dt-bindings: iio: adc: tlc4541 - recover accidentally dropped binding doc

JC: Seems that I messed up applying the original driver patches, and
this file never actually made it into the tree.

I have picked up original Ack and Sign-off so as to record the
history.

Signed-off-by: Phil Reid <preid@electromag.com.au>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20200809111753.156236-13-jic23@kernel.org

diff --git a/Documentation/devicetree/bindings/iio/adc/ti-tlc4541.txt b/Documentation/devicetree/bindings/iio/adc/ti-tlc4541.txt
new file mode 100644 (file)
index 0000000..6b26927
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/ti-tlc4541.txt
@@ -0,0 +1,17 @@
+* Texas Instruments' TLC4541
+
+Required properties:
+ - compatible: Should be one of
+       * "ti,tlc4541"
+       * "ti,tlc3541"
+       - reg: SPI chip select number for the device
+ - vref-supply: The regulator supply for ADC reference voltage
+ - spi-max-frequency: Max SPI frequency to use (<= 200000)
+
+Example:
+adc@0 {
+       compatible = "ti,tlc4541";
+       reg = <0>;
+       vref-supply = <&vdd_supply>;
+       spi-max-frequency = <200000>;
+};