ec/lenovo/h8/acpi: Fix ACPI error in _INI

Store the power on defaults in the _REG method after the ERAM region
is ready for use. It might not be ready when accessed from _INI.

Tested on Lenovo T430.

Change-Id: I70f22f8ac61dd850180fa159313bb0f8e4ab31d9
Signed-off-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-on: https://review.coreboot.org/27710
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

src/ec/lenovo/h8/acpi/ec.asl

@@ -75,6 +75,20 @@ Device(EC)
 				DKR3, 1		/* Dock register 3 */
 	}
 
+	/* Called on OperationRegion driver changes */
+	Method (_REG, 2, NotSerialized)
+	{
+		/* Wait for ERAM driver loaded */
+		if (LEqual(Arg1, One)) {
+			/* Fill HKEY defaults on first boot */
+			if (LEqual(^HKEY.INIT, Zero)) {
+				Store (BTEB, ^HKEY.WBDC)
+				Store (WWEB, ^HKEY.WWAN)
+				Store (One, ^HKEY.INIT)
+			}
+		}
+	}
+
 	Method (_CRS, 0, Serialized)
 	{
 		Name (ECMD, ResourceTemplate()

src/ec/lenovo/h8/acpi/thinkpad.asl

@@ -157,6 +157,9 @@ Device (HKEY)
 		Return (\_SB.PCI0.LPCB.EC.GSTS)
 	}
 
+	/* Set to one on first boot */
+	Name (INIT, 0)
+
 	/* Has thinkpad_acpi module loaded */
 	Name (HAST, 0)
 
@@ -304,15 +307,6 @@ Device (HKEY)
 		}
 	}
 
-	/*
-	 * Store initial state
-	 */
-	Method (_INI, 0, NotSerialized)
-	{
-		Store (\_SB.PCI0.LPCB.EC.BTEB, WBDC)
-		Store (\_SB.PCI0.LPCB.EC.WWEB, WWAN)
-	}
-
 	/*
 	 * Called from _WAK
 	 */