usb: phy: protect against NULL phy pointers

In order to decrease the amount of work done
by PHY users, allow NULL phy pointers to be
passed.

Signed-off-by: Felipe Balbi <balbi@ti.com>

include/linux/usb/phy.h

@@ -142,7 +142,7 @@ extern void usb_remove_phy(struct usb_phy *);
 /* helpers for direct access thru low-level io interface */
 static inline int usb_phy_io_read(struct usb_phy *x, u32 reg)
 {
-	if (x->io_ops && x->io_ops->read)
+	if (x && x->io_ops && x->io_ops->read)
 		return x->io_ops->read(x, reg);
 
 	return -EINVAL;
@@ -150,7 +150,7 @@ static inline int usb_phy_io_read(struct usb_phy *x, u32 reg)
 
 static inline int usb_phy_io_write(struct usb_phy *x, u32 val, u32 reg)
 {
-	if (x->io_ops && x->io_ops->write)
+	if (x && x->io_ops && x->io_ops->write)
 		return x->io_ops->write(x, val, reg);
 
 	return -EINVAL;
@@ -159,7 +159,7 @@ static inline int usb_phy_io_write(struct usb_phy *x, u32 val, u32 reg)
 static inline int
 usb_phy_init(struct usb_phy *x)
 {
-	if (x->init)
+	if (x && x->init)
 		return x->init(x);
 
 	return 0;
@@ -168,14 +168,14 @@ usb_phy_init(struct usb_phy *x)
 static inline void
 usb_phy_shutdown(struct usb_phy *x)
 {
-	if (x->shutdown)
+	if (x && x->shutdown)
 		x->shutdown(x);
 }
 
 static inline int
 usb_phy_vbus_on(struct usb_phy *x)
 {
-	if (!x->set_vbus)
+	if (!x || !x->set_vbus)
 		return 0;
 
 	return x->set_vbus(x, true);
@@ -184,7 +184,7 @@ usb_phy_vbus_on(struct usb_phy *x)
 static inline int
 usb_phy_vbus_off(struct usb_phy *x)
 {
-	if (!x->set_vbus)
+	if (!x || !x->set_vbus)
 		return 0;
 
 	return x->set_vbus(x, false);
@@ -258,7 +258,7 @@ usb_phy_set_power(struct usb_phy *x, unsigned mA)
 static inline int
 usb_phy_set_suspend(struct usb_phy *x, int suspend)
 {
-	if (x->set_suspend != NULL)
+	if (x && x->set_suspend != NULL)
 		return x->set_suspend(x, suspend);
 	else
 		return 0;
@@ -267,7 +267,7 @@ usb_phy_set_suspend(struct usb_phy *x, int suspend)
 static inline int
 usb_phy_notify_connect(struct usb_phy *x, enum usb_device_speed speed)
 {
-	if (x->notify_connect)
+	if (x && x->notify_connect)
 		return x->notify_connect(x, speed);
 	else
 		return 0;
@@ -276,7 +276,7 @@ usb_phy_notify_connect(struct usb_phy *x, enum usb_device_speed speed)
 static inline int
 usb_phy_notify_disconnect(struct usb_phy *x, enum usb_device_speed speed)
 {
-	if (x->notify_disconnect)
+	if (x && x->notify_disconnect)
 		return x->notify_disconnect(x, speed);
 	else
 		return 0;