Index: head/sys/arm/allwinner/axp209.c
===================================================================
--- head/sys/arm/allwinner/axp209.c
+++ head/sys/arm/allwinner/axp209.c
@@ -41,6 +41,7 @@
 #include <sys/reboot.h>
 #include <sys/resource.h>
 #include <sys/rman.h>
+#include <sys/sysctl.h>
 
 #include <dev/iicbus/iicbus.h>
 #include <dev/iicbus/iiconf.h>
@@ -62,11 +63,23 @@
 #define	AXP209_SHUTBAT		0x32
 #define	AXP209_SHUTBAT_SHUTDOWN	0x80
 
+/* Temperature monitor */
+#define	AXP209_TEMPMON		0x5e
+#define	AXP209_TEMPMON_H(a)	((a) << 4)
+#define	AXP209_TEMPMON_L(a)	((a) & 0xf)
+#define	AXP209_TEMPMON_MIN	1447	/* -144.7C */
+
+#define	AXP209_0C_TO_K		2732
+
 struct axp209_softc {
 	uint32_t		addr;
 	struct intr_config_hook enum_hook;
 };
 
+enum axp209_sensor {
+	AXP209_TEMP
+};
+
 static int
 axp209_read(device_t dev, uint8_t reg, uint8_t *data, uint8_t size)
 {
@@ -104,6 +117,28 @@
 	return (iicbus_transfer(dev, &msg, 1));
 }
 
+static int
+axp209_sysctl(SYSCTL_HANDLER_ARGS)
+{
+	device_t dev = arg1;
+	enum axp209_sensor sensor = arg2;
+	uint8_t data[2];
+	int val, error;
+
+	if (sensor != AXP209_TEMP)
+		return (ENOENT);
+
+	error = axp209_read(dev, AXP209_TEMPMON, data, 2);
+	if (error != 0)
+		return (error);
+
+	/* Temperature is between -144.7C and 264.8C, step +0.1C */
+	val = (AXP209_TEMPMON_H(data[0]) | AXP209_TEMPMON_L(data[1])) -
+	    AXP209_TEMPMON_MIN + AXP209_0C_TO_K;
+
+	return sysctl_handle_opaque(oidp, &val, sizeof(val), req);
+}
+
 static void
 axp209_shutdown(void *devp, int howto)
 {
@@ -163,6 +198,12 @@
 	EVENTHANDLER_REGISTER(shutdown_final, axp209_shutdown, dev,
 	    SHUTDOWN_PRI_LAST);
 
+	SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
+	    SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
+	    OID_AUTO, "temp",
+	    CTLTYPE_INT | CTLFLAG_RD,
+	    dev, AXP209_TEMP, axp209_sysctl, "IK", "Internal temperature");
+
 	return (0);
 }