drivers: hwmon: Add On-Chip Controller driver

new file mode 100644
index 0000000..79d1642
@@ -0,0 +1,40 @@
+Kernel driver occ
+=================
+
+Supported chips:
+ * ASPEED AST2400
+ * ASPEED AST2500
+
+Please note that the chip must be connected to a POWER8 or POWER9 processor
+(see the BMC - Host Communications section).
+
+Author: Eddie James <[email protected]>
+
+Description
+-----------
+
+This driver implements support for the OCC (On-Chip Controller) on the IBM
+POWER8 and POWER9 processors, from a BMC (Baseboard Management Controller). The
+OCC is an embedded processor that provides real time power and thermal
+monitoring.
+
+This driver provides an interface on a BMC to poll OCC sensor data, set user
+power caps, and perform some basic OCC error handling.
+
+Currently, all versions of the OCC support four types of sensor data: power,
+temperature, frequency, and "caps," which indicate limits and thresholds used
+internally on the OCC.
+
+BMC - Host Communications
+-------------------------
+
+For the POWER8 application, the BMC can communicate with the P8 over I2C bus.
+However, to access the OCC register space, any data transfer must use a SCOM
+operation. SCOM is a procedure to initiate a data transfer, typically of 8
+bytes. SCOMs consist of writing a 32-bit command register and then
+reading/writing two 32-bit data registers. This driver implements these
+SCOM operations over I2C bus in order to communicate with the OCC.
+
+For the POWER9 application, the BMC can communicate with the P9 over FSI bus
+and SBE engine. Once again, SCOM operations are required. This driver will
+implement SCOM ops over FSI/SBE. This will require the FSI driver.

index 5f10c28..193a13b 100644
@@ -9128,6 +9128,13 @@ T:	git git://linuxtv.org/media_tree.git
 S:	Maintained
 F:	drivers/media/i2c/ov7670.c
 
+ON-CHIP CONTROLLER HWMON DRIVER
+M:	Eddie James <[email protected]>
+L:	[email protected]
+S:	Maintained
+F:	Documentation/hwmon/occ
+F:	drivers/hwmon/occ/
+
 ONENAND FLASH DRIVER
 M:	Kyungmin Park <[email protected]>
 L:	[email protected]

index 190d270..e80ca81 100644
@@ -1240,6 +1240,8 @@ config SENSORS_NSA320
 	  This driver can also be built as a module. If so, the module
 	  will be called nsa320-hwmon.
 
+source drivers/hwmon/occ/Kconfig
+
 config SENSORS_PCF8591
 	tristate "Philips PCF8591 ADC/DAC"
 	depends on I2C

index d2cb7e8..c7ec5d4 100644
@@ -169,6 +169,7 @@ obj-$(CONFIG_SENSORS_WM831X)	+= wm831x-hwmon.o
 obj-$(CONFIG_SENSORS_WM8350)	+= wm8350-hwmon.o
 obj-$(CONFIG_SENSORS_XGENE)	+= xgene-hwmon.o
 
+obj-$(CONFIG_SENSORS_PPC_OCC)	+= occ/
 obj-$(CONFIG_PMBUS)		+= pmbus/
 
 ccflags-$(CONFIG_HWMON_DEBUG_CHIP) := -DDEBUG

new file mode 100644
index 0000000..cdb64a7
@@ -0,0 +1,15 @@
+#
+# On Chip Controller configuration
+#
+
+menuconfig SENSORS_PPC_OCC
+	bool "PPC On-Chip Controller"
+	help
+	  If you say yes here you get support to monitor Power CPU
+	  sensors via the On-Chip Controller (OCC).
+
+	  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 occ.

new file mode 100644
index 0000000..93cb52f
@@ -0,0 +1 @@
+obj-$(CONFIG_SENSORS_PPC_OCC) += occ.o

index 79d1642..d0bdf06 100644
@@ -25,6 +25,68 @@ Currently, all versions of the OCC support four types of sensor data: power,
 temperature, frequency, and "caps," which indicate limits and thresholds used
 internally on the OCC.
 
+sysfs Entries
+-------------
+
+The OCC driver uses the hwmon sysfs framework to provide data to userspace.
+
+The driver exports a number of sysfs files for each type of sensor. The
+sensor-specific files vary depending on the processor type, though many of the
+attributes are common for both the POWER8 and POWER9.
+
+The hwmon interface cannot define every type of sensor that may be used.
+Therefore, the frequency sensor on the OCC uses the "input" type sensor defined
+by the hwmon interface, rather than defining a new type of custom sensor.
+
+Below are detailed the names and meaning of each sensor file for both types of
+processors. All sensors are read-only unless otherwise specified. <x> indicates
+the hwmon index. sensor id indicates the unique internal OCC identifer. Please
+see the POWER OCC specification for details on all these sensor values.
+
+frequency:
+	all processors:
+		in<x>_input - frequency value
+		in<x>_label - sensor id
+temperature:
+	POWER8:
+		temp<x>_input - temperature value
+		temp<x>_label - sensor id
+	POWER9 (in addition to above):
+		temp<x>_type - FRU type
+
+power:
+	POWER8:
+		power<x>_input - power value
+		power<x>_label - sensor id
+		power<x>_average - accumulator
+		power<x>_average_interval - update tag (number of samples in
+			accumulator)
+	POWER9:
+		power<x>_input - power value
+		power<x>_label - sensor id
+		power<x>_average_min - accumulator[0]
+		power<x>_average_max - accumulator[1] (64 bits total)
+		power<x>_average_interval - update tag
+		power<x>_reset_history - (function_id | (apss_channel << 8)
+
+caps:
+	POWER8:
+		power<x>_cap - current powercap
+		power<x>_cap_max - max powercap
+		power<x>_cap_min - min powercap
+		power<x>_max - normal powercap
+		power<x>_alarm - user powercap, r/w
+	POWER9:
+		power<x>_cap_alarm - user powercap source
+
+The driver also provides two sysfs entries through hwmon to better
+control the driver and monitor the master OCC. Though there may be multiple
+OCCs present on the system, these two files are only present for the "master"
+OCC.
+	name - read the name of the driver
+	update_interval - read or write the minimum interval for polling the
+		OCC.
+
 BMC - Host Communications
 -------------------------
 

index 93cb52f..a6881f9 100644
@@ -1 +1 @@
-obj-$(CONFIG_SENSORS_PPC_OCC) += occ.o
+obj-$(CONFIG_SENSORS_PPC_OCC) += occ.o occ_sysfs.o

index d0bdf06..143951e 100644
@@ -25,6 +25,15 @@ Currently, all versions of the OCC support four types of sensor data: power,
 temperature, frequency, and "caps," which indicate limits and thresholds used
 internally on the OCC.
 
+The format for the POWER8 OCC sensor data can be found in the P8 OCC
+specification:
+github.com/open-power/docs/blob/master/occ/OCC_OpenPwr_FW_Interfaces.pdf
+This document provides the details of the OCC sensors: power, frequency,
+temperature, and caps. These sensor formats are specific to the POWER8 OCC. A
+number of data structures, such as command format, response headers, and the
+like, are also defined in this specification, and are common to both POWER8 and
+POWER9 OCCs.
+
 sysfs Entries
 -------------
 

new file mode 100644
index 0000000..b0d2b36
@@ -0,0 +1,13 @@
+HWMON I2C driver for IBM POWER CPU OCC (On Chip Controller)
+
+Required properties:
+ - compatible: must be "ibm,p8-occ-i2c"
+ - reg: physical address
+
+Example:
+i2c3: i2c-bus@100 {
+	occ@50 {
+		compatible = "ibm,p8-occ-i2c";
+		reg = <0x50>;
+	};
+};

index cdb64a7..3a5188f 100644
@@ -13,3 +13,17 @@ menuconfig SENSORS_PPC_OCC
 
 	  This driver can also be built as a module. If so, the module
 	  will be called occ.
+
+if SENSORS_PPC_OCC
+
+config SENSORS_PPC_OCC_P8_I2C
+	tristate "POWER8 OCC hwmon support"
+	depends on I2C
+	help
+	 Provide a hwmon sysfs interface for the POWER8 On-Chip Controller,
+	 exposing temperature, frequency and power measurements.
+
+	 This driver can also be built as a module. If so, the module will be
+	 called p8-occ-i2c.
+
+endif

index a6881f9..9294b58 100644
@@ -1 +1,2 @@
 obj-$(CONFIG_SENSORS_PPC_OCC) += occ.o occ_sysfs.o
+obj-$(CONFIG_SENSORS_PPC_OCC_P8_I2C) += occ_scom_i2c.o occ_p8.o p8_occ_i2c.o

index 143951e..6cea853 100644
@@ -34,6 +34,9 @@ number of data structures, such as command format, response headers, and the
 like, are also defined in this specification, and are common to both POWER8 and
 POWER9 OCCs.
 
+There is currently no public P9 OCC specification, and the data structures
+defined in the POWER9 OCC driver are subject to change.
+
 sysfs Entries
 -------------