[alsa-devel] [RFC v2 2/7] IIO: Add bindings for simple sigma delta adc

[Arnaud Pouliquen]

Hello Rob,

Please find my answers in-line

Regards,

Arnaud

On 02/22/2017 04:17 PM, Rob Herring wrote:
> On Mon, Feb 13, 2017 at 05:38:24PM +0100, Arnaud Pouliquen wrote:
>> Add documentation of device tree bindings to support
>> sigma delta modulator in IIO framework.
>>
>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen at st.com>
>> ---
>>  Documentation/devicetree/bindings/iio/adc/simple_sd_adc.txt | 13 +++++++++++++
>>  1 file changed, 13 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/iio/adc/simple_sd_adc.txt
>>
>> diff --git a/Documentation/devicetree/bindings/iio/adc/simple_sd_adc.txt b/Documentation/devicetree/bindings/iio/adc/simple_sd_adc.txt
>> new file mode 100644
>> index 0000000..2b3968a
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/iio/adc/simple_sd_adc.txt
>> @@ -0,0 +1,13 @@
>> +Device-Tree bindings for simple sigma delta adc
> 
> What makes it "simple"?
"simple" sigma delta modulator are external chip that just converts
analog signal in sigma delta modulation. No configuration needs.
"Simple" is use to differentiate SD ADC that offers interfaces to
activate some internal processing ( gain, offset compensation...)

> 
>> +
>> +Required properties:
>> +- compatible: should be "sd-modulator".
>> +- #io-channel-cells = <1>: See the IIO bindings section "IIO consumers".
>> +
>> +Example node:
>> +
>> +	ads1202: simple_sd_adc at 0 {
> 
> Is ads1202 the actual chip? Then it should be in the compatible list.
I tried to define a generic device to support several SD modulator
chips, inspired by ALSA "dmic-codec" device.
I have none exhaustive list of chip that can be handled by the driver,
but i found several devices that could match...
That why i did not use chip name in compatible list.
What should be the best way to do it?

> 
> unit address without a reg prop is an error. The node name should be 
> "adc".
> 
>> +		compatible = "sd-modulator";
>> +		#io-channel-cells = <1>;
>> +		status = "okay";
> 
> Drop status from examples.
> 
>> +	};
>> -- 
>> 1.9.1
>>