ASoC: sgtl500: Document the required supplies

sgtl5000 has two required supplies: VDDA and VDDIO and one optional supply:
VDDD, so document this properly.

Not passing VDDA and VDDIO prevents the driver to probe successfully.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/sound/sgtl5000.txt b/Documentation/devicetree/bindings/sound/sgtl5000.txt
index 955df60a118c..d556dcb8816b 100644
--- a/Documentation/devicetree/bindings/sound/sgtl5000.txt
+++ b/Documentation/devicetree/bindings/sound/sgtl5000.txt
@@ -7,10 +7,20 @@ Required properties:
 
 - clocks : the clock provider of SYS_MCLK
 
+- VDDA-supply : the regulator provider of VDDA
+
+- VDDIO-supply: the regulator provider of VDDIO
+
+Optional properties:
+
+- VDDD-supply : the regulator provider of VDDD
+
 Example:
 
 codec: sgtl5000@0a {
         compatible = "fsl,sgtl5000";
         reg = <0x0a>;
         clocks = <&clks 150>;
+        VDDA-supply = <&reg_3p3v>;
+        VDDIO-supply = <&reg_3p3v>;
 };