+ linux-hwmon@xxxxxxxxxxxxxxx On Mon, Jun 29, 2020 at 08:31:11AM +0200, zlukwins wrote: > Hi, > > > I am OpenBMC FW developer working currently on some power measurement stuff. > > I would like to have maximum rated input power for pmubus device available > in hwmon sysfs. This value is read by MFR_PIN_MAX command: > > /MFR_PIN_MAX// > //The MFR_PIN_MIN command sets or retrieves the maximum rated value, in > watts, of// > //the input power./ Interesting typo in the PMBus specification. Yes, it really does associate MFR_PIN_MIN - which doesn't seem to exist - with the maximum rated output power. > > And I wondering which attribute shell be used to expose that value in sysfs. > I went through documentation > (https://www.kernel.org/doc/Documentation/hwmon/sysfs-interface) and found > the following: > > power[1-*]_max Maximum power. > Unit: microWatt > RW > > But it looks like it is already occupied by PIN_OP_WARN_LIMIT. > > Maybe new attribute shall be used? If so how to call that? > None of the standard attributes reports (or is supposed to report) rated values, so we can not just use any of those. Also, we can not just add a single attribute to handle this situation, for the simple reason that there are many more similar attributes. PMBus specifies (this is from version 1.3.1): MFR_VIN_MIN MFR_VIN_MAX MFR_IIN_MAX MFR_PIN_MAX MFR_VOUT_MIN MFR_VOUT_MAX MFR_IOUT_MAX MFR_POUT_MAX MFR_TAMBIENT_MAX MFR_TAMBIENT_MIN MFR_MAX_TEMP_{1,2.3} All those report rated values. I do see the need/desire for reporting such information. The only real solution I can see is to add a new set of attributes to the hwmon ABI. Something like: currentX_rated_min # for consistency currentX_rated_max inX_rated_min inX_rated_max powerX_rated_min # for consistency powerX_rated_max tempX_rated_min tempX_rated_max plus maybe, for consistency: humidityX_rated_min humidityX_rated_max Those would be read-only attributes. Thoughts, comments, feedback anyone ? Thanks, Guenter
