On 13/09/14 00:35, Hartmut Knaack wrote:
> Stanimir Varbanov schrieb, Am 11.09.2014 17:13:
>> Document DT binding for Qualcomm SPMI PMIC voltage ADC
>> driver.
>>
> Still one typo left.
>> Signed-off-by: Stanimir Varbanov <svarbanov@xxxxxxxxxx>
>> Signed-off-by: Ivan T. Ivanov <iivanov@xxxxxxxxxx>
>> ---
>> .../devicetree/bindings/iio/adc/qcom,spmi-vadc.txt | 123 ++++++++++++++++++++
>> 1 files changed, 123 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..5abb491
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt
>> @@ -0,0 +1,123 @@
>> +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: required
>> + Value type: <prop-encoded-array>
>> + Definition: End of convertion interrupt number.
> Typo: conversion
>> +
>> +- qcom,poll-eoc:
>> + Usage: optional
>> + Value type: <empty>
>> + Definition: Use polling instead of interrupt for end of conversion
>> + completion.
>> +
>> +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.
>> +
>> +- 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 one channel node is required.
Why? As far as I can see it will register all the channels anyway. If that is not the intent
you need to build the iio_chan_spec array rather than using a static one.
I'm fine with it providing channels with sensible defaults if they aren't overridden, but then
it should work fine with no channel nodes.
Jonathan
>> +
>> +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";
>> + };
>>
>
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