i2c: uniphier_f: add UniPhier FIFO-builtin I2C driver

Add support for on-chip I2C controller used on newer UniPhier SoCs
such as PH1-Pro4, PH1-Pro5, etc.  This adapter is equipped with
8-depth TX/RX FIFOs.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Documentation/devicetree/bindings/i2c/i2c-uniphier-f.txt

+UniPhier I2C controller (FIFO-builtin)
+
+Required properties:
+- compatible: should be "socionext,uniphier-fi2c".
+- #address-cells: should be 1.
+- #size-cells: should be 0.
+- reg: offset and length of the register set for the device.
+- interrupts: a single interrupt specifier.
+- clocks: phandle to the input clock.
+
+Optional properties:
+- clock-frequency: desired I2C bus frequency in Hz.  The maximum supported
+  value is 400000.  Defaults to 100000 if not specified.
+
+Examples:
+
+	i2c0: i2c@58780000 {
+		compatible = "socionext,uniphier-fi2c";
+		reg = <0x58780000 0x80>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+		interrupts = <0 41 4>;
+		clocks = <&i2c_clk>;
+		clock-frequency = <100000>;
+	};

drivers/i2c/busses/Kconfig

@@ -910,6 +910,14 @@ config I2C_UNIPHIER
 	  the UniPhier FIFO-less I2C interface embedded in PH1-LD4, PH1-sLD8,
 	  or older UniPhier SoCs.
 
+config I2C_UNIPHIER_F
+	tristate "UniPhier FIFO-builtin I2C controller"
+	depends on ARCH_UNIPHIER
+	help
+	  If you say yes to this option, support will be included for
+	  the UniPhier FIFO-builtin I2C interface embedded in PH1-Pro4,
+	  PH1-Pro5, or newer UniPhier SoCs.
+
 config I2C_VERSATILE
 	tristate "ARM Versatile/Realview I2C bus support"
 	depends on ARCH_VERSATILE || ARCH_REALVIEW || ARCH_VEXPRESS

drivers/i2c/busses/Makefile

@@ -88,6 +88,7 @@ obj-$(CONFIG_I2C_STU300)	+= i2c-stu300.o
 obj-$(CONFIG_I2C_SUN6I_P2WI)	+= i2c-sun6i-p2wi.o
 obj-$(CONFIG_I2C_TEGRA)		+= i2c-tegra.o
 obj-$(CONFIG_I2C_UNIPHIER)	+= i2c-uniphier.o
+obj-$(CONFIG_I2C_UNIPHIER_F)	+= i2c-uniphier-f.o
 obj-$(CONFIG_I2C_VERSATILE)	+= i2c-versatile.o
 obj-$(CONFIG_I2C_WMT)		+= i2c-wmt.o
 obj-$(CONFIG_I2C_OCTEON)	+= i2c-octeon.o