i2c: jz4780: Add i2c bus controller driver for Ingenic JZ4780

Adds the i2c bus controller driver for the Ingenic JZ4780 SoC.
Signed-off-by: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Documentation/devicetree/bindings/i2c/i2c-jz4780.txt

+* Ingenic JZ4780 I2C Bus controller
+
+Required properties:
+- compatible: should be "ingenic,jz4780-i2c"
+- reg: Should contain the address & size of the I2C controller registers.
+- interrupts: Should specify the interrupt provided by parent.
+- clocks: Should contain a single clock specifier for the JZ4780 I2C clock.
+- clock-frequency: desired I2C bus clock frequency in Hz.
+
+Recommended properties:
+- pinctrl-names: should be "default";
+- pinctrl-0: phandle to pinctrl function
+
+Optional properties:
+- interrupt-parent: Should be the phandle of the interrupt controller that
+  delivers interrupts to the I2C block.
+
+Example
+
+/ {
+	i2c4: i2c4@0x10054000 {
+		compatible = "ingenic,jz4780-i2c";
+		reg = <0x10054000 0x1000>;
+
+		interrupt-parent = <&intc>;
+		interrupts = <56>;
+
+		clocks = <&cgu JZ4780_CLK_SMB4>;
+		clock-frequency = <100000>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&pins_i2c4_data>;
+
+	};
+};
+

drivers/i2c/busses/Kconfig

@@ -583,6 +583,15 @@ config I2C_IOP3XX
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-iop3xx.
 
+config I2C_JZ4780
+	tristate "JZ4780 I2C controller interface support"
+	depends on MACH_JZ4780 || COMPILE_TEST
+	help
+	 If you say yes to this option, support will be included for the
+	 Ingenic JZ4780 I2C controller.
+
+	 If you don't know what to do here, say N.
+
 config I2C_KEMPLD
 	tristate "Kontron COM I2C Controller"
 	depends on MFD_KEMPLD

drivers/i2c/busses/Makefile

@@ -56,6 +56,7 @@ obj-$(CONFIG_I2C_IBM_IIC)	+= i2c-ibm_iic.o
 obj-$(CONFIG_I2C_IMG)		+= i2c-img-scb.o
 obj-$(CONFIG_I2C_IMX)		+= i2c-imx.o
 obj-$(CONFIG_I2C_IOP3XX)	+= i2c-iop3xx.o
+obj-$(CONFIG_I2C_JZ4780)	+= i2c-jz4780.o
 obj-$(CONFIG_I2C_KEMPLD)	+= i2c-kempld.o
 obj-$(CONFIG_I2C_MESON)		+= i2c-meson.o
 obj-$(CONFIG_I2C_MPC)		+= i2c-mpc.o