Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 41 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/iio/dac/dpot-dac.txt b/Documentation/devicetree/bindings/iio/dac/dpot-dac.txt
new file mode 100644
index 000000000..fdf47a01b
--- /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";
+	};