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+Qualcomm's PM8xxx voltage XOADC
+
+The Qualcomm PM8xxx PMICs contain a HK/XO ADC (Housekeeping/Crystal
+oscillator ADC) encompassing PM8018, PM8038, PM8058 and PM8921.
+
+Required properties:
+
+- compatible: should be one of:
+ "qcom,pm8018-adc"
+ "qcom,pm8038-adc"
+ "qcom,pm8058-adc"
+ "qcom,pm8921-adc"
+
+- reg: should contain the ADC base address in the PMIC, typically
+ 0x197.
+
+- xoadc-ref-supply: should reference a regulator that can supply
+ a reference voltage on demand. The reference voltage may vary
+ with PMIC variant but is typically something like 2.2 or 1.8V.
+
+The following required properties are standard for IO channels, see
+iio-bindings.txt for more details, but notice that this particular
+ADC has a special addressing scheme that require two cells for
+identifying each ADC channel:
+
+- #address-cells: should be set to <2>, the first cell is the
+ prescaler (on PM8058) or premux (on PM8921) with two valid bits
+ so legal values are 0x00, 0x01 or 0x02. The second cell
+ is the main analog mux setting (0x00..0x0f). The combination
+ of prescaler/premux and analog mux uniquely addresses a hardware
+ channel on all systems.
+
+- #size-cells: should be set to <0>
+
+- #io-channel-cells: should be set to <2>, again the cells are
+ precaler or premux followed by the analog muxing line.
+
+- interrupts: should refer to the parent PMIC interrupt controller
+ and reference the proper ADC interrupt.
+
+Required subnodes:
+
+The ADC channels are configured as subnodes of the ADC.
+
+Since some of them are used for calibrating the ADC, these nodes are
+compulsory:
+
+adc-channel@c {
+ reg = <0x00 0x0c>;
+};
+
+adc-channel@d {
+ reg = <0x00 0x0d>;
+};
+
+adc-channel@f {
+ reg = <0x00 0x0f>;
+};
+
+These three nodes are used for absolute and ratiometric calibration
+and only need to have these reg values: they are by hardware definition
+1:1 ratio converters that sample 625, 1250 and 0 milliV and create
+an interpolation calibration for all other ADCs.
+
+Optional subnodes: any channels other than channels [0x00 0x0c],
+[0x00 0x0d] and [0x00 0x0f] are optional.
+
+Required channel node properties:
+
+- reg: should contain the hardware channel number in the range
+ 0 .. 0xff (8 bits).
+
+Optional channel node properties:
+
+- qcom,decimation:
+ Value type: <u32>
+ Definition: This parameter is used to decrease the ADC sampling rate.
+ Quicker measurements can be made by reducing the decimation ratio.
+ Valid values are 512, 1024, 2048, 4096.
+ If the property is not found, a default value of 512 will be used.
+
+- qcom,ratiometric:
+ Value type: <u32>
+ Definition: Channel calibration type. If this property is specified
+ VADC will use a special voltage references for channel
+ calibration. The available references are specified in the
+ as a u32 value setting (see below) and it is compulsory
+ to also specify this reference if ratiometric calibration
+ is selected.
+
+ If the property is not found, the channel will be
+ calibrated with the 0.625V and 1.25V reference channels, also
+ known as an absolute calibration.
+ The reference voltage pairs when using ratiometric calibration:
+ 0 = XO_IN/XOADC_GND
+ 1 = PMIC_IN/XOADC_GND
+ 2 = PMIC_IN/BMS_CSP
+ 3 (invalid)
+ 4 = XOADC_GND/XOADC_GND
+ 5 = XOADC_VREF/XOADC_GND
+
+Example:
+
+xoadc: xoadc@197 {
+ compatible = "qcom,pm8058-adc";
+ reg = <0x197>;
+ interrupts-extended = <&pm8058 76 IRQ_TYPE_EDGE_RISING>;
+ #address-cells = <2>;
+ #size-cells = <0>;
+ #io-channel-cells = <2>;
+
+ vcoin: adc-channel@0 {
+ reg = <0x00 0x00>;
+ };
+ vbat: adc-channel@1 {
+ reg = <0x00 0x01>;
+ };
+ dcin: adc-channel@2 {
+ reg = <0x00 0x02>;
+ };
+ ichg: adc-channel@3 {
+ reg = <0x00 0x03>;
+ };
+ vph_pwr: adc-channel@4 {
+ reg = <0x00 0x04>;
+ };
+ usb_vbus: adc-channel@a {
+ reg = <0x00 0x0a>;
+ };
+ die_temp: adc-channel@b {
+ reg = <0x00 0x0b>;
+ };
+ ref_625mv: adc-channel@c {
+ reg = <0x00 0x0c>;
+ };
+ ref_1250mv: adc-channel@d {
+ reg = <0x00 0x0d>;
+ };
+ ref_325mv: adc-channel@e {
+ reg = <0x00 0x0e>;
+ };
+ ref_muxoff: adc-channel@f {
+ reg = <0x00 0x0f>;
+ };
+};
+
+/* IIO client node */
+iio-hwmon {
+ compatible = "iio-hwmon";
+ io-channels = <&xoadc 0x00 0x01>, /* Battery */
+ <&xoadc 0x00 0x02>, /* DC in (charger) */
+ <&xoadc 0x00 0x04>, /* VPH the main system voltage */
+ <&xoadc 0x00 0x0b>, /* Die temperature */
+ <&xoadc 0x00 0x0c>, /* Reference voltage 1.25V */
+ <&xoadc 0x00 0x0d>, /* Reference voltage 0.625V */
+ <&xoadc 0x00 0x0e>; /* Reference voltage 0.325V */
+};