dt-bindings: iio: document dpot-dac bindings

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/Documentation/devicetree/bindings/iio/dac/dpot-dac.txt b/Documentation/devicetree/bindings/iio/dac/dpot-dac.txt
new file mode 100644 (file)
index 0000000..fdf47a0
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/dac/dpot-dac.txt
@@ -0,0 +1,41 @@
+Bindings for DAC emulation using a digital potentiometer
+
+It is assumed that the dpot is used as a voltage divider between the
+current dpot wiper setting and the maximum resistance of the dpot. The
+divided voltage is provided by a vref regulator.
+
+                  .------.
+   .-----------.  |      |
+   | vref      |--'    .---.
+   | regulator |--.    |   |
+   '-----------'  |    | d |
+                  |    | p |
+                  |    | o |  wiper
+                  |    | t |<---------+
+                  |    |   |
+                  |    '---'       dac output voltage
+                  |      |
+                  '------+------------+
+
+Required properties:
+- compatible: Should be "dpot-dac"
+- vref-supply: The regulator supplying the voltage divider.
+- io-channels: Channel node of the dpot to be used for the voltage division.
+- io-channel-names: Should be "dpot".
+
+Example:
+
+       &i2c {
+               dpot: mcp4651-503@28 {
+                       compatible = "microchip,mcp4651-503";
+                       reg = <0x28>;
+                       #io-channel-cells = <1>;
+               };
+       };
+
+       dac {
+               compatible = "dpot-dac";
+               vref-supply = <&reg_3v3>;
+               io-channels = <&dpot 0>;
+               io-channel-names = "dpot";
+       };

diff --git a/MAINTAINERS b/MAINTAINERS
index 1395246..0de0673 100644 (file)
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6119,6 +6119,12 @@ L:       linux-media@vger.kernel.org
 S:     Maintained
 F:     drivers/media/rc/iguanair.c
 
+IIO DIGITAL POTENTIOMETER DAC
+M:     Peter Rosin <peda@axentia.se>
+L:     linux-iio@vger.kernel.org
+S:     Maintained
+F:     Documentation/devicetree/bindings/iio/dac/dpot-dac.txt
+
 IIO SUBSYSTEM AND DRIVERS
 M:     Jonathan Cameron <jic23@kernel.org>
 R:     Hartmut Knaack <knaack.h@gmx.de>