dt-bindings: iio: Add STM32 LPTimer trigger binding

Add documentation for STMicroelectronics STM32 Low-Power Timer Trigger
binding.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/Documentation/devicetree/bindings/iio/timer/stm32-lptimer-trigger.txt b/Documentation/devicetree/bindings/iio/timer/stm32-lptimer-trigger.txt
new file mode 100644 (file)
index 0000000..85e6806
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/timer/stm32-lptimer-trigger.txt
@@ -0,0 +1,23 @@
+STMicroelectronics STM32 Low-Power Timer Trigger
+
+STM32 Low-Power Timer provides trigger source (LPTIM output) that can be used
+by STM32 internal ADC and/or DAC.
+
+Must be a sub-node of an STM32 Low-Power Timer device tree node.
+See ../mfd/stm32-lptimer.txt for details about the parent node.
+
+Required properties:
+- compatible:          Must be "st,stm32-lptimer-trigger".
+- reg:                 Identify trigger hardware block. Must be 0, 1 or 2
+                       respectively for lptimer1, lptimer2 or lptimer3
+                       trigger output.
+
+Example:
+       timer@40002400 {
+               compatible = "st,stm32-lptimer";
+               ...
+               trigger@0 {
+                       compatible = "st,stm32-lptimer-trigger";
+                       reg = <0>;
+               };
+       };