hwmon: Add Power8 OCC hwmon driver

Adds a hwmon driver for BMC to monitor Power8 CPU sensors via On Chip
Controller.

Signed-off-by: Yi Li <adamliyi@msn.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>

Author: adamliyi

Documentation/devicetree/bindings/i2c/i2c-ibm-occ.txt

@@ -0,0 +1,13 @@
+HWMON i2c driver for IBM POWER CPU OCC (On Chip Controller)
+
+Required properties:
+ - compatible: must be "ibm,power8-occ-i2c"
+ - reg: physical address
+
+Example:
+i2c3: i2c-bus@100 {
+	occ@50 {
+		compatible = "ibm,occ-i2c";
+		reg = <0x50>;
+	};
+};

arch/arm/boot/dts/aspeed-bmc-opp-barreleye.dts

@@ -60,6 +60,16 @@
 						reg = <0x4a>;
 					};
 				};
+				i2c3: i2c-bus@100 {
+					occ@50 {
+						compatible = "ibm,occ-i2c";
+						reg = <0x50>;
+					};
+					occ@51 {
+						compatible = "ibm,occ-i2c";
+						reg = <0x51>;
+					};
+				};
 
 				i2c6: i2c-bus@1c0 {
 					nct7904@2d {

arch/arm/boot/dts/aspeed-bmc-opp-palmetto.dts

@@ -64,6 +64,13 @@
 						reg = <0x4c>;
 					};
 				};
+
+				i2c3: i2c-bus@100 {
+					occ@50 {
+						compatible = "ibm,occ-i2c";
+						reg = <0x50>;
+					};
+				};
 			};
 		};
 	};

drivers/hwmon/Kconfig

@@ -1167,6 +1167,19 @@ config SENSORS_NCT7904
 	  This driver can also be built as a module.  If so, the module
 	  will be called nct7904.
 
+config SENSORS_POWER8_OCC_I2C
+	tristate "Power8 On Chip Controller i2c driver"
+	depends on I2C
+	help
+	  If you say yes here you get support to monitor Power8 CPU
+	  sensors via the On Chip Controller (OCC) over the i2c bus.
+
+	  Generally this is used by management controllers such as a BMC
+	  on an OpenPower system.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called power8_occ_i2c.
+
 config SENSORS_PCF8591
 	tristate "Philips PCF8591 ADC/DAC"
 	depends on I2C

drivers/hwmon/Makefile

@@ -123,6 +123,7 @@ obj-$(CONFIG_SENSORS_NCT6775)	+= nct6775.o
 obj-$(CONFIG_SENSORS_NCT7802)	+= nct7802.o
 obj-$(CONFIG_SENSORS_NCT7904)	+= nct7904.o
 obj-$(CONFIG_SENSORS_NTC_THERMISTOR)	+= ntc_thermistor.o
+obj-$(CONFIG_SENSORS_POWER8_OCC_I2C)	+= power8_occ_i2c.o
 obj-$(CONFIG_SENSORS_PC87360)	+= pc87360.o
 obj-$(CONFIG_SENSORS_PC87427)	+= pc87427.o
 obj-$(CONFIG_SENSORS_PCF8591)	+= pcf8591.o