ec/google/wilco/acpi: Fix S3/S4 support

- Only run _REG on attach
- Reinitialize on WAK to support S3 / Hibernate

Adjustments taken from EC ACPI on Dell 5400/7410 Windows devices.

TEST=build/boot google/drallion, verify S3 sleep works properly as
well as S0ix.

Change-Id: I162d02c7d3c81f1106ddc65a3804f7112dda66b2
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/87488
Reviewed-by: Caveh Jalali <caveh@chromium.org>
Reviewed-by: Boris Mittelberg <bmbm@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

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

@@ -29,6 +29,10 @@ Device (EC0)
 	OperationRegion (ERAM, EmbeddedControl, 0, 0xff)
 	Method (_REG, 2)
 	{
+		If (Arg1 != 1) {
+			Return ()
+		}
+
 		/* Indicate region is registered */
 		EREG = Arg1
 

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

@@ -4,12 +4,30 @@
 Method (PTS, 1, Serialized)
 {
 	Printf ("EC _PTS")
-	W (FPTS, Arg0)
+	If (EREG){
+		W (FPTS, Arg0)
+	}
 }
 
 /* Call from \_SB._WAK() */
 Method (WAK, 1, Serialized)
 {
 	Printf ("EC _WAK")
-	W (FWAK, Arg0)
+	If (EREG){
+		W (FWAK, Arg0)
+
+		/* Indicate to EC that OS is ready for queries */
+		W (ERDY, 1)
+
+		/* Indicate that the OS supports S0ix */
+		W (CSOS, 1)
+
+		/* Tell EC to stop emulating PS/2 mouse */
+		W (PS2M, 0)
+
+		/* Enable DPTF support if enabled in devicetree */
+		If (\DPTE == 1) {
+			W (DWST, 1)
+		}
+	}
 }