usb: dwc2: Update port suspend/resume function definitions.

Earlier "dwc2_port_suspend()" and "dwc2_port_resume()" functions
were implemented without proper description and host or device mode
difference.

- Added "dwc2_port_suspend" and "dwc2_port_resume" functions to
  "core.h" header file.

- Updated function description in documentation.
Acked-by: Minas Harutyunyan <Minas.Harutyunyan@synopsys.com>
Signed-off-by: Artur Petrosyan <Arthur.Petrosyan@synopsys.com>
Link: https://lore.kernel.org/r/20210408094502.61D18A0232@mailhost.synopsys.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/dwc2/core.h

@@ -1470,6 +1470,8 @@ void dwc2_hcd_connect(struct dwc2_hsotg *hsotg);
 void dwc2_hcd_disconnect(struct dwc2_hsotg *hsotg, bool force);
 void dwc2_hcd_start(struct dwc2_hsotg *hsotg);
 int dwc2_core_init(struct dwc2_hsotg *hsotg, bool initial_setup);
+void dwc2_port_suspend(struct dwc2_hsotg *hsotg, u16 windex);
+void dwc2_port_resume(struct dwc2_hsotg *hsotg);
 int dwc2_backup_host_registers(struct dwc2_hsotg *hsotg);
 int dwc2_restore_host_registers(struct dwc2_hsotg *hsotg);
 int dwc2_host_enter_hibernation(struct dwc2_hsotg *hsotg);
@@ -1493,6 +1495,8 @@ static inline void dwc2_hcd_start(struct dwc2_hsotg *hsotg) {}
 static inline void dwc2_hcd_remove(struct dwc2_hsotg *hsotg) {}
 static inline int dwc2_core_init(struct dwc2_hsotg *hsotg, bool initial_setup)
 { return 0; }
+static inline void dwc2_port_suspend(struct dwc2_hsotg *hsotg, u16 windex) {}
+static inline void dwc2_port_resume(struct dwc2_hsotg *hsotg) {}
 static inline int dwc2_hcd_init(struct dwc2_hsotg *hsotg)
 { return 0; }
 static inline int dwc2_backup_host_registers(struct dwc2_hsotg *hsotg)

drivers/usb/dwc2/hcd.c

@@ -56,8 +56,6 @@
 #include "core.h"
 #include "hcd.h"
 
-static void dwc2_port_resume(struct dwc2_hsotg *hsotg);
-
 /*
  * =========================================================================
  *  Host Core Layer Functions
@@ -3277,8 +3275,16 @@ static int dwc2_host_is_b_hnp_enabled(struct dwc2_hsotg *hsotg)
 	return hcd->self.b_hnp_enable;
 }
 
-/* Must NOT be called with interrupt disabled or spinlock held */
-static void dwc2_port_suspend(struct dwc2_hsotg *hsotg, u16 windex)
+/**
+ * dwc2_port_suspend() - Put controller in suspend mode for host.
+ *
+ * @hsotg: Programming view of the DWC_otg controller
+ * @windex: The control request wIndex field
+ *
+ * This function is for entering Host mode suspend.
+ * Must NOT be called with interrupt disabled or spinlock held.
+ */
+void dwc2_port_suspend(struct dwc2_hsotg *hsotg, u16 windex)
 {
 	unsigned long flags;
 	u32 hprt0;
@@ -3328,8 +3334,15 @@ static void dwc2_port_suspend(struct dwc2_hsotg *hsotg, u16 windex)
 	}
 }
 
-/* Must NOT be called with interrupt disabled or spinlock held */
-static void dwc2_port_resume(struct dwc2_hsotg *hsotg)
+/**
+ * dwc2_port_resume() - Exit controller from suspend mode for host.
+ *
+ * @hsotg: Programming view of the DWC_otg controller
+ *
+ * This function is for exiting Host mode suspend.
+ * Must NOT be called with interrupt disabled or spinlock held.
+ */
+void dwc2_port_resume(struct dwc2_hsotg *hsotg)
 {
 	unsigned long flags;
 	u32 hprt0;