diff --git a/sys/dev/ichiic/ig4_iic.c b/sys/dev/ichiic/ig4_iic.c
--- a/sys/dev/ichiic/ig4_iic.c
+++ b/sys/dev/ichiic/ig4_iic.c
@@ -537,7 +537,6 @@
 	int unit;
 	bool rpstart;
 	bool stop;
-	bool allocated;
 
 	/*
 	 * The hardware interface imposes limits on allowed I2C messages.
@@ -599,9 +598,7 @@
 	}
 
 	/* Check if device is already allocated with iicbus_request_bus() */
-	allocated = sx_xlocked(&sc->call_lock) != 0;
-	if (!allocated)
-		sx_xlock(&sc->call_lock);
+	sx_xlock(&sc->bus_lock);
 
 	/* Debugging - dump registers. */
 	if (ig4_dump) {
@@ -679,8 +676,7 @@
 		device_printf(dev, "Warning: NACK for slave address 0x%x\n",
 		    msgs[i].slave >> 1);
 
-	if (!allocated)
-		sx_unlock(&sc->call_lock);
+	sx_unlock(&sc->bus_lock);
 	return (error);
 }
 
@@ -688,11 +684,8 @@
 ig4iic_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
 {
 	ig4iic_softc_t *sc = device_get_softc(dev);
-	bool allocated;
 
-	allocated = sx_xlocked(&sc->call_lock) != 0;
-	if (!allocated)
-		sx_xlock(&sc->call_lock);
+	sx_xlock(&sc->bus_lock);
 
 	/* TODO handle speed configuration? */
 	if (oldaddr != NULL)
@@ -701,8 +694,7 @@
 	if (addr == IIC_UNKNOWN)
 		sc->slave_valid = false;
 
-	if (!allocated)
-		sx_unlock(&sc->call_lock);
+	sx_unlock(&sc->bus_lock);
 	return (0);
 }
 
@@ -1035,8 +1027,9 @@
 {
 	int error;
 
-	mtx_init(&sc->io_lock, "IG4 I/O lock", NULL, MTX_SPIN);
 	sx_init(&sc->call_lock, "IG4 call lock");
+	sx_init(&sc->bus_lock, "IG4 bus lock");
+	mtx_init(&sc->io_lock, "IG4 I/O lock", NULL, MTX_SPIN);
 
 	ig4iic_get_config(sc);
 
@@ -1095,15 +1088,18 @@
 		bus_teardown_intr(sc->dev, sc->intr_res, sc->intr_handle);
 
 	sx_xlock(&sc->call_lock);
+	sx_xlock(&sc->bus_lock);
 
 	sc->iicbus = NULL;
 	sc->intr_handle = NULL;
 	reg_write(sc, IG4_REG_INTR_MASK, 0);
 	set_controller(sc, 0);
 
+	sx_xunlock(&sc->bus_lock);
 	sx_xunlock(&sc->call_lock);
 
 	mtx_destroy(&sc->io_lock);
+	sx_destroy(&sc->bus_lock);
 	sx_destroy(&sc->call_lock);
 
 	return (0);
@@ -1117,7 +1113,7 @@
 	/* suspend all children */
 	error = bus_generic_suspend(sc->dev);
 
-	sx_xlock(&sc->call_lock);
+	sx_xlock(&sc->bus_lock);
 	set_controller(sc, 0);
 	if (IG4_HAS_ADDREGS(sc->version)) {
 		/*
@@ -1131,7 +1127,7 @@
 		 */
 		reg_write(sc, IG4_REG_RESETS_SKL, IG4_RESETS_ASSERT_SKL);
 	}
-	sx_xunlock(&sc->call_lock);
+	sx_xunlock(&sc->bus_lock);
 
 	return (error);
 }
@@ -1140,10 +1136,10 @@
 {
 	int error;
 
-	sx_xlock(&sc->call_lock);
+	sx_xlock(&sc->bus_lock);
 	if (ig4iic_set_config(sc, IG4_HAS_ADDREGS(sc->version)))
 		device_printf(sc->dev, "controller error during resume\n");
-	sx_xunlock(&sc->call_lock);
+	sx_xunlock(&sc->bus_lock);
 
 	error = bus_generic_resume(sc->dev);
 
diff --git a/sys/dev/ichiic/ig4_var.h b/sys/dev/ichiic/ig4_var.h
--- a/sys/dev/ichiic/ig4_var.h
+++ b/sys/dev/ichiic/ig4_var.h
@@ -102,12 +102,16 @@
 	 * with the controller acquire an exclusive lock on call_lock
 	 * to prevent interleaving of calls to the interface.
 	 *
+	 * Bus_lock provides exclusive access to the bus as call_lock
+	 * is used by an API which is only advisory.
+	 *
 	 * io_lock is used as condition variable to synchronize active process
 	 * with the interrupt handler. It should not be used for tasks other
 	 * than waiting for interrupt and passing parameters to and from
 	 * it's handler.
 	 */
 	struct sx	call_lock;
+	struct sx	bus_lock;
 	struct mtx	io_lock;
 };