ec/google: Use feature flag layout that matches the EC host command

The EC side of the feature bits in ACPI EC space isn't stable yet, and
we're now going for matching them up with the EC host command of the
same purpose.

Change-Id: I9c1f0e5390e840ea0c32315a3da8eea6f3e12f54
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: https://review.coreboot.org/21193
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/ec/google/chromeec/acpi/ec.asl

@@ -47,15 +47,49 @@ Device (EC0)
 		RAMV, 8,	// EC RAM Version
 		TSTB, 8,	// Test Byte
 		TSTC, 8,	// Complement of Test Byte
-		KBLV, 8,	// Keyboard Backlight
+		KBLV, 8,	// Keyboard Backlight value
 		FAND, 8,	// Set Fan Duty Cycle
 		PATI, 8,	// Programmable Auxiliary Trip Sensor ID
 		PATT, 8,	// Programmable Auxiliary Trip Threshold
 		PATC, 8,	// Programmable Auxiliary Trip Commit
 		CHGL, 8,	// Charger Current Limit
 		TBMD, 1,	// Tablet mode
+		// DFUD must be 0 for the other 31 values to be valid
 		Offset (0x0a),
-		KBLE, 1,	// Keyboard Backlight exists
+		DFUD, 1,	// Device Features Undefined
+		FLSH, 1,	// Flash commands present
+		PFAN, 1,	// PWM Fan control present
+		KBLE, 1,	// Keyboard Backlight present
+		LTBR, 1,	// Lightbar present
+		LEDC, 1,	// LED control
+		MTNS, 1,	// Motion sensors present
+		KEYB, 1,	// EC is keyboard controller
+		PSTR, 1,	// Persistent storage
+		P80P, 1,	// EC serves I/O Port 80h
+		THRM, 1,	// EC supports thermal management
+		SBKL, 1,	// Screen backlight switch present
+		WIFI, 1,	// WIFI switch present
+		HOST, 1,	// EC monitors host events (eg SCI, SMI)
+		GPIO, 1,	// EC provides GPIO commands
+		I2CB, 1,	// EC provides I2C controller access
+		CHRG, 1,	// EC provides commands for charger control
+		BATT, 1,	// Simply Battery support
+		SBAT, 1,	// Smart Battery support
+		HANG, 1,	// EC can detect host hang
+		PMUI, 1,	// Power Information
+		DSEC, 1,	// another EC exists downstream
+		UPDC, 1,	// supports USB Power Delivery
+		UMUX, 1,	// supports USB Mux
+		MSFF, 1,	// Motion Sense has FIFO
+		TVST, 1,	// supports temporary secure vstore
+		TCMV, 1,	// USB Type C Muxing is virtual (host assisted)
+		RTCD, 1,	// EC provides an RTC device
+		FPRD, 1,	// EC provides a fingerprint reader device
+		TPAD, 1,	// EC provides a touchpad device
+		RWSG, 1,	// EC has RWSIG task enabled
+		DEVE, 1,	// EC supports device events
+		// make sure we're within our space envelope
+		Offset (0x0e),
 	}
 
 #if IS_ENABLED(CONFIG_EC_GOOGLE_CHROMEEC_ACPI_MEMMAP)

src/ec/google/chromeec/acpi/keyboard_backlight.asl

@@ -33,8 +33,18 @@ Scope (\_SB)
 		 */
 		Method (_STA, 0, NotSerialized)
 		{
-			Multiply (0xf, \_SB.PCI0.LPCB.EC0.KBLE, Local0)
+			/* If query is unsupported, but this code is compiled
-			Return (Local0)
+			 * in, assume the backlight exists physically.
+			 */
+			If (LEqual (1, \_SB.PCI0.LPCB.EC0.DFUD)) {
+				Return (0xf)
+			}
+			/* If EC reports that backlight exists, trust it */
+			If (LEqual (1, \_SB.PCI0.LPCB.EC0.KBLE)) {
+				Return (0xf)
+			}
+			/* Otherwise: no device -> disable */
+			Return (0)
 		}
 
 		/* Read current backlight value */