
> 
> Thanks,
> Zev
>