dt-bindings: mfd: Add STM32 LPTimer binding

Add documentation for STMicroelectronics STM32 Low-Power Timer 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/mfd/stm32-lptimer.txt b/Documentation/devicetree/bindings/mfd/stm32-lptimer.txt
new file mode 100644 (file)
index 0000000..2a9ff29
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+++ b/Documentation/devicetree/bindings/mfd/stm32-lptimer.txt
@@ -0,0 +1,48 @@
+STMicroelectronics STM32 Low-Power Timer
+
+The STM32 Low-Power Timer (LPTIM) is a 16-bit timer that provides several
+functions:
+- PWM output (with programmable prescaler, configurable polarity)
+- Quadrature encoder, counter
+- Trigger source for STM32 ADC/DAC (LPTIM_OUT)
+
+Required properties:
+- compatible:          Must be "st,stm32-lptimer".
+- reg:                 Offset and length of the device's register set.
+- clocks:              Phandle to the clock used by the LP Timer module.
+- clock-names:         Must be "mux".
+- #address-cells:      Should be '<1>'.
+- #size-cells:         Should be '<0>'.
+
+Optional subnodes:
+- pwm:                 See ../pwm/pwm-stm32-lp.txt
+- counter:             See ../iio/timer/stm32-lptimer-cnt.txt
+- trigger:             See ../iio/timer/stm32-lptimer-trigger.txt
+
+Example:
+
+       timer@40002400 {
+               compatible = "st,stm32-lptimer";
+               reg = <0x40002400 0x400>;
+               clocks = <&timer_clk>;
+               clock-names = "mux";
+               #address-cells = <1>;
+               #size-cells = <0>;
+
+               pwm {
+                       compatible = "st,stm32-pwm-lp";
+                       pinctrl-names = "default";
+                       pinctrl-0 = <&lppwm1_pins>;
+               };
+
+               trigger@0 {
+                       compatible = "st,stm32-lptimer-trigger";
+                       reg = <0>;
+               };
+
+               counter {
+                       compatible = "st,stm32-lptimer-counter";
+                       pinctrl-names = "default";
+                       pinctrl-0 = <&lptim1_in_pins>;
+               };
+       };