i2c: riic: add driver

Tested with a r7s72100 genmai board acessing an eeprom.
Signed-off-by: Wolfram Sang <wsa@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

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

+Device tree configuration for Renesas RIIC driver
+
+Required properties:
+- compatible      : "renesas,riic-<soctype>". "renesas,riic-rz" as fallback
+- reg             : address start and address range size of device
+- interrupts      : 8 interrupts (TEI, RI, TI, SPI, STI, NAKI, ALI, TMOI)
+- clock-frequency : frequency of bus clock in Hz
+- #address-cells  : should be <1>
+- #size-cells     : should be <0>
+
+Pinctrl properties might be needed, too. See there.
+
+Example:
+
+	i2c0: i2c@fcfee000 {
+		compatible = "renesas,riic-r7s72100", "renesas,riic-rz";
+		reg = <0xfcfee000 0x44>;
+		interrupts = <0 157 IRQ_TYPE_LEVEL_HIGH>,
+			     <0 158 IRQ_TYPE_EDGE_RISING>,
+			     <0 159 IRQ_TYPE_EDGE_RISING>,
+			     <0 160 IRQ_TYPE_LEVEL_HIGH>,
+			     <0 161 IRQ_TYPE_LEVEL_HIGH>,
+			     <0 162 IRQ_TYPE_LEVEL_HIGH>,
+			     <0 163 IRQ_TYPE_LEVEL_HIGH>,
+			     <0 164 IRQ_TYPE_LEVEL_HIGH>;
+		clock-frequency = <100000>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+	};

drivers/i2c/busses/Kconfig

@@ -648,6 +648,16 @@ config I2C_PXA_SLAVE
 	  is necessary for systems where the PXA may be a target on the
 	  I2C bus.
 
+config I2C_RIIC
+	tristate "Renesas RIIC adapter"
+	depends on ARCH_SHMOBILE || COMPILE_TEST
+	help
+	  If you say yes to this option, support will be included for the
+	  Renesas RIIC I2C interface.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-riic.
+
 config HAVE_S3C2410_I2C
 	bool
 	help

drivers/i2c/busses/Makefile

@@ -63,6 +63,7 @@ obj-$(CONFIG_I2C_PNX)		+= i2c-pnx.o
 obj-$(CONFIG_I2C_PUV3)		+= i2c-puv3.o
 obj-$(CONFIG_I2C_PXA)		+= i2c-pxa.o
 obj-$(CONFIG_I2C_PXA_PCI)	+= i2c-pxa-pci.o
+obj-$(CONFIG_I2C_RIIC)		+= i2c-riic.o
 obj-$(CONFIG_I2C_S3C2410)	+= i2c-s3c2410.o
 obj-$(CONFIG_I2C_S6000)		+= i2c-s6000.o
 obj-$(CONFIG_I2C_SH7760)	+= i2c-sh7760.o