[PATCH v3 2/2] dt-bindings: iio: dac: Add docs for AD5758 DAC

Signed-off-by: Stefan Popa --- Changes in v3: - AD5758 can be both a current and voltage output DAC. The decision is made based on the DT and the channel type is set during probe. - range was replaced by range-microvolt and range-microamp - dc-dc-mode,

[PATCH v3 2/2] dt-bindings: iio: dac: Add docs for AD5758 DAC

Signed-off-by: Stefan Popa --- Changes in v3: - AD5758 can be both a current and voltage output DAC. The decision is made based on the DT and the channel type is set during probe. - range was replaced by range-microvolt and range-microamp - dc-dc-mode,