Document DT binding for Qualcomm SPMI PMIC voltage ADC driver. Signed-off-by: Stanimir Varbanov <svarbanov@xxxxxxxxxx> Signed-off-by: Ivan T. Ivanov <iivanov@xxxxxxxxxx> --- .../devicetree/bindings/iio/adc/qcom,spmi-vadc.txt | 130 ++++++++++++++++++++ 1 files changed, 130 insertions(+), 0 deletions(-) create mode 100644 Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt diff --git a/Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt b/Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt new file mode 100644 index 0000000..fa30300 --- /dev/null +++ b/Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt @@ -0,0 +1,130 @@ +Qualcomm's SPMI PMIC voltage ADC + +SPMI PMIC voltage ADC (VADC) provides interface to clients to read +voltage. A 15 bit ADC is used for voltage measurements. There are multiple +peripherals to the VADC and the scope of the driver is to provide interface +for the USR peripheral of the VADC. + +VADC node: + +- compatible: + Usage: required + Value type: <string> + Definition: Should contain "qcom,spmi-vadc". + +- reg: + Usage: required + Value type: <u32> + Definition: Base address in the SPMI PMIC register map. + +- address-cells: + Usage: required + Value type: <u32> + Definition: Must be one. + +- size-cells: + Usage: required + Value type: <u32> + Definition: Must be zero. + +- interrupts: + Usage: optional + Value type: <prop-encoded-array> + Definition: End of conversion interrupt number. If this property does + not exist polling will be used instead. + +- interrupt-names: + Usage: optional + Value type: <string> + Definition: Should contain the interrupt name "eoc" (end of conversion). + +Channel node properties: + +- reg: + Usage: required + Value type: <u32> + Definition: AMUX channel number. + See include/dt-bindings/iio/qcom,spmi-pmic-vadc.h + +- qcom,decimation: + Usage: optional + Value type: <u32> + Definition: Sampling rate to use for the individual channel measurement. + Quicker measurements can be made by reducing decimation ratio. + Valid values are 512, 1024, 2048, 4096. + If property is not found, default value of 512 will be used. + +- qcom,pre-scaling: + Usage: optional + Value type: <u32 array> + Definition: Used for scaling the channel input signal before the signal is + fed to VADC. The configuration for this node is to know the + pre-determined ratio and use it for post scaling. Select one from + the following options. + <1 1>, <1 3>, <1 4>, <1 6>, <1 20>, <1 8>, <10 81>, <1 10> + If property is not found default value depending of chip will be used. + +- qcom,ratiometric: + Usage: optional + 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 property is not found, channel will be + calibrated with 625mV and 1.25V reference channels. + Otherwise the absolute calibration will be used. + +- qcom,hw-settle-time: + Usage: optional + Value type: <u32> + Definition: Time between AMUX getting configured and the ADC starting + conversion. Delay = 100us * (value) for value < 11, and + 2ms * (value - 10) otherwise. + Valid values are: 0, 100, 200, 300, 400, 500, 600, 700, 800, + 900 us and 1, 2, 4, 6, 8, 10 ms + If property is not found, channel will use 0us. + +- qcom,avg-samples: + Usage: optional + Value type: <u32> + Definition: Number of samples to be used for measurement. + Fast averaging provides the option to obtain a single measurement + from the ADC that is an average of multiple samples. The value + selected is 2^(value). + Valid values are: 1, 2, 4, 8, 16, 32, 64, 128, 256, 512 + If property is not found, 1 sample will be used. + +NOTE: At least reference channel nodes are required. The reference channels + might be different depending on PMIC version. + Reference channels per type of calibration are: + - absolute + (VADC_REF_625MV or VADC_SPARE1) and VADC_REF_1250MV + - ratiomatric + VADC_GND_REF and VADC_VDD_VADC + +Example: + /* VADC node */ + pmic_vadc: vadc@3100 { + compatible = "qcom,spmi-vadc"; + reg = <0x3100 0x100>; + interrupts = <0x0 0x31 0x0 IRQ_TYPE_EDGE_RISING>; + #address-cells = <1>; + #size-cells = <0>; + #io-channel-cells = <1>; + io-channel-ranges; + + /* Channel node */ + usb_id_nopull { + reg = <VADC_LR_MUX10_USB_ID>; + qcom,decimation = <512>; + qcom,ratiometric; + qcom,hw-settle-time = <200>; + qcom,avg-samples = <1>; + qcom,pre-scaling = <1 3>; + }; + }; + + /* IIO client node */ + usb { + io-channels = <&pmic_vadc VADC_LR_MUX10_USB_ID>; + io-channel-names = "vadc"; + }; -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html