wkup_m3_ipc: Add support for toggling VTT regulator
[rpmsg/hwspinlock.git] / Documentation / devicetree / bindings / soc / ti / wkup_m3_ipc.txt
index 401550487ed6f69f036a810dd6e01edcef745b87..4cdbb60fd0d0bace26aed3155b7dcf942545275b 100644 (file)
@@ -55,3 +55,37 @@ Example:
                        ...
                };
        };
+
+Support for VTT Toggle
+==================================
+In order to enable the support for VTT toggle during Suspend/Resume
+sequence needed by some boards (like AM335x EVM-SK & AM437x GP EVM),
+the below DT properties are required. It is possible to toggle VTT
+using one of two methods depending on the SoC being used, either
+GPIO0 toggle (AM335x and AM437x), or any GPIO with DS_PAD_CONFIG
+bits in the control module (AM437x only).
+
+VTT Toggle using GPIO0
+----------------------------------
+Supported by: AM335x and AM437x
+Used on: AM335x EVM-SK
+
+Optional properties:
+- ti,needs-vtt-toggle: Indicates that the boards requires VTT toggling
+                       during suspend/resume.
+- ti,vtt-gpio-pin:     Specifies the GPIO0 pin used for VTT toggle.
+
+Important Note:
+- Here it is assumed that VTT Toggle will be done using a pin on GPIO-0 Instance.
+  It will not work on any other GPIO using the above properties, regardless of
+  which part is being used.
+
+Example:
+       wkup_m3_ipc: wkup_m3_ipc@1324 {
+               compatible = "ti,am3352-wkup-m3-ipc";
+               ...
+               ...
+               ti,needs-vtt-toggle;
+               ti,vtt-gpio-pin = <7>;
+               ...
+       };