i2c: vt8500: Add support for I2C bus on Wondermedia SoCs

This patch adds support for the I2C bus controllers found on Wondermedia
8xxx-series SoCs. Only master-mode is supported.

Signed-off-by: Tony Prisk <linux@prisktech.co.nz>
[wsa: fixed one macro to shift 8 instead of 16]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Documentation/devicetree/bindings/i2c/i2c-vt8500.txt

@@ -0,0 +1,24 @@
+* Wondermedia I2C Controller
+
+Required properties :
+
+ - compatible : should be "wm,wm8505-i2c"
+ - reg : Offset and length of the register set for the device
+ - interrupts : <IRQ> where IRQ is the interrupt number
+ - clocks : phandle to the I2C clock source
+
+Optional properties :
+
+ - clock-frequency : desired I2C bus clock frequency in Hz.
+ Valid values are 100000 and 400000.
+ Default to 100000 if not specified, or invalid value.
+
+Example :
+
+ i2c_0: i2c@d8280000 {
+ compatible = "wm,wm8505-i2c";
+ reg = <0xd8280000 0x1000>;
+ interrupts = <19>;
+ clocks = <&clki2c0>;
+ clock-frequency = <400000>;
+ };

MAINTAINERS

@@ -1285,6 +1285,7 @@ S: Maintained
 F: arch/arm/mach-vt8500/
 F: drivers/clocksource/vt8500_timer.c
 F: drivers/gpio/gpio-vt8500.c
+F: drivers/i2c/busses/i2c-wmt.c
 F: drivers/mmc/host/wmt-sdmmc.c
 F: drivers/pwm/pwm-vt8500.c
 F: drivers/rtc/rtc-vt8500.c

drivers/i2c/busses/Kconfig

@@ -714,6 +714,16 @@ config I2C_VERSATILE
  This driver can also be built as a module. If so, the module
  will be called i2c-versatile.
 
+config I2C_WMT
+ tristate "Wondermedia WM8xxx SoC I2C bus support"
+ depends on ARCH_VT8500
+ help
+ Say yes if you want to support the I2C bus on Wondermedia 8xxx-series
+ SoCs.
+
+ This driver can also be built as a module. If so, the module will be
+ called i2c-wmt.
+
 config I2C_OCTEON
  tristate "Cavium OCTEON I2C bus support"
  depends on CPU_CAVIUM_OCTEON

drivers/i2c/busses/Makefile

@@ -70,6 +70,7 @@ obj-$(CONFIG_I2C_SIRF) += i2c-sirf.o
 obj-$(CONFIG_I2C_STU300) += i2c-stu300.o
 obj-$(CONFIG_I2C_TEGRA) += i2c-tegra.o
 obj-$(CONFIG_I2C_VERSATILE) += i2c-versatile.o
+obj-$(CONFIG_I2C_WMT) += i2c-wmt.o
 obj-$(CONFIG_I2C_OCTEON) += i2c-octeon.o
 obj-$(CONFIG_I2C_XILINX) += i2c-xiic.o
 obj-$(CONFIG_I2C_XLR) += i2c-xlr.o