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@xxxxxxxxxxxxxxxxxxxxxxxx/ [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
