dt-bindings: iio: dac: add bindings for ltc1660

LTC1665/LTC1660 is a 8/10-bit Digital-to-Analog Converter (DAC)
with eight individual channels.

Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/Documentation/devicetree/bindings/iio/dac/ltc1660.txt b/Documentation/devicetree/bindings/iio/dac/ltc1660.txt
new file mode 100644 (file)
index 0000000..c5b5f22
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/dac/ltc1660.txt
@@ -0,0 +1,21 @@
+* Linear Technology Micropower octal 8-Bit and 10-Bit DACs
+
+Required properties:
+ - compatible: Must be one of the following:
+               "lltc,ltc1660"
+               "lltc,ltc1665"
+ - reg: SPI chip select number for the device
+ - vref-supply: Phandle to the voltage reference supply
+
+Recommended properties:
+ - spi-max-frequency: Definition as per
+        Documentation/devicetree/bindings/spi/spi-bus.txt.
+        Max frequency for this chip is 5 MHz.
+
+Example:
+dac@0 {
+       compatible = "lltc,ltc1660";
+       reg = <0>;
+       spi-max-frequency = <5000000>;
+       vref-supply = <&vref_reg>;
+};