mb/lenovo: Support dual graphics for xx20/xx30 ThinkPads

Add CMOS option that allows to use both integrated and discrete GPU.

Tested on ThinkPad W530.

Change-Id: I8842fef0fa1235eb91abf6b7e655ed4d8598adc7
Signed-off-by: Evgeny Zinoviev <me@ch1p.com>
Reviewed-on: https://review.coreboot.org/28393
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/ec/lenovo/pmh7/pmh7.c

@@ -19,6 +19,7 @@
 #include <device/pnp.h>
 #include <stdlib.h>
 #include <pc80/mc146818rtc.h>
+#include <delay.h>
 
 #include "pmh7.h"
 #include "chip.h"
@@ -64,6 +65,26 @@ void pmh7_ultrabay_power_enable(int onoff)
 		pmh7_register_set_bit(0x62, 0);
 }
 
+void pmh7_dgpu_power_enable(int onoff)
+{
+	if (onoff) {
+		pmh7_register_clear_bit(0x50, 7); // DGPU_RST
+		pmh7_register_set_bit(0x50, 3); // DGPU_PWR
+		mdelay(10);
+		pmh7_register_set_bit(0x50, 7); // DGPU_RST
+		mdelay(50);
+	} else {
+		pmh7_register_clear_bit(0x50, 7); // DGPU_RST
+		udelay(100);
+		pmh7_register_clear_bit(0x50, 3); // DGPU_PWR
+	}
+}
+
+bool pmh7_dgpu_power_state(void)
+{
+	return (pmh7_register_read(0x50) & 0x08) == 8;
+}
+
 void pmh7_register_set_bit(int reg, int bit)
 {
 	char val;

src/ec/lenovo/pmh7/pmh7.h

@@ -35,5 +35,7 @@ void pmh7_dock_event_enable(int onoff);
 void pmh7_touchpad_enable(int onoff);
 void pmh7_ultrabay_power_enable(int onoff);
 void pmh7_trackpoint_enable(int onoff);
+void pmh7_dgpu_power_enable(int onoff);
+bool pmh7_dgpu_power_state(void);
 
 #endif /* EC_LENOVO_PMH7_H */