phy: phy-stih407-usb: Add dt documentation for USB picophy found on stih407 SoC family

This patch adds the dt documentation for the usb picophy found on stih407 SoC family
available from STMicroelectronics.

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

diff --git a/Documentation/devicetree/bindings/phy/phy-stih407-usb.txt b/Documentation/devicetree/bindings/phy/phy-stih407-usb.txt
new file mode 100644 (file)
index 0000000..1ef8228
--- /dev/null
+++ b/Documentation/devicetree/bindings/phy/phy-stih407-usb.txt
@@ -0,0 +1,30 @@
+ST STiH407 USB PHY controller
+
+This file documents the dt bindings for the usb picoPHY driver which is the PHY for both USB2 and USB3
+host controllers (when controlling usb2/1.1 devices) available on STiH407 SoC family from STMicroelectronics.
+
+Required properties:
+- compatible           : should be "st,stih407-usb2-phy"
+- reg                  : contain the offset and length of the system configuration registers
+                         used as glue logic to control & parameter phy
+- reg-names            : the names of the system configuration registers in "reg", should be "param" and "reg"
+- st,syscfg            : sysconfig register to manage phy parameter at driver level
+- resets               : list of phandle and reset specifier pairs. There should be two entries, one
+                         for the whole phy and one for the port
+- reset-names          : list of reset signal names. Should be "global" and "port"
+See: Documentation/devicetree/bindings/reset/st,sti-powerdown.txt
+See: Documentation/devicetree/bindings/reset/reset.txt
+
+Example:
+
+usb2_picophy0: usbpicophy@f8 {
+       compatible      = "st,stih407-usb2-phy";
+       reg             = <0xf8 0x04>,  /* syscfg 5062 */
+                         <0xf4 0x04>;  /* syscfg 5061 */
+       reg-names       = "param", "ctrl";
+       #phy-cells      = <0>;
+       st,syscfg       = <&syscfg_core>;
+       resets          = <&softreset STIH407_PICOPHY_SOFTRESET>,
+                         <&picophyreset STIH407_PICOPHY0_RESET>;
+       reset-names     = "global", "port";
+};