ARM: dts: am437x-sk-evm: Add sleep pin settings for mcasp1

When McASP is not in use the pins can be put to sleep mode to conserve
power.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Tested-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/am437x-sk-evm.dts

@@ -364,6 +364,15 @@ mcasp1_pins: mcasp1_pins {
 		>;
 	};
 
+	mcasp1_pins_sleep: mcasp1_pins_sleep {
+		pinctrl-single,pins = <
+			0x10c (PIN_INPUT_PULLDOWN | MUX_MODE7)
+			0x110 (PIN_INPUT_PULLDOWN | MUX_MODE7)
+			0x108 (PIN_INPUT_PULLDOWN | MUX_MODE7)
+			0x144 (PIN_INPUT_PULLDOWN | MUX_MODE7)
+		>;
+	};
+
 	lcd_pins: lcd_pins {
 		pinctrl-single,pins = <
 			0x1c (PIN_OUTPUT_PULLDOWN | MUX_MODE7) /* gpcm_ad7.gpio1_7 */
@@ -640,8 +649,9 @@ &elm {
 };
 
 &mcasp1 {
-	pinctrl-names = "default";
+	pinctrl-names = "default", "sleep";
 	pinctrl-0 = <&mcasp1_pins>;
+	pinctrl-1 = <&mcasp1_pins_sleep>;
 
 	status = "okay";