sunxi: axp221: Allow specifying dcdc2 voltage via Kconfig

Allow specifying the axp221 dcdc2 voltage via Kconfig, this is necessary
because on some boards the 1.2V default does not work reliable.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>

board/sunxi/board.c

@@ -437,7 +437,7 @@ void sunxi_board_init(void)
 #ifdef CONFIG_AXP221_POWER
 	power_failed = axp221_init();
 	power_failed |= axp221_set_dcdc1(CONFIG_AXP221_DCDC1_VOLT);
-	power_failed |= axp221_set_dcdc2(1200); /* A31:VDD-GPU, A23:VDD-SYS */
+	power_failed |= axp221_set_dcdc2(CONFIG_AXP221_DCDC2_VOLT);
 	power_failed |= axp221_set_dcdc3(1200); /* VDD-CPU */
 #ifdef CONFIG_MACH_SUN6I
 	power_failed |= axp221_set_dcdc4(1200); /* A31:VDD-SYS */

drivers/power/Kconfig

@@ -22,6 +22,15 @@ config AXP221_DCDC1_VOLT
 	things like GPIO-s, sdcard interfaces, etc. On most boards this is
 	undervolted to 3.0V to safe battery.
 
+config AXP221_DCDC2_VOLT
+	int "axp221 dcdc2 voltage"
+	depends on AXP221_POWER
+	default 1200
+	---help---
+	Set the voltage (mV) to program the axp221 dcdc2 at, set to 0 to
+	disable dcdc2. On A31 boards this is typically used for VDD-GPU,
+	on A23/A33 for VDD-SYS, this should normally be set to 1.2V.
+
 config AXP221_DLDO1_VOLT
 	int "axp221 dldo1 voltage"
 	depends on AXP221_POWER