sunxi: Implement poweroff support for axp818 pmic

Adds poweroff support for axp818 pmic.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Reviewed-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NHans de Goede <hdegoede@redhat.com>

drivers/power/Kconfig

@@ -44,6 +44,7 @@ config AXP221_POWER
 config AXP818_POWER
 	boolean "axp818 pmic support"
 	depends on MACH_SUN8I_A83T
+	select CMD_POWEROFF
 	---help---
 	Say y here to enable support for the axp818 pmic found on
 	A83T dev board.

drivers/power/axp818.c

@@ -255,3 +255,14 @@ int axp_init(void)
 
 	return 0;
 }
+
+int do_poweroff(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	pmic_bus_write(AXP818_SHUTDOWN, AXP818_SHUTDOWN_POWEROFF);
+
+	/* infinite loop during shutdown */
+	while (1) {}
+
+	/* not reached */
+	return 0;
+}

include/axp818.h

@@ -55,6 +55,9 @@
 #define AXP818_ALDO2_CTRL	0x29
 #define AXP818_ALDO3_CTRL	0x2a
 
+#define AXP818_SHUTDOWN		0x32
+#define AXP818_SHUTDOWN_POWEROFF	(1 << 7)
+
 /* For axp_gpio.c */
 #define AXP_POWER_STATUS		0x00
 #define AXP_POWER_STATUS_VBUS_PRESENT		(1 << 5)