iio: distance: add dt binding for devantech-srf04
This patch adds dt binding for devantech ultrasonic ranger srf04.
The vendor "devantech" was already added to the vendor list with
"[PATCH v4 1/3] iio: distance: srf08: add trivial DT binding"
Signed-off-by: Andreas Klinger <ak@it-klinger.de>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/Documentation/devicetree/bindings/iio/proximity/devantech-srf04.txt b/Documentation/devicetree/bindings/iio/proximity/devantech-srf04.txt
new file mode 100644
index 0000000..d4dc7a2
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/proximity/devantech-srf04.txt
@@ -0,0 +1,28 @@
+* Devantech SRF04 ultrasonic range finder
+ Bit-banging driver using two GPIOs
+
+Required properties:
+ - compatible: Should be "devantech,srf04"
+
+ - trig-gpios: Definition of the GPIO for the triggering (output)
+ This GPIO is set for about 10 us by the driver to tell the
+ device it should initiate the measurement cycle.
+
+ - echo-gpios: Definition of the GPIO for the echo (input)
+ This GPIO is set by the device as soon as an ultrasonic
+ burst is sent out and reset when the first echo is
+ received.
+ Thus this GPIO is set while the ultrasonic waves are doing
+ one round trip.
+ It needs to be an GPIO which is able to deliver an
+ interrupt because the time between two interrupts is
+ measured in the driver.
+ See Documentation/devicetree/bindings/gpio/gpio.txt for
+ information on how to specify a consumer gpio.
+
+Example:
+srf04@0 {
+ compatible = "devantech,srf04";
+ trig-gpios = <&gpio1 15 GPIO_ACTIVE_HIGH>;
+ echo-gpios = <&gpio2 6 GPIO_ACTIVE_HIGH>;
+};
