sunxi: Implement poweroff support for axp152 pmic

Adds poweroff support for axp152 pmic.

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

drivers/power/Kconfig

@@ -20,6 +20,7 @@ config SUNXI_NO_PMIC
 config AXP152_POWER
 	boolean "axp152 pmic support"
 	depends on MACH_SUN5I
+	select CMD_POWEROFF
 	---help---
 	Select this to enable support for the axp152 pmic found on most
 	A10s boards.

drivers/power/axp152.c

@@ -5,6 +5,7 @@
  * SPDX-License-Identifier:	GPL-2.0+
  */
 #include <common.h>
+#include <command.h>
 #include <asm/arch/pmic_bus.h>
 #include <axp_pmic.h>
 
@@ -78,3 +79,14 @@ int axp_init(void)
 
 	return 0;
 }
+
+int do_poweroff(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	pmic_bus_write(AXP152_SHUTDOWN, AXP152_POWEROFF);
+
+	/* infinite loop during shutdown */
+	while (1) {}
+
+	/* not reached */
+	return 0;
+}