rockchip: Add I2C driver

Add an I2C driver for the Rockchip RK3288, using driver model. It should work
for other Rockchip SoCs also.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
index c40bd5c..14adda2 100644
--- a/drivers/i2c/Kconfig
+++ b/drivers/i2c/Kconfig
@@ -58,6 +58,15 @@
 	  bindings are supported.
 	  Binding info: doc/device-tree-bindings/i2c/i2c-gpio.txt
 
+config SYS_I2C_ROCKCHIP
+	bool "Rockchip I2C driver"
+	depends on DM_I2C
+	help
+	  Add support for the Rockchip I2C driver. This is used with various
+	  Rockchip parts such as RK3126, RK3128, RK3036 and RK3288. All chips
+	  have several I2C ports and all are provided, controled by the
+	  device tree.
+
 config SYS_I2C_SANDBOX
 	bool "Sandbox I2C driver"
 	depends on SANDBOX && DM_I2C