Re: [PATCHv2 1/3] Documentation: ad5064: Added devicetree bindings documentation

[Mark Rutland <mark.rutland@arm.com>]

On Mon, Oct 12, 2015 at 01:50:32PM +0200, Paul Cercueil wrote:
> Signed-off-by: Paul Cercueil <paul.cercueil@analog.com>
> ---
>  .../devicetree/bindings/iio/dac/ad5064.txt         | 48 ++++++++++++++++++++++
>  1 file changed, 48 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/dac/ad5064.txt
> 
>  v2: No change in this patch
> 
> diff --git a/Documentation/devicetree/bindings/iio/dac/ad5064.txt b/Documentation/devicetree/bindings/iio/dac/ad5064.txt
> new file mode 100644
> index 0000000..fa2d328
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/dac/ad5064.txt
> @@ -0,0 +1,48 @@
> +Analog Devices AD5064 DAC device driver
> +
> +Required properties:
> +	- compatible: Must be one of:
> +		* "adi,ad5024"
> +		* "adi,ad5025"
> +		* "adi,ad5044"
> +		* "adi,ad5045"
> +		* "adi,ad5064"
> +		* "adi,ad5064-1"
> +		* "adi,ad5065"
> +		* "adi,ad5628-1"
> +		* "adi,ad5628-2"
> +		* "adi,ad5648-1"
> +		* "adi,ad5648-2"
> +		* "adi,ad5666-1"
> +		* "adi,ad5666-2"
> +		* "adi,ad5668-1"
> +		* "adi,ad5668-2"
> +		* "adi,ad5668-3"
> +	- reg: SPI chip select number for the device
> +	- spi-max-frequency: Max SPI frequency to use (< 30000000)
> +	- vrefA-supply, vrefB-supply: phandles to external reference voltage
> +	  supplies for channels 0 and 1 respectively.
> +	  This property must be present for ad5024, ad5025, ad5044, ad5045,
> +	  ad5064, ad5065.
> +	- vrefC-supply, vrefD-supply: phandles to external reference voltage
> +	  supplies for channels 2 and 3 respectively.
> +	  This property must be present for ad5024, ad5044, ad5064.

Nit: please don't use CamelCase property names. just have vref-a-supply
and so on.

> +
> +Optional properties:
> +	- vref-supply: phandle to the external reference voltage supply.
> +	  This should only be set if there is an external reference voltage
> +	  connected to the vref or vref[A-D] pins.

I don't understand. Surely the latter case means you're describing the
same supply twice (as it should already be in vref*-supply)?

What vref pins does the HW actually have?

> +	  If the property is not set, the internal reference voltage supply
> +	  is used if present.
> +	  This property can be used with ad5064-1, ad5628-1, ad5628-2, ad5648-1,
> +	  ad5648-2, ad5666-1, ad5666-2, ad5668-1, ad5668-2, ad5668-3.
> +
> +Example:
> +
> +		ad5668-2@4 {
> +			compatible = "adi,ad5668-2";
> +			reg = <4>;
> +			spi-max-frequency = <10000000>;
> +			adi,use-external-reference;

This is undocumented (and unused by the driver?).

Thanks,
Mark.