pwm: vt8500: Update vt8500 PWM driver support

This patch updates pwm-vt8500.c to support devicetree probing and
make use of the common clock subsystem.

A binding document describing the PWM controller found on
arch-vt8500 is also included.

Signed-off-by: Tony Prisk <linux@prisktech.co.nz>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

1 files changed, 17 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/pwm/vt8500-pwm.txt b/Documentation/devicetree/bindings/pwm/vt8500-pwm.txt
new file mode 100644
index 000000000000..bcc63678a9a5
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/vt8500-pwm.txt
@@ -0,0 +1,17 @@
+VIA/Wondermedia VT8500/WM8xxx series SoC PWM controller
+
+Required properties:
+- compatible: should be "via,vt8500-pwm"
+- reg: physical base address and length of the controller's registers
+- #pwm-cells: should be 2.  The first cell specifies the per-chip index
+  of the PWM to use and the second cell is the period in nanoseconds.
+- clocks: phandle to the PWM source clock
+
+Example:
+
+pwm1: pwm@d8220000 {
+        #pwm-cells = <2>;
+        compatible = "via,vt8500-pwm";
+        reg = <0xd8220000 0x1000>;
+        clocks = <&clkpwm>;
+};