dt-bindings: iio: imu: st_lsm6dsx: support open drain mode

Signed-off-by: NLorenzo Bianconi <lorenzo.bianconi@st.com>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Documentation/devicetree/bindings/iio/imu/st_lsm6dsx.txt

@@ -11,6 +11,14 @@ Required properties:
 Optional properties:
 - st,drdy-int-pin: the pin on the package that will be used to signal
   "data ready" (valid values: 1 or 2).
+- drive-open-drain: the interrupt/data ready line will be configured
+  as open drain, which is useful if several sensors share the same
+  interrupt line. This is a boolean property.
+  (This binding is taken from pinctrl/pinctrl-bindings.txt)
+  If the requested interrupt is configured as IRQ_TYPE_LEVEL_HIGH or
+  IRQ_TYPE_EDGE_RISING a pull-down resistor is needed to drive the line
+  when it is not active, whereas a pull-up one is needed when interrupt
+  line is configured as IRQ_TYPE_LEVEL_LOW or IRQ_TYPE_EDGE_FALLING.
 - interrupt-parent: should be the phandle for the interrupt controller
 - interrupts: interrupt mapping for IRQ. It should be configured with
   flags IRQ_TYPE_LEVEL_HIGH, IRQ_TYPE_EDGE_RISING, IRQ_TYPE_LEVEL_LOW or