| Qualcomm's QPNP PMIC current ADC driver |
| |
| QPNP PMIC current ADC (IADC) provides interface to clients to read |
| current. A 16 bit ADC is used for current measurements. There are multiple |
| peripherals to the IADC and the scope of the driver is to provide interface |
| for the USR peripheral of the IADC. |
| |
| IADC node |
| |
| Required properties: |
| - compatible : should be "qcom,qpnp-iadc" for Current ADC driver. |
| - reg : offset and length of the PMIC Arbiter register map. |
| - reg-names : resource names used for the physical base address of the PMIC IADC |
| peripheral, the SMBB_BAT_IF_TRIM_CNST_RDS register. |
| Should be "iadc-base" for the PMIC IADC peripheral base register. |
| Should be "batt-id-trim-cnst-rds" for reading the |
| SMBB_BAT_IF_TRIM_CNST_RDS register. |
| - address-cells : Must be one. |
| - size-cells : Must be zero. |
| - interrupts : The USR bank peripheral IADC interrupt. |
| - interrupt-names : Should contain "eoc-int-en-set". |
| - qcom,adc-bit-resolution : Bit resolution of the ADC. |
| - qcom,adc-vdd-reference : Voltage reference used by the ADC. |
| |
| Optional properties: |
| - qcom,rsense : Use this property when external rsense should be used |
| for current calculation and specify the units in nano-ohms. |
| - qcom,iadc-poll-eoc: Use polling instead of interrupts for End of Conversion completion. |
| - qcom,use-default-rds-trim : Add this property to check if certain conditions are to be checked |
| reading the SMBB_BAT_IF_CNST_RDS, IADC_RDS trim register and |
| manufacturer type. Check the driver for conditions that each of the type. |
| 0 : Select this type to read the IADC and SMBB trim register and |
| apply the default RSENSE if conditions are met. |
| 1 : Select this type to read the IADC, SMBB trim register and |
| manufacturer type and apply the default RSENSE if conditions are met. |
| - qcom,pmic-revid : Phandle pointing to the revision peripheral node. Use it to query the |
| PMIC type and revision for applying the appropriate temperature |
| compensation parameters. |
| |
| Channel node |
| NOTE: Atleast one Channel node is required. |
| |
| Client required property: |
| - qcom,<consumer name>-iadc : The phandle to the corresponding iadc device. |
| The consumer name passed to the driver when calling |
| qpnp_get_iadc() is used to associate the client |
| with the corresponding device. |
| |
| Required properties: |
| - label : Channel name used for sysfs entry. |
| - reg : AMUX channel number. |
| - qcom,channel-num : Channel number associated to the AMUX input. |
| - qcom,decimation : Sampling rate to use for the individual channel measurement. |
| Select from the following unsigned int. |
| 0 : 512 |
| 1 : 1K |
| 2 : 2K |
| 3 : 4K |
| - qcom,pre-div-channel-scaling : Pre-div used for the channel before the signal |
| is being measured. |
| - qcom,calibration-type : Calibration point values vary with temperature. |
| For improved accuracy fresh gain and offset point values |
| can be used for calibration. Reading fresh values for ever |
| read affects the reading time. Application can use the historic |
| values used from the trim register values. |
| Select from the following strings. |
| "absolute" : Uses TRIM gain and offset values for calibration. |
| "ratiometric" : Calculate the gain and offset calibration value when an ADC |
| request is issued. |
| - qcom,scale-function : Scaling fuction used to convert raw ADC code to units specific to |
| a given channel. |
| Select from the following unsigned int. |
| 0 : Default scaling to convert raw adc code to voltage. |
| 1 : Conversion to temperature based on btm parameters. |
| 2 : Returns result in milli degree's Centigrade. |
| 3 : Returns current across 0.1 ohm resistor. |
| 4 : Returns XO thermistor voltage in degree's Centigrade. |
| - qcom,hw-settle-time : Settling period for the channel before ADC read. |
| Select from the following unsigned int. |
| 0 : 0us |
| 1 : 100us |
| 2 : 200us |
| 3 : 300us |
| 4 : 400us |
| 5 : 500us |
| 6 : 600us |
| 7 : 700us |
| 8 : 800us |
| 9 : 900us |
| 0xa : 1ms |
| 0xb : 2ms |
| 0xc : 4ms |
| 0xd : 6ms |
| 0xe : 8ms |
| 0xf : 10ms |
| - qcom,fast-avg-setup : Average 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) |
| Select from the following unsigned int. |
| 0 : 1 |
| 1 : 2 |
| 2 : 4 |
| 3 : 8 |
| 4 : 16 |
| 5 : 32 |
| 6 : 64 |
| 7 : 128 |
| 8 : 256 |
| - qcom,iadc-vadc : Corresponding phandle of the VADC device to read the die_temperature and set |
| simultaneous voltage and current conversion requests. |
| |
| Example: |
| /* Main Node */ |
| qcom,iadc@3200 { |
| compatible = "qcom,qpnp-iadc"; |
| reg = <0x3200 0x100>; |
| #address-cells = <1>; |
| #size-cells = <0>; |
| interrupts = <0 0x36 0>; |
| interrupt-names = "eoc-int-en-set"; |
| qcom,adc-bit-resolution = <16>; |
| qcom,adc-vdd-reference = <1800>; |
| qcom,rsense = <1500>; |
| qcom,iadc-vadc = <&pm8941_vadc>; |
| |
| /* Channel Node */ |
| chan@0 = { |
| label = "rsense"; |
| reg = <0>; |
| qcom,decimation = <0>; |
| qcom,pre-div-channel-scaling = <20>; |
| qcom,calibration-type = "fresh"; |
| qcom,scale-function = <0>; |
| qcom,hw-settle-time = <0>; |
| qcom,fast-avg-setup = <0>; |
| }; |
| }; |
| |
| Client device example: |
| /* Add to the clients node that needs the IADC */ |
| client_node { |
| qcom,client-iadc = <&pm8941_iadc>; |
| }; |