Re: [PATCH v2 11/14] staging: iio: ad7746: Add devicetree bindings documentation

[Jonathan Cameron]

On Fri, 13 Apr 2018 13:36:48 -0300
HernÃn Gonzalez <hernan@xxxxxxxxxxxxxxxxxxxx> wrote:

> Cc: Rob Herring <robh+dt@xxxxxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Cc: devicetree@xxxxxxxxxxxxxxx
> Signed-off-by: HernÃn Gonzalez <hernan@xxxxxxxxxxxxxxxxxxxx>
A few comments inline.

Thanks,

Jonathan

> ---
>  .../devicetree/bindings/staging/iio/cdc/ad7746.txt | 34 ++++++++++++++++++++++
>  1 file changed, 34 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/staging/iio/cdc/ad7746.txt
> 
> diff --git a/Documentation/devicetree/bindings/staging/iio/cdc/ad7746.txt b/Documentation/devicetree/bindings/staging/iio/cdc/ad7746.txt
> new file mode 100644
> index 0000000..7740f05
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/staging/iio/cdc/ad7746.txt
> @@ -0,0 +1,34 @@
> +Analog Devices AD7746/5/7 capacitive sensor driver
> +
> +Required properties:
> +	- compatible: Should be one of
> +		* "adi,ad7745"
> +		* "adi,ad7746"
> +	  * "adi,ad7747"
> +	- reg: The 7-bits long I2c address of the device
> +
> +Optional properties:
> +	- adi,exclvl: This property defines the excitation voltage level for the
> +    capacitance to be measured. Possible values are:
> +      * 0 = +-VDD/8
> +      * 1 = +-VDD/4
> +      * 2 = +-VDD * 3/8
> +      * 3 = +-VDD/2 (Default)
> +	- adi,nexca_en: Invert excitation output A.

The naming is rather odd.  Why _en?

> +	- adi,nexcb_en:	Invert excitation output B.
> +
> +Example:
> +Here exclvl would be 1 (VDD/4), Excitation pin A would be inverted and
> +Excitation pin B would NOT be inverted.
> +
> +i2c2 {
> +
> +      < . . . >
What does this spacer add to the example?
Sure, there can be other devices, but no need to illustrate that here.

> +
> +      ad7746: ad7746@60 {
> +              compatible = "ad7746";
> +              reg = <0x60>;
> +              adi,exclvl = <1>;
> +              adi,nexca_en;
> +      };
> +};