From: Zev Weiss <zev@bewilderbeest.net>
To: linux-kernel@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Arnd Bergmann <arnd@arndb.de>
Cc: Zev Weiss <zev@bewilderbeest.net>,
openbmc@lists.ozlabs.org, Rob Herring <robh+dt@kernel.org>,
Guenter Roeck <linux@roeck-us.net>,
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: [PATCH 0/4] misc: Add power-efuse driver
Date: Thu, 17 Feb 2022 02:44:40 -0800 [thread overview]
Message-ID: <20220217104444.7695-1-zev@bewilderbeest.net> (raw)
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.
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
--
2.35.1
next reply other threads:[~2022-02-17 10:46 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-17 10:44 Zev Weiss [this message]
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 ` [PATCH 0/4] " Guenter Roeck
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