sunxi: axp221: Add VBUS detection support

Some of the AXP PMICs support VBUS detection, i.e. checking whether
VBUS power input is available and usable (supplied by an external
source). A few boards use this instead of a separate GPIO to detect
VBUS on USB OTG.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/power/axp221.c

@@ -385,6 +385,22 @@ int axp221_get_sid(unsigned int *sid)
 	return 0;
 }
 
+int axp_get_vbus(void)
+{
+	int ret;
+	u8 val;
+
+	ret = axp221_init();
+	if (ret)
+		return ret;
+
+	ret = pmic_bus_read(AXP221_POWER_STATUS, &val);
+	if (ret)
+		return ret;
+
+	return (val & AXP221_POWER_STATUS_VBUS_USABLE) ? 1 : 0;
+}
+
 static int axp_drivebus_setup(void)
 {
 	int ret;

include/axp221.h

@@ -14,6 +14,9 @@
 #define AXP223_RUNTIME_ADDR 0x2d
 
 /* Page 0 addresses */
+#define AXP221_POWER_STATUS	0x00
+#define AXP221_POWER_STATUS_VBUS_AVAIL	(1 << 5)
+#define AXP221_POWER_STATUS_VBUS_USABLE	(1 << 4)
 #define AXP221_CHIP_ID		0x03
 #define AXP221_OUTPUT_CTRL1	0x10
 #define AXP221_OUTPUT_CTRL1_DCDC0_EN	(1 << 0)
@@ -59,6 +62,9 @@
 /* Page 1 addresses */
 #define AXP221_SID		0x20
 
+/* We support vbus detection */
+#define AXP_VBUS_DETECT
+
 /* We support drivebus control */
 #define AXP_DRIVEBUS
 
@@ -77,5 +83,6 @@ int axp221_set_aldo3(unsigned int mvolt);
 int axp221_set_eldo(int eldo_num, unsigned int mvolt);
 int axp221_init(void);
 int axp221_get_sid(unsigned int *sid);
+int axp_get_vbus(void);
 int axp_drivebus_enable(void);
 int axp_drivebus_disable(void);