* MediaTek MT5870 I2C master controller

The MediaTek MT5870 I2C controller is used to interface with I2C devices.

Required properties:

  - compatible: must be "mediatek,mt5870-i2c"
  - reg: physical base address and length of the control registers.
  - interrupts: interrupt number to the cpu.
  #- TODO: add clocks after clock framework ready
  - #address-cells: should be <1>
  - #size-cells: should be <0>
  #- TODO: remove pad-mode after pinctrl ready
  - pad-mode: pad mux setting for SDA, SCL
  #- TODO: add pinctrl-names and pinctrl-0 after pinctrl ready

Optional properties:

  - clock-frequency: Frequency in Hz of the bus when transfer, the default value
    is 100000.
  - start-count: Start condition count, ie. clock(s) between SDA falling and SCL
    falling. The default value is 73.
  - stop-count: Stop condition count, ie. clock(s) between SCL rising and SDA
    rising. The default value is 73.
  - sda-count: SDA hold time, ie. clock(s) between falling edge SCL and SDA
    output. The default value is 5.
  - latch-count: Data latch timing. The default value is 5.
  - scl-stretch: Enable/disable i2c clock stretch

  May specify i2c bus number by adding aliases.

Example:

	aliases {
		/* let i2c sub system set i2c bus index by aliases */
		/* bus index = &bus module */
		i2c0 = &i2c_3;
	};

	i2c_3: i2c@1F223400 {
		compatible = "mediatek,mt5870-i2c";
		reg = <0 0x1F223400 0 0x200>;
		#address-cells = <1>;
		#size-cells = <0>;
		/* TODO: set clock after clock driver ready */
		/* clocks = <&CLK_miic3>; */
		interrupts=<0x0 0x3f 0x4>;
		clock-frequency = <100000>; /* bus speed 100 KHz */
		/* pad mux setting for SDA, SCL */
		/* TODO: modify after pinctrl finish */
		pad-mode = <2>;
		/* proprietary i2c parameter */
		start-count = <73>;
		stop-count = <73>;
		sda-count = <5>;
		latch-count = <5>;
		scl-stretch;
		status = "okay";
	};
