HID: Add an input configured notification callback

A hid device may create several input devices, and a driver may need
to prepare or finalize the configuration per input device. Currently,
there is no sane way for a driver to know when a device has been
configured. This patch adds a callback providing that information.

Reviewed-and-tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Tested-by: Ping Cheng <pingc@wacom.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>

drivers/hid/hid-input.c

@@ -1154,6 +1154,7 @@ static void report_features(struct hid_device *hid)
 
 int hidinput_connect(struct hid_device *hid, unsigned int force)
 {
+	struct hid_driver *drv = hid->driver;
 	struct hid_report *report;
 	struct hid_input *hidinput = NULL;
 	struct input_dev *input_dev;
@@ -1228,15 +1229,21 @@ int hidinput_connect(struct hid_device *hid, unsigned int force)
 				 * UGCI) cram a lot of unrelated inputs into the
 				 * same interface. */
 				hidinput->report = report;
+				if (drv->input_configured)
+					drv->input_configured(hid, hidinput);
 				if (input_register_device(hidinput->input))
 					goto out_cleanup;
 				hidinput = NULL;
 			}
 		}
 	}
 
-	if (hidinput && input_register_device(hidinput->input))
-		goto out_cleanup;
+	if (hidinput) {
+		if (drv->input_configured)
+			drv->input_configured(hid, hidinput);
+		if (input_register_device(hidinput->input))
+			goto out_cleanup;
+	}
 
 	return 0;
 

include/linux/hid.h

@@ -626,6 +626,7 @@ struct hid_usage_id {
  * @report_fixup: called before report descriptor parsing (NULL means nop)
  * @input_mapping: invoked on input registering before mapping an usage
  * @input_mapped: invoked on input registering after mapping an usage
+ * @input_configured: invoked just before the device is registered
  * @feature_mapping: invoked on feature registering
  * @suspend: invoked on suspend (NULL means nop)
  * @resume: invoked on resume if device was not reset (NULL means nop)
@@ -670,6 +671,8 @@ struct hid_driver {
 	int (*input_mapped)(struct hid_device *hdev,
 			struct hid_input *hidinput, struct hid_field *field,
 			struct hid_usage *usage, unsigned long **bit, int *max);
+	void (*input_configured)(struct hid_device *hdev,
+				 struct hid_input *hidinput);
 	void (*feature_mapping)(struct hid_device *hdev,
 			struct hid_field *field,
 			struct hid_usage *usage);