i2c: xlp9xx: Driver for Netlogic XLP9XX/5XX I2C controller

Add an I2C bus driver i2c-xlp9xx.c to support the I2C block in the
XLP9xx/XLP5xx MIPS SoC. Update Kconfig and Makefile to add the
CONFIG_I2C_XLP9XX option.
Signed-off-by: Subhendu Sekhar Behera <sbehera@broadcom.com>
Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Reviewed-by: Ray Jui <rjui@broadcom.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Documentation/devicetree/bindings/i2c/i2c-xlp9xx.txt

+Device tree configuration for the I2C controller on the XLP9xx/5xx SoC
+
+Required properties:
+- compatible      : should be "netlogic,xlp980-i2c"
+- reg             : bus address start and address range size of device
+- interrupts      : interrupt number
+
+Optional properties:
+- clock-frequency : frequency of bus clock in Hz
+                    Defaults to 100 KHz when the property is not specified
+
+Example:
+
+i2c0: i2c@113100 {
+	compatible = "netlogic,xlp980-i2c";
+	#address-cells = <1>;
+	#size-cells = <0>;
+	reg = <0 0x113100 0x100>;
+	clock-frequency = <400000>;
+	interrupts = <30>;
+	interrupt-parent = <&pic>;
+};

drivers/i2c/busses/Kconfig

@@ -916,6 +916,16 @@ config I2C_XLR
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-xlr.
 
+config I2C_XLP9XX
+	tristate "XLP9XX I2C support"
+	depends on CPU_XLP || COMPILE_TEST
+	help
+	  This driver enables support for the on-chip I2C interface of
+	  the Broadcom XLP9xx/XLP5xx MIPS processors.
+
+	  This driver can also be built as a module.  If so, the module will
+	  be called i2c-xlp9xx.
+
 config I2C_RCAR
 	tristate "Renesas R-Car I2C Controller"
 	depends on ARCH_SHMOBILE || COMPILE_TEST

drivers/i2c/busses/Makefile

@@ -89,6 +89,7 @@ obj-$(CONFIG_I2C_WMT)		+= i2c-wmt.o
 obj-$(CONFIG_I2C_OCTEON)	+= i2c-octeon.o
 obj-$(CONFIG_I2C_XILINX)	+= i2c-xiic.o
 obj-$(CONFIG_I2C_XLR)		+= i2c-xlr.o
+obj-$(CONFIG_I2C_XLP9XX)	+= i2c-xlp9xx.o
 obj-$(CONFIG_I2C_RCAR)		+= i2c-rcar.o
 
 # External I2C/SMBus adapter drivers