From: Guenter Roeck <linux@roeck-us.net>
To: Zev Weiss <zev@bewilderbeest.net>,
linux-kernel@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Arnd Bergmann <arnd@arndb.de>
Cc: openbmc@lists.ozlabs.org, Rob Herring <robh+dt@kernel.org>,
Jean Delvare <jdelvare@suse.com>,
devicetree@vger.kernel.org, linux-hwmon@vger.kernel.org,
Mark Brown <broonie@kernel.org>,
Liam Girdwood <lgirdwood@gmail.com>
Subject: Re: [PATCH 0/4] misc: Add power-efuse driver
Date: Thu, 17 Feb 2022 10:14:18 -0800 [thread overview]
Message-ID: <5b0b69cf-5688-3679-dd77-49179e0b17bb@roeck-us.net> (raw)
In-Reply-To: <20220217104444.7695-1-zev@bewilderbeest.net>
On 2/17/22 02:44, Zev Weiss wrote:
> Hello,
>
> This patch series is another incarnation of some previous efforts [0]
> at enabling userspace access to the OPERATION state (and now status
> flags) of PMBus devices, specifically with respect to efuses
> protecting general-purpose power outputs. This functionality is an
> important component enabling a port of OpenBMC to the Delta AHE-50DC
> Open19 power shelf [1].
>
> The first patch extends the pmbus core's regulator support with an
> implementation of the .get_error_flags() operation, mapping PMBus
> status flags to REGULATOR_ERROR_* flags where possible, and the second
> patch adds regulator support for the lm25066 driver. These two
> patches are essentially independent of the power-efuse driver (and
> each other) and could potentially be applicable individually, but are
> necessary for the power-efuse driver to be useful on the AHE-50DC.
>
Nevertheless, the first two patches are orthogonal to the remaining
two patches and should be separate.
Guenter
> The third and fourth patches add dt-bindings and the implementation of
> the power-efuse driver, respectively. The driver is fairly simple; it
> merely provides a sysfs interface to enable, disable, and retrieve
> error flags from an underlying regulator.
>
> There is one aspect of its usage of the regulator API I'm a bit
> uncertain about, however: this driver seems like a case where an
> exclusive 'get' of the regulator (i.e. devm_regulator_get_exclusive()
> instead of devm_regulator_get() in efuse_probe()) would be
> appropriate, since in the intended usage no other device should be
> using an efuse's regulator. With an exclusive get though, the
> regulator's use_count and the consumer's enable_count don't balance
> out properly to allow the enable/disable operations to work properly
> (the former ending up one more than the latter, leading to
> enable_count underflows on attempts to disable the regulator). So at
> least for now it's using a non-exclusive get -- I'd be happy to hear
> any pointers on a way to allow an exclusive get to work here, though.
>
>
> Thanks,
> Zev
>
> [0] https://lore.kernel.org/openbmc/YGLepYLvtlO6Ikzs@hatter.bewilderbeest.net/
> [1] https://www.open19.org/marketplace/delta-16kw-power-shelf/
>
> Zev Weiss (4):
> hwmon: (pmbus) Add get_error_flags support to regulator ops
> hwmon: (pmbus) lm25066: Add regulator support
> dt-bindings: Add power-efuse binding
> misc: Add power-efuse driver
>
> .../devicetree/bindings/misc/power-efuse.yaml | 37 +++
> MAINTAINERS | 5 +
> drivers/hwmon/pmbus/Kconfig | 7 +
> drivers/hwmon/pmbus/lm25066.c | 14 ++
> drivers/hwmon/pmbus/pmbus_core.c | 97 ++++++++
> drivers/misc/Kconfig | 15 ++
> drivers/misc/Makefile | 1 +
> drivers/misc/power-efuse.c | 221 ++++++++++++++++++
> 8 files changed, 397 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/misc/power-efuse.yaml
> create mode 100644 drivers/misc/power-efuse.c
>
prev parent reply other threads:[~2022-02-17 18:14 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-17 10:44 [PATCH 0/4] misc: Add power-efuse driver Zev Weiss
2022-02-17 10:44 ` [PATCH 1/4] hwmon: (pmbus) Add get_error_flags support to regulator ops Zev Weiss
2022-02-17 18:11 ` Guenter Roeck
2022-02-17 23:37 ` Zev Weiss
2022-02-18 0:02 ` Guenter Roeck
2022-02-18 0:23 ` Zev Weiss
2022-02-17 10:44 ` [PATCH 2/4] hwmon: (pmbus) lm25066: Add regulator support Zev Weiss
2022-02-17 10:44 ` [PATCH 3/4] dt-bindings: Add power-efuse binding Zev Weiss
2022-02-17 16:39 ` Rob Herring
2022-02-17 22:35 ` Rob Herring
2022-02-18 0:17 ` Zev Weiss
2022-02-17 10:44 ` [PATCH 4/4] misc: Add power-efuse driver Zev Weiss
2022-02-17 13:34 ` Greg Kroah-Hartman
2022-02-17 22:53 ` Zev Weiss
2022-02-17 18:14 ` Guenter Roeck [this message]
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=5b0b69cf-5688-3679-dd77-49179e0b17bb@roeck-us.net \
--to=linux@roeck-us.net \
--cc=arnd@arndb.de \
--cc=broonie@kernel.org \
--cc=devicetree@vger.kernel.org \
--cc=gregkh@linuxfoundation.org \
--cc=jdelvare@suse.com \
--cc=lgirdwood@gmail.com \
--cc=linux-hwmon@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=openbmc@lists.ozlabs.org \
--cc=robh+dt@kernel.org \
--cc=zev@bewilderbeest.net \
/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).