From: Doug Anderson <dianders@chromium.org>
To: Mark Brown <broonie@kernel.org>
Cc: Marco Felsch <m.felsch@pengutronix.de>,
Chunyan Zhang <zhang.chunyan@linaro.org>,
Liam Girdwood <lgirdwood@gmail.com>,
ckeepax@opensource.cirrus.com,
LKML <linux-kernel@vger.kernel.org>,
Sascha Hauer <kernel@pengutronix.de>
Subject: Re: [PATCH 1/3] regulator: core: fix boot-on regulators use_count usage
Date: Mon, 23 Sep 2019 15:40:09 -0700 [thread overview]
Message-ID: <CAD=FV=VkaXDn034EFnJWYvWwyLgvq7ajfgMRm9mbhQeRKmPDRQ@mail.gmail.com> (raw)
In-Reply-To: <20190923184907.GY2036@sirena.org.uk>
Hi,
On Mon, Sep 23, 2019 at 11:49 AM Mark Brown <broonie@kernel.org> wrote:
>
> On Mon, Sep 23, 2019 at 11:36:11AM -0700, Doug Anderson wrote:
> > On Mon, Sep 23, 2019 at 11:14 AM Mark Brown <broonie@kernel.org> wrote:
>
> > > Boot on means that it's powered on when the kernel starts, it's
> > > for regulators that we can't read back the status of.
>
> > 1. Would it be valid to say that it's always incorrect to set this
> > property if there is a way to read the status back from the regulator?
>
> As originally intended, yes. I'm now not 100% sure that it won't
> break any existing systems though :/
Should I change the bindings doc to say that?
> > 2. Would this be a valid description of how the property is expected to behave
> > a) At early boot this regulator will be turned on if it wasn't already on.
> > b) If no clients are found for this regulator after everything has
> > loaded, this regulator will be automatically disabled.
>
> > If so then I don't _think_ #2b is happening, but I haven't confirmed.
>
> > > boot-on just refers to the status at boot, we can still turn
> > > those regulators off later on if we want to.
>
> > How, exactly? As of my commit 5451781dadf8 ("regulator: core: Only
> > count load for enabled consumers") if you do:
>
> > r = regulator_get(...)
> > regulator_disable(r)
>
> > ...then you'll get "Underflow of regulator enable count". In other
> > words, if a given regulator client disables more times than it enables
> > then you will get an error. Since there is no client that did the
> > initial "boot" enable then there's no way to do the disable unless it
> > happens automatically (as per 2b above).
>
> It should be possible to do a regulator_disable() though I'm not
> sure anyone actually uses that. The pattern for a regular
> consumer should be the normal enable/disable pair to handle
> shared usage, only an exclusive consumer should be able to use
> just a straight disable.
Ah, I see, I wasn't aware of the "exclusive" special case! Marco: is
this working for you? I wonder if we need to match
"regulator->enable_count" to "rdev->use_count" at the end of
_regulator_get() in the exclusive case...
-Doug
next prev parent reply other threads:[~2019-09-23 22:40 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-17 15:40 [PATCH 0/3] Regulator core fixes Marco Felsch
2019-09-17 15:40 ` [PATCH 1/3] regulator: core: fix boot-on regulators use_count usage Marco Felsch
2019-09-23 18:02 ` Doug Anderson
2019-09-23 18:14 ` Mark Brown
2019-09-23 18:36 ` Doug Anderson
2019-09-23 18:49 ` Mark Brown
2019-09-23 22:40 ` Doug Anderson [this message]
2019-09-24 18:27 ` Mark Brown
2019-09-26 19:44 ` Doug Anderson
2019-09-27 8:47 ` Marco Felsch
2019-10-01 19:57 ` Doug Anderson
2019-10-04 6:34 ` Matti Vaittinen
2019-10-04 11:32 ` Mark Brown
2019-10-04 12:03 ` Vaittinen, Matti
2019-10-04 15:01 ` Mark Brown
2019-10-07 9:34 ` Marco Felsch
2019-10-07 18:29 ` Mark Brown
2019-10-08 6:03 ` Marco Felsch
2019-10-08 12:51 ` Mark Brown
2019-10-08 14:56 ` Marco Felsch
2019-10-08 15:42 ` Mark Brown
2019-10-08 16:16 ` Marco Felsch
2019-10-08 16:23 ` Mark Brown
2019-10-08 20:16 ` Marco Felsch
2019-10-09 9:54 ` Mark Brown
2019-09-17 15:40 ` [PATCH 2/3] regulator: of: fix suspend-min/max-voltage parsing Marco Felsch
2019-09-17 16:02 ` Applied "regulator: of: fix suspend-min/max-voltage parsing" to the regulator tree Mark Brown
2019-09-17 15:40 ` [PATCH 3/3] regulator: core: make regulator_register() EPROBE_DEFER aware Marco Felsch
2019-09-17 16:02 ` Applied "regulator: core: make regulator_register() EPROBE_DEFER aware" to the regulator tree Mark Brown
2019-09-18 0:57 ` [PATCH 3/3] regulator: core: make regulator_register() EPROBE_DEFER aware Dmitry Torokhov
2019-09-18 8:18 ` Marco Felsch
2019-09-18 15:53 ` Dmitry Torokhov
2019-09-18 16:06 ` Marco Felsch
2019-09-18 16:08 ` Mark Brown
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAD=FV=VkaXDn034EFnJWYvWwyLgvq7ajfgMRm9mbhQeRKmPDRQ@mail.gmail.com' \
--to=dianders@chromium.org \
--cc=broonie@kernel.org \
--cc=ckeepax@opensource.cirrus.com \
--cc=kernel@pengutronix.de \
--cc=lgirdwood@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=m.felsch@pengutronix.de \
--cc=zhang.chunyan@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).