ibmaem: new driver for power/energy/temp meters in IBM System X hardware

This driver reads IBM Active Energy Manager energy/temperature/power
sensors on IBM System X hardware.

[[email protected]: fix printk warnings]
Signed-off-by: Darrick J. Wong <[email protected]>
Cc: "Mark M. Hoffman" <[email protected]>
Cc: Corey Minyard <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Documentation/hwmon/ibmaem

@@ -0,0 +1,37 @@
+Kernel driver ibmaem
+======================
+
+Supported systems:
+  * Any recent IBM System X server with Active Energy Manager support.
+    This includes the x3350, x3550, x3650, x3655, x3755, x3850 M2,
+    x3950 M2, and certain HS2x/LS2x/QS2x blades.  The IPMI host interface
+    driver ("ipmi-si") needs to be loaded for this driver to do anything.
+    Prefix: 'ibmaem'
+    Datasheet: Not available
+
+Author: Darrick J. Wong
+
+Description
+-----------
+
+This driver implements sensor reading support for the energy and power
+meters available on various IBM System X hardware through the BMC.  All
+sensor banks will be exported as platform devices; this driver can talk
+to both v1 and v2 interfaces.  This driver is completely separate from the
+older ibmpex driver.
+
+The v1 AEM interface has a simple set of features to monitor energy use.
+There is a register that displays an estimate of raw energy consumption
+since the last BMC reset, and a power sensor that returns average power
+use over a configurable interval.
+
+The v2 AEM interface is a bit more sophisticated, being able to present
+a wider range of energy and power use registers, the power cap as
+set by the AEM software, and temperature sensors.
+
+Special Features
+----------------
+
+The "power_cap" value displays the current system power cap, as set by
+the Active Energy Manager software.  Setting the power cap from the host
+is not currently supported.

drivers/hwmon/Kconfig

@@ -330,6 +330,20 @@ config SENSORS_CORETEMP
 	  sensor inside your CPU. Supported all are all known variants
 	  of Intel Core family.
 
+config SENSORS_IBMAEM
+	tristate "IBM Active Energy Manager temperature/power sensors and control"
+	select IPMI_SI
+	depends on IPMI_HANDLER
+	help
+	  If you say yes here you get support for the temperature and
+	  power sensors and capping hardware in various IBM System X
+	  servers that support Active Energy Manager.  This includes
+	  the x3350, x3550, x3650, x3655, x3755, x3850 M2, x3950 M2,
+	  and certain HS2x/LS2x/QS2x blades.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called ibmaem.
+
 config SENSORS_IBMPEX
 	tristate "IBM PowerExecutive temperature/power sensors"
 	select IPMI_SI

drivers/hwmon/Makefile

@@ -41,6 +41,7 @@ obj-$(CONFIG_SENSORS_GL518SM)	+= gl518sm.o
 obj-$(CONFIG_SENSORS_GL520SM)	+= gl520sm.o
 obj-$(CONFIG_SENSORS_HDAPS)	+= hdaps.o
 obj-$(CONFIG_SENSORS_I5K_AMB)	+= i5k_amb.o
+obj-$(CONFIG_SENSORS_IBMAEM)	+= ibmaem.o
 obj-$(CONFIG_SENSORS_IBMPEX)	+= ibmpex.o
 obj-$(CONFIG_SENSORS_IT87)	+= it87.o
 obj-$(CONFIG_SENSORS_K8TEMP)	+= k8temp.o