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diff --git a/Documentation/hwmon/occ.rst b/Documentation/hwmon/occ.rst new file mode 100644 index 000000000000..bf41c162d70e --- /dev/null +++ b/Documentation/hwmon/occ.rst @@ -0,0 +1,153 @@ +Kernel driver occ-hwmon +======================= + +Supported chips: + + * POWER8 + * POWER9 + +Author: Eddie James <eajames@linux.ibm.com> + +Description +----------- + +This driver supports hardware monitoring for the On-Chip Controller (OCC) +embedded on POWER processors. The OCC is a device that collects and aggregates +sensor data from the processor and the system. The OCC can provide the raw +sensor data as well as perform thermal and power management on the system. + +The P8 version of this driver is a client driver of I2C. It may be probed +manually if an "ibm,p8-occ-hwmon" compatible device is found under the +appropriate I2C bus node in the device-tree. + +The P9 version of this driver is a client driver of the FSI-based OCC driver. +It will be probed automatically by the FSI-based OCC driver. + +Sysfs entries +------------- + +The following attributes are supported. All attributes are read-only unless +specified. + +The OCC sensor ID is an integer that represents the unique identifier of the +sensor with respect to the OCC. For example, a temperature sensor for the third +DIMM slot in the system may have a sensor ID of 7. This mapping is unavailable +to the device driver, which must therefore export the sensor ID as-is. + +Some entries are only present with certain OCC sensor versions or only on +certain OCCs in the system. The version number is not exported to the user +but can be inferred. + +temp[1-n]_label + OCC sensor ID. + +[with temperature sensor version 1] + + temp[1-n]_input + Measured temperature of the component in millidegrees + Celsius. + +[with temperature sensor version >= 2] + + temp[1-n]_type + The FRU (Field Replaceable Unit) type + (represented by an integer) for the component + that this sensor measures. + temp[1-n]_fault + Temperature sensor fault boolean; 1 to indicate + that a fault is present or 0 to indicate that + no fault is present. + + [with type == 3 (FRU type is VRM)] + + temp[1-n]_alarm + VRM temperature alarm boolean; 1 to indicate + alarm, 0 to indicate no alarm + + [else] + + temp[1-n]_input + Measured temperature of the component in + millidegrees Celsius. + +freq[1-n]_label + OCC sensor ID. +freq[1-n]_input + Measured frequency of the component in MHz. +power[1-n]_input + Latest measured power reading of the component in + microwatts. +power[1-n]_average + Average power of the component in microwatts. +power[1-n]_average_interval + The amount of time over which the power average + was taken in microseconds. + +[with power sensor version < 2] + + power[1-n]_label + OCC sensor ID. + +[with power sensor version >= 2] + + power[1-n]_label + OCC sensor ID + function ID + channel in the form + of a string, delimited by underscores, i.e. "0_15_1". + Both the function ID and channel are integers that + further identify the power sensor. + +[with power sensor version 0xa0] + + power[1-n]_label + OCC sensor ID + sensor type in the form of a string, + delimited by an underscore, i.e. "0_system". Sensor + type will be one of "system", "proc", "vdd" or "vdn". + For this sensor version, OCC sensor ID will be the same + for all power sensors. + +[present only on "master" OCC; represents the whole system power; only one of +this type of power sensor will be present] + + power[1-n]_label + "system" + power[1-n]_input + Latest system output power in microwatts. + power[1-n]_cap + Current system power cap in microwatts. + power[1-n]_cap_not_redundant + System power cap in microwatts when + there is not redundant power. + power[1-n]_cap_max + Maximum power cap that the OCC can enforce in + microwatts. + power[1-n]_cap_min Minimum power cap that the OCC can enforce in + microwatts. + power[1-n]_cap_user The power cap set by the user, in microwatts. + This attribute will return 0 if no user power + cap has been set. This attribute is read-write, + but writing any precision below watts will be + ignored, i.e. requesting a power cap of + 500900000 microwatts will result in a power cap + request of 500 watts. + + [with caps sensor version > 1] + + power[1-n]_cap_user_source + Indicates how the user power cap was + set. This is an integer that maps to + system or firmware components that can + set the user power cap. + +The following "extn" sensors are exported as a way for the OCC to provide data +that doesn't fit anywhere else. The meaning of these sensors is entirely +dependent on their data, and cannot be statically defined. + +extn[1-n]_label + ASCII ID or OCC sensor ID. +extn[1-n]_flags + This is one byte hexadecimal value. Bit 7 indicates the + type of the label attribute; 1 for sensor ID, 0 for + ASCII ID. Other bits are reserved. +extn[1-n]_input + 6 bytes of hexadecimal data, with a meaning defined by + the sensor ID. |