* RT5508 SPK AMP controller

Required Specific Properties:

- compatible : "richtek,rt5508"

Optional Specific Properties:

- rt,chan_sel : default channel selection.
                0 -> left channel
		1 -> (L+R)/2
		2 -> right channel

- rt,do_enable : data output enable or not.

- rt,tdm_dac_slot : default tdm dac slot chosen.
		    0 -> If channel sel is left, then dac will be chosen to TDM slot 0.
			 otherwise, channel sel is right, dac will be chosen to TDM slot 1.
		    1 -> If channel sel is left, then dac will be chosen to TDM slot 2.
			 otherwise, channel sel is right, dac will be chosen to TDM slot 3.

- rt,tdm_adc_slot : default tdm adc slot chosen.
		    0 -> If channel sel is left, then adc will be chosen to TDM slot 0.
			 otherwise, channel sel is right, adc will be chosen to TDM slot 1.
		    1 -> If channel sel is left, then adc will be chosen to TDM slot 2.
			 otherwise, channel sel is right, adc will be chosen to TDM slot 3.

- rt,tdm_mode : tdm mode enable or not.

- proprietary_param : proprietary param for Richtek RT5508,
		      something liks as the speaker protection/MBDRC/ALC, etc...

Example:

	i2c@12C70000 {
		status = "ok";
		rt5508: rt5508@34 {
			status = "ok";
			compatible = "richtek,rt5508";
			reg = <0x34>;
		};
	};
