wm8978_overlay.dts

/*
 * Copyright 2017 NextThing Co
 * Peter Nyboer <peter@nextthing.co>
 *     This file is free software; you can redistribute it and/or
 *     modify it under the terms of the GNU General Public License as
 *     published by the Free Software Foundation; either version 2 of the
 *     License, or (at your option) any later version.
 *
 *     This file is distributed in the hope that it will be useful,
 *     but WITHOUT ANY WARRANTY; without even the implied warranty of
 *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *     GNU General Public License for more details.
 */
/dts-v1/;
/plugin/;

/ {
    compatible = "nextthing,chip", "allwinner,sun5i-r8",  "nextthing,gr8-evb", "nextthing,gr8";

    /*
     * enable i2s0 bus.
     */
    fragment@0 {
        target = <&i2s0>;
        __overlay__ {
          pinctrl-names = "default";
          pinctrl-0 = <&i2s0_mclk_pins_a>, <&i2s0_data_pins_a>;
          status = "okay";
        };
    };

    /*
     * enable the wm8978 codec over I2S for CHIP Pro
     */
    fragment@1 {
        target-path = "/i2s";

        __overlay__ {
            compatible = "simple-audio-card";
            simple-audio-card,name = "NTC-GR8-wm8978";
            simple-audio-card,format = "i2s";
            simple-audio-card,mclk-fs = <512>;

            simple-audio-card,cpu {
              sound-dai = <&i2s0>;
            };

            simple-audio-card,codec {
              sound-dai = <&wm8978>;
            };
        };
    };

		/*
		* enable i2c bus 1 for wm8978 comm
		*/
    fragment@2 {
      target = "<&i2c1>";

      __overlay__ {
        pinctrl-names = "default";
        pinctrl-0 = <&i2c1_pins_a>;
        status = "okay";

        wm8978: codec@1a {
          #sound-dai-cells = <0>;
          compatible = "wlf,wm8978";
          reg = <0x1a>;
        };
      };
    };

		/*
		* describe codec for DAC
		*/
    fragment@3 {
    	target-path = "/codec";

			__overlay__ {
				compatible = "nextthing,gr8-audio";
				allwinner,i2s-controller = <&i2s0>;
				allwinner,audio-codec = <&wm8978>;
			};
		};
};