Signed-off-by: Peter Rosin <peda@xxxxxxxxxx>
---
.../bindings/iio/adc/envelope-detector.txt | 65 ++++++++++++++++++++++
MAINTAINERS | 6 ++
2 files changed, 71 insertions(+)
create mode 100644 Documentation/devicetree/bindings/iio/adc/envelope-detector.txt
diff --git a/Documentation/devicetree/bindings/iio/adc/envelope-detector.txt b/Documentation/devicetree/bindings/iio/adc/envelope-detector.txt
new file mode 100644
index 000000000000..0e26299516fd
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/envelope-detector.txt
@@ -0,0 +1,65 @@
+Bindings for ADC envelope detector using a DAC and a comparator
+
+The DAC is used to find the peak level of an alternating voltage input
+signal by a binary search using the output of a comparator wired to
+an interrupt pin. Like so:
+ _
+ | \
+ input +------>-------|+ \
+ | \
+ .-------. | }---.
+ | | | / |
+ | dac|-->--|- / |
+ | | |_/ |
+ | | |
+ | | |
+ | irq|------<-------'
+ | |
+ '-------'
+
+Required properties:
+- compatible: Should be "envelope-detector"
+- io-channels: Channel node of the dac to be used for comparator input.
+- io-channel-names: Should be "dac".
+- interrupt specification for one client interrupt,
+ see ../../interrupt-controller/interrupts.txt for details.
+- interrupt-names: Should be "comp".
+- envelope-detector,dac-max: The maximum raw input value for the dac.
+- envelope-detector,comp-interval-ms: How long to wait for the comparator
+ to trigger before moving on to another DAC level. This interval needs to
+ relate to the lowest possible frequency of the above input signal.
+
+Optional properties:
+- envelope-detector,inverted: If the input signal is centered around the
+ dac-max voltage (instead of zero), this property causes the detector to
+ search for the lowest DAC value that does not triggers the comparator
+ (instead of the highest). The result is also inverted so that a lower DAC
+ reading yields a higher voltage value.
+
+
+Example:
+
+ &spi {
+ dac: ad7303@4 {
+ compatible = "adi,ad7303";
+ reg = <4>;
+ spi-max-frequency = <10000000>;
+ Vdd-supply = <&vdd_supply>;
+ adi,use-external-reference;
+ REF-supply = <&vref_supply>;
+ #io-channel-cells = <1>;
+ };
+ };
+
+ envelope-detector {
+ compatible = "envelope-detector";
+ io-channels = <&dac 0>;
+ io-channel-names = "dac";
+
+ interrupt-parent = <&gpio>;
+ interrupts = <3 IRQ_TYPE_EDGE_FALLING>;
+ interrupt-names = "comp";
+
+ envelope-detector,dac-max = <255>;
+ envelope-detector,comp-interval-ms = <50>;
+ };
diff --git a/MAINTAINERS b/MAINTAINERS
index 8c8aae24b96b..4b6f6ec1b703 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6118,6 +6118,12 @@ S: Maintained
F: Documentation/devicetree/bindings/iio/dac/dpot-dac.txt
F: drivers/iio/dac/dpot-dac.c
+IIO ENVELOPE DETECTOR
+M: Peter Rosin <peda@xxxxxxxxxx>
+L: linux-iio@xxxxxxxxxxxxxxx
+S: Maintained
+F: Documentation/devicetree/bindings/iio/adc/envelope-detector.txt
+
IIO SUBSYSTEM AND DRIVERS
M: Jonathan Cameron <jic23@xxxxxxxxxx>
R: Hartmut Knaack <knaack.h@xxxxxx>
--
2.1.4
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