dt-bindings: backlight: Update qcom-spmi-wled DT bindings

Add IIO properties io-channels and io-channel-names, which may
be used for WLED to read QG channels. While at it, remove usage
of PMIC revid.

Change-Id: Ib8503190f0012b85016231d9697c65407ac01a47

bindings/leds/backlight/qcom-spmi-wled.txt

@@ -138,11 +138,6 @@ platforms. The PMIC is connected to the host processor via SPMI bus.
 		    3 - External signal (e.g. LPG) is used for dimming
 		    This property is applicable only to WLED5 peripheral.
 
-- qcom,pmic-revid
-	Usage:      optional
-	Value type: <phandle>
-	Definition: If specified, can be used to get PMIC revision information.
-
 - qcom,leds-per-string
 	Usage:      optional
 	Value type: <u32>
@@ -150,6 +145,18 @@ platforms. The PMIC is connected to the host processor via SPMI bus.
 		    during selfie flash operation. If not specified, available
 		    current calculated is simply the configured threshold.
 
+- io-channels
+	Usage:      optional
+	Value type: <phandle-array>
+	Definition: IIO channel specifiers for each name in io-channel-names.
+
+- io-channel-names
+	Usage:      optional
+	Value type: <string-array>
+	Definition: Names of the IIO channels that are used by WLED.
+		        For details about IIO bindings see:
+			    Documentation/devicetree/bindings/iio/iio-bindings.txt
+
 Following properties are for child subnodes that are needed for WLED preflash
 (or torch), flash and switch. These child subnodes can be specified only for
 PMICs that has WLED5 (e.g. PM8150L).
@@ -271,6 +278,14 @@ qcom-wled@d800 {
 	interrupt-names = "ovp-irq";
 	qcom,string-cfg = <7>;
 
+	io-channels = <&pm7250b_qg PSY_IIO_RESISTANCE>,
+		<&pm7250b_qg PSY_IIO_VOLTAGE_OCV>,
+		<&pm7250b_qg PSY_IIO_CURRENT_NOW>;
+
+	io-channel-names = "rbatt",
+		"voltage_ocv",
+		"current_now";
+
 	wled_torch: qcom,wled-torch {
 		label = "torch";
 		qcom,wled-torch-fsc = <40>;