pwm: sti: Supply Device Tree binding documentation for ST's PWM IP

Signed-off-by: Ajit Pal Singh <ajitpal.singh@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

1 files changed, 41 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/pwm/pwm-st.txt b/Documentation/devicetree/bindings/pwm/pwm-st.txt
new file mode 100644
index 000000000000..84d2fb807d3c
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/pwm-st.txt
@@ -0,0 +1,41 @@
+STMicroelectronics PWM driver bindings
+--------------------------------------
+
+Required parameters:
+- compatible :          "st,pwm"
+- #pwm-cells :          Number of cells used to specify a PWM. First cell
+                        specifies the per-chip index of the PWM to use and the
+                        second cell is the period in nanoseconds - fixed to 2
+                        for STiH41x.
+- reg :                 Physical base address and length of the controller's
+                        registers.
+- pinctrl-names:        Set to "default".
+- pinctrl-0:            List of phandles pointing to pin configuration nodes
+                        for PWM module.
+                        For Pinctrl properties, please refer to [1].
+- clock-names:          Set to "pwm".
+- clocks:               phandle of the clock used by the PWM module.
+                        For Clk properties, please refer to [2].
+
+Optional properties:
+- st,pwm-num-chan:      Number of available channels. If not passed, the driver
+                        will consider single channel by default.
+
+[1] Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
+[2] Documentation/devicetree/bindings/clock/clock-bindings.txt
+
+Example:
+
+pwm1: pwm@fe510000 {
+        compatible = "st,pwm";
+        reg = <0xfe510000 0x68>;
+        #pwm-cells = <2>;
+        pinctrl-names = "default";
+        pinctrl-0 = <&pinctrl_pwm1_chan0_default
+                     &pinctrl_pwm1_chan1_default
+                     &pinctrl_pwm1_chan2_default
+                     &pinctrl_pwm1_chan3_default>;
+        clocks = <&clk_sysin>;
+        clock-names = "pwm";
+        st,pwm-num-chan = <4>;
+};