USB: expand autosuspend/autoresume API

This patch (as814) adds usb_autopm_set_interface() to the autosuspend
API.  It also provides convenient wrapper routines,
usb_autopm_enable() and usb_autopm_disable(), for drivers that want
to specify directly whether autosuspend should be allowed.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/driver.c

@@ -1322,6 +1322,28 @@ int usb_autopm_get_interface(struct usb_interface *intf)
 }
 EXPORT_SYMBOL_GPL(usb_autopm_get_interface);
 
+/**
+ * usb_autopm_set_interface - set a USB interface's autosuspend state
+ * @intf: the usb_interface whose state should be set
+ *
+ * This routine sets the autosuspend state of @intf's device according
+ * to @intf's usage counter, which the caller must have set previously.
+ * If the counter is <= 0, the device is autosuspended (if it isn't
+ * already suspended and if nothing else prevents the autosuspend).  If
+ * the counter is > 0, the device is autoresumed (if it isn't already
+ * awake).
+ */
+int usb_autopm_set_interface(struct usb_interface *intf)
+{
+	int	status;
+
+	status = usb_autopm_do_interface(intf, 0);
+	// dev_dbg(&intf->dev, "%s: status %d cnt %d\n",
+	//		__FUNCTION__, status, intf->pm_usage_cnt);
+	return status;
+}
+EXPORT_SYMBOL_GPL(usb_autopm_set_interface);
+
 #endif /* CONFIG_USB_SUSPEND */
 
 static int usb_suspend(struct device *dev, pm_message_t message)

include/linux/usb.h

@@ -415,14 +415,37 @@ extern struct usb_device *usb_find_device(u16 vendor_id, u16 product_id);
 
 /* USB autosuspend and autoresume */
 #ifdef CONFIG_USB_SUSPEND
+extern int usb_autopm_set_interface(struct usb_interface *intf);
 extern int usb_autopm_get_interface(struct usb_interface *intf);
 extern void usb_autopm_put_interface(struct usb_interface *intf);
 
-#else
+static inline void usb_autopm_enable(struct usb_interface *intf)
-#define usb_autopm_get_interface(intf)		0
+{
-#define usb_autopm_put_interface(intf)		do {} while (0)
+	intf->pm_usage_cnt = 0;
-#endif
+	usb_autopm_set_interface(intf);
+}
 
+static inline void usb_autopm_disable(struct usb_interface *intf)
+{
+	intf->pm_usage_cnt = 1;
+	usb_autopm_set_interface(intf);
+}
+
+#else
+
+static inline int usb_autopm_set_interface(struct usb_interface *intf)
+{ return 0; }
+
+static inline int usb_autopm_get_interface(struct usb_interface *intf)
+{ return 0; }
+
+static inline void usb_autopm_put_interface(struct usb_interface *intf)
+{ }
+static inline void usb_autopm_enable(struct usb_interface *intf)
+{ }
+static inline void usb_autopm_disable(struct usb_interface *intf)
+{ }
+#endif
 
 /*-------------------------------------------------------------------------*/