i2c: uniphier: add UniPhier FIFO-less I2C driver

Add support for on-chip I2C controller used on old UniPhier SoCs
such as PH1-LD4, PH1-sLD8, etc.  This adapter is so simple that
it has no FIFO in it.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 14147ec..6a40e16 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -902,6 +902,14 @@
 	  If you say yes to this option, support will be included for the
 	  I2C controller embedded in NVIDIA Tegra SOCs
 
+config I2C_UNIPHIER
+	tristate "UniPhier FIFO-less I2C controller"
+	depends on ARCH_UNIPHIER
+	help
+	  If you say yes to this option, support will be included for
+	  the UniPhier FIFO-less I2C interface embedded in PH1-LD4, PH1-sLD8,
+	  or older UniPhier SoCs.
+
 config I2C_VERSATILE
 	tristate "ARM Versatile/Realview I2C bus support"
 	depends on ARCH_VERSATILE || ARCH_REALVIEW || ARCH_VEXPRESS