Provide control over the source of the timestamp

This allows selecting between getting the timestamp from the camera or
from the system running the IOC.

The system timestamp is obtained from the aravis buffer which was saved on
the reception of the first packet of the image, this is more precise than
timestamping after receiving the full frame.

aravisApp/Db/aravisCamera.template

@@ -205,3 +205,24 @@ record(mbbo, "$(P)$(R)ARShiftBits") {
   field(PINI, "1")
   info(autosaveFields, "DESC ZRSV ONSV VAL")
 }
+
+record(mbbo, "$(P)$(R)TimeStampMode") {
+  field(DTYP, "asynInt32")
+  field(OUT,  "@asyn($(PORT),$(ADDR=0),$(TIMEOUT=1))ARAVIS_TIME_STAMP_MODE")
+  field(ZRST, "Camera")
+  field(ZRVL, "0")
+  field(ONST, "System")
+  field(ONVL, "1")
+  field(PINI, "1")
+  info(autosaveFields, "VAL")
+}
+
+record(mbbi, "$(P)$(R)TimeStampMode_RBV") {
+  field(DTYP, "asynInt32")
+  field(INP,  "@asyn($(PORT),$(ADDR=0),$(TIMEOUT=1))ARAVIS_TIME_STAMP_MODE")
+  field(ZRST, "Camera")
+  field(ZRVL, "0")
+  field(ONST, "System")
+  field(ONVL, "1")
+  field(SCAN, "I/O Intr")
+}