i2c: Add support for Renesas rcar

This supports i2c controller for Renesas rcar.

Signed-off-by: Hisashi Nakamura <hisashi.nakamura.ak@renesas.com>
Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
diff --git a/README b/README
index 7dc4f23..e209c89 100644
--- a/README
+++ b/README
@@ -2014,6 +2014,20 @@
 		If thoses defines are not set, default value is 100000
 		for speed, and 0 for slave.
 
+		- drivers/i2c/rcar_i2c.c:
+		  - activate this driver with CONFIG_SYS_I2C_RCAR
+		  - This driver adds 4 i2c buses
+
+		  - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
+		  - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
+		  - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
+		  - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
+		  - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
+		  - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
+		  - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
+		  - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
+		  - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
+
 		additional defines:
 
 		CONFIG_SYS_NUM_I2C_BUSES