usb: musb: core: Convert the musb_platform_reset to have a return value.

Currently musb_platform_reset() is only used by dsps.
In case of BABBLE interrupt for other platforms the  musb_platform_reset()
is a NOP. In such situations no need to re-initialize the endpoints.
Also in the latest silicon revision of AM335x, we do have a babble recovery
mechanism without resetting the IP block. In preperation to add that support
its better to have a rest_done return for  musb_platform_reset().

Signed-off-by: George Cherian <george.cherian@ti.com>
Tested-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/musb/musb_core.c

@@ -1753,9 +1753,11 @@ static void musb_irq_work(struct work_struct *data)
 static void musb_recover_work(struct work_struct *data)
 {
 	struct musb *musb = container_of(data, struct musb, recover_work.work);
-	int status;
+	int status, ret;
 
-	musb_platform_reset(musb);
+	ret  = musb_platform_reset(musb);
+	if (ret)
+		return;
 
 	usb_phy_vbus_off(musb->xceiv);
 	usleep_range(100, 200);
@@ -1764,8 +1766,8 @@ static void musb_recover_work(struct work_struct *data)
 	usleep_range(100, 200);
 
 	/*
-	 * When a babble condition occurs, the musb controller removes the
-	 * session bit and the endpoint config is lost.
+	 * When a babble condition occurs, the musb controller
+	 * removes the session bit and the endpoint config is lost.
 	 */
 	if (musb->dyn_fifo)
 		status = ep_config_from_table(musb);

drivers/usb/musb/musb_core.h

@@ -192,7 +192,7 @@ struct musb_platform_ops {
 
 	int	(*set_mode)(struct musb *musb, u8 mode);
 	void	(*try_idle)(struct musb *musb, unsigned long timeout);
-	void	(*reset)(struct musb *musb);
+	int	(*reset)(struct musb *musb);
 
 	int	(*vbus_status)(struct musb *musb);
 	void	(*set_vbus)(struct musb *musb, int on);
@@ -555,10 +555,12 @@ static inline void musb_platform_try_idle(struct musb *musb,
 		musb->ops->try_idle(musb, timeout);
 }
 
-static inline void musb_platform_reset(struct musb *musb)
+static inline int  musb_platform_reset(struct musb *musb)
 {
-	if (musb->ops->reset)
-		musb->ops->reset(musb);
+	if (!musb->ops->reset)
+		return -EINVAL;
+
+	return musb->ops->reset(musb);
 }
 
 static inline int musb_platform_get_vbus_status(struct musb *musb)

drivers/usb/musb/musb_dsps.c

@@ -544,7 +544,7 @@ static int dsps_musb_set_mode(struct musb *musb, u8 mode)
 	return 0;
 }
 
-static void dsps_musb_reset(struct musb *musb)
+static int dsps_musb_reset(struct musb *musb)
 {
 	struct device *dev = musb->controller;
 	struct dsps_glue *glue = dev_get_drvdata(dev->parent);
@@ -556,6 +556,7 @@ static void dsps_musb_reset(struct musb *musb)
 	usleep_range(100, 200);
 	usb_phy_init(musb->xceiv);
 
+	return 0;
 }
 
 static struct musb_platform_ops dsps_ops = {