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

From: Mark Rutland
Date: Mon Oct 12 2015 - 11:19:26 EST


On Mon, Oct 12, 2015 at 01:50:32PM +0200, Paul Cercueil wrote:
> Signed-off-by: Paul Cercueil <paul.cercueil@xxxxxxxxxx>
> ---
> .../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.
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