[PATCH 1/3 v2] iio: adc: add device tree bindings for Qualcomm PM8xxx ADCs

[Rob Herring]

On Thu, Dec 15, 2016 at 11:48:09PM +0100, Linus Walleij wrote:
> This adds the device tree bindings for the Qualcomm PM8xxx
> ADCs. This is based on the existing DT bindings for the
> SPMI ADC so there are hopefully no controversial features.
> 
> Cc: devicetree at vger.kernel.org
> Cc: linux-arm-kernel at lists.infradead.org
> Cc: linux-arm-msm at vger.kernel.org
> Cc: Ivan T. Ivanov <iivanov.xz at gmail.com>
> Cc: Andy Gross <andy.gross at linaro.org>
> Cc: Bjorn Andersson <bjorn.andersson at linaro.org>
> Cc: Stephen Boyd <sboyd at codeaurora.org>
> Cc: Srinivas Kandagatla <srinivas.kandagatla at linaro.org>
> Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
> ---
> ChangeLog v1->v2:
> - Spelling fixes
> ---
>  .../bindings/iio/adc/qcom,pm8xxx-xoadc.txt         | 160 +++++++++++++++++++++
>  1 file changed, 160 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/qcom,pm8xxx-xoadc.txt
> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/qcom,pm8xxx-xoadc.txt b/Documentation/devicetree/bindings/iio/adc/qcom,pm8xxx-xoadc.txt
> new file mode 100644
> index 000000000000..3c6bca5b4edf
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/qcom,pm8xxx-xoadc.txt
> @@ -0,0 +1,160 @@
> +Qualcomm's PM8xxx voltage XOADC
> +
> +The Qualcomm PM8xxx PMICs contain a HK/XO ADC (Housekeeping/Crystal
> +oscillator ADC) encompassing PM8018, PM8038, PM8058, PM8917 and PM8921.
> +
> +Required properties:
> +
> +- compatible: should be one of:
> +  "qcom,pm8018-adc"
> +  "qcom,pm8038-adc"
> +  "qcom,pm8058-adc"
> +  "qcom,pm8917-adc"
> +  "qcom,pm8921-adc"
> +
> +- reg: should contain the ADC base address in the PMIC, typically
> +  0x197.
> +
> +The following required properties are standard for IO channels, see
> +iio-bindings.txt for more details:
> +
> +- #address-cells: should be set to <1>
> +
> +- #size-cells: should be set to <0>
> +
> +- #io-channel-cells: should be set to <1>
> +
> +- 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:
> +
> +ref_625mv {

ref at c

> +	reg = <0x0c>;
> +};
> +
> +ref_1250mv {
> +	reg = <0x0d>;
> +};
> +
> +ref_muxoff {
> +	reg = <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 channel 0x0c, 0x0d and
> +0x0f are optional.
> +
> +Required channel node properties:
> +
> +- reg: should contain the hardware channel number in the range
> +  0 .. 0x0f (4 bits). The hardware only supports 16 channels.
> +
> +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: <empty>
> +  Definition: Channel calibration type. If this property is specified
> +          VADC will use the VDD reference (1.8V) and GND for channel
> +          calibration. 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.
> +
> +- qcom,ratiometric-ref:
> +  Value type: <u32>
> +  Definition: The reference voltage pair 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 at 197 {
> +	compatible = "qcom,pm8058-adc";
> +	reg = <0x197>;
> +	interrupt-parent = <&pm8058>;
> +	interrupts = <76 1>;
> +	#address-cells = <1>;
> +	#size-cells = <0>;
> +	#io-channel-cells = <1>;
> +
> +	vcoin {
> +		reg = <0x00>;

If you have a reg property, then you should have a unit address on all 
of these.

These should really all be something like adc-channel at ... Not sure if we 
have a standard node name for ADC channels. Or don't put any of this in 
DT.

> +	};
> +	vbat {
> +		reg = <0x01>;
> +	};
> +	dcin {
> +		reg = <0x02>;
> +	};
> +	ichg {
> +		reg = <0x03>;
> +	};
> +	vph_pwr {
> +		reg = <0x04>;
> +	};
> +	mpp5 {
> +		reg = <0x05>;
> +	};
> +	mpp6 {
> +		reg = <0x06>;
> +	};
> +	mpp7 {
> +		reg = <0x07>;
> +	};
> +	mpp8 {
> +		reg = <0x08>;
> +	};
> +	mpp9 {
> +		reg = <0x09>;
> +	};
> +	usb_vbus {
> +		reg = <0x0a>;
> +	};
> +	die_temp {
> +		reg = <0x0b>;
> +	};
> +	ref_625mv {
> +		reg = <0x0c>;
> +	};
> +	ref_1250mv {
> +		reg = <0x0d>;
> +	};
> +	ref_325mv {
> +		reg = <0x0e>;
> +	};
> +	ref_muxoff {
> +		reg = <0x0f>;
> +	};
> +};