i2c: iproc: Add Broadcom iProc I2C Driver

Add initial support to the Broadcom iProc I2C controller found in the
iProc family of SoCs.

The iProc I2C controller has separate internal TX and RX FIFOs, each has
a size of 64 bytes. The iProc I2C controller supports two bus speeds
including standard mode (100kHz) and fast mode (400kHz)
Signed-off-by: Ray Jui <rjui@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
Reviewed-by: Kevin Cernekee <cernekee@chromium.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Documentation/devicetree/bindings/i2c/brcm,iproc-i2c.txt

+Broadcom iProc I2C controller
+
+Required properties:
+
+- compatible:
+    Must be "brcm,iproc-i2c"
+
+- reg:
+    Define the base and range of the I/O address space that contain the iProc
+    I2C controller registers
+
+- interrupts:
+    Should contain the I2C interrupt
+
+- clock-frequency:
+    This is the I2C bus clock. Need to be either 100000 or 400000
+
+- #address-cells:
+    Always 1 (for I2C addresses)
+
+- #size-cells:
+    Always 0
+
+Example:
+	i2c0: i2c@18008000 {
+		compatible = "brcm,iproc-i2c";
+		reg = <0x18008000 0x100>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+		interrupts = <GIC_SPI 85 IRQ_TYPE_NONE>;
+		clock-frequency = <100000>;
+
+		codec: wm8750@1a {
+			compatible = "wlf,wm8750";
+			reg = <0x1a>;
+		};
+	};

drivers/i2c/busses/Kconfig

@@ -372,6 +372,16 @@ config I2C_BCM2835
 	  This support is also available as a module.  If so, the module
 	  will be called i2c-bcm2835.
 
+config I2C_BCM_IPROC
+	tristate "Broadcom iProc I2C controller"
+	depends on ARCH_BCM_IPROC || COMPILE_TEST
+	default ARCH_BCM_IPROC
+	help
+	  If you say yes to this option, support will be included for the
+	  Broadcom iProc I2C controller.
+
+	  If you don't know what to do here, say N.
+
 config I2C_BCM_KONA
 	tristate "BCM Kona I2C adapter"
 	depends on ARCH_BCM_MOBILE

drivers/i2c/busses/Makefile

@@ -33,6 +33,7 @@ obj-$(CONFIG_I2C_AT91)		+= i2c-at91.o
 obj-$(CONFIG_I2C_AU1550)	+= i2c-au1550.o
 obj-$(CONFIG_I2C_AXXIA)		+= i2c-axxia.o
 obj-$(CONFIG_I2C_BCM2835)	+= i2c-bcm2835.o
+obj-$(CONFIG_I2C_BCM_IPROC)	+= i2c-bcm-iproc.o
 obj-$(CONFIG_I2C_BLACKFIN_TWI)	+= i2c-bfin-twi.o
 obj-$(CONFIG_I2C_CADENCE)	+= i2c-cadence.o
 obj-$(CONFIG_I2C_CBUS_GPIO)	+= i2c-cbus-gpio.o