ec/google/wilco: Add ACPI device for event interface

Add a separate ACPI device for the Wilco EC event interface so that the
OS drivers can bind to it separately.  Since the event handling is all
done with ACPI and not mailbox calls this will be implemented as a
standard acpi_driver in the kernel.

BUG=b:119046283
TEST=veriy device exists in DSDT

Change-Id: I5259a926fb6d5faea835bcdefa12f0184c5adf4a
Signed-off-by: Duncan Laurie <dlaurie@google.com>
Reviewed-on: https://review.coreboot.org/c/31204
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

src/ec/google/wilco/acpi/ec_dev.asl

@@ -62,3 +62,31 @@ Device (WLCO)
 		EndDependentFn ()
 	})
 }
+
+Device (WEVT)
+{
+	Name (_HID, "GOOG000D")
+	Name (_UID, 1)
+	Name (_DDN, "Wilco EC Event Interface")
+
+	Method (_STA)
+	{
+		Return (0xB)
+	}
+
+	/* Get Event Buffer */
+	Method (QSET, 0, Serialized)
+	{
+		/* Get count of event bytes */
+		Local0 = R (QSEC)
+		Name (QBUF, Buffer (Local0) {})
+
+		/* Fill QS event buffer with Local0 bytes */
+		For (Local1 = 0, Local1 < Local0, Local1++) {
+			QBUF[Local1] = R (QSEB)
+		}
+
+		Printf ("QS = %o", QBUF)
+		Return (QBUF)
+	}
+}

src/ec/google/wilco/acpi/event.asl

@@ -79,7 +79,7 @@ Method (ECQ2, 1, Serialized)
 
 	If (EBIT (E2QS, Arg0)) {
 		Printf ("QS EVENT")
-		Notify (^WLCO, 0x90)
+		Notify (^WEVT, 0x90)
 	}
 }
 
@@ -125,19 +125,3 @@ Method (_Q66, 0, Serialized)
 		ECQ4 (Local0)
 	}
 }
-
-/* Get Event Buffer */
-Method (QSET, 0, Serialized)
-{
-	/* Get count of event bytes */
-	Local0 = R (QSEC)
-	Name (QBUF, Buffer (Local0) {})
-
-	/* Fill QS event buffer with Local0 bytes */
-	For (Local1 = 0, Local1 < Local0, Local1++) {
-		QBUF[Local1] = R (QSEB)
-	}
-
-	Printf ("QS = %o", QBUF)
-	Return (QBUF)
-}