HID: lenovo: Prepare support for adding other devices

Ensure all tpkbd specifics are within a postfixed function, the
main functions for the driver should just switch to the appropriate
function depending on product ID. Given this, we can add extra devices
by including extra postfixed functions.
Signed-off-by: Jamie Lentin <jm@lentin.co.uk>
Reviewed-by: Antonio Ospite <ao2@ao2.it>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-lenovo.c

 /*
- *  HID driver for Lenovo ThinkPad USB Keyboard with TrackPoint
+ *  HID driver for Lenovo:
+ *  - ThinkPad USB Keyboard with TrackPoint (tpkbd)
  *
  *  Copyright (c) 2012 Bernhard Seibold
  */
@@ -39,7 +40,7 @@ static int lenovo_input_mapping_tpkbd(struct hid_device *hdev,
 		struct hid_usage *usage, unsigned long **bit, int *max)
 {
 	if (usage->hid == (HID_UP_BUTTON | 0x0010)) {
-		/* mark the device as pointer */
+		/* This sub-device contains trackpoint, mark it */
 		hid_set_drvdata(hdev, (void *)1);
 		map_key_clear(KEY_MICMUTE);
 		return 1;
@@ -47,6 +48,19 @@ static int lenovo_input_mapping_tpkbd(struct hid_device *hdev,
 	return 0;
 }
 
+static int lenovo_input_mapping(struct hid_device *hdev,
+		struct hid_input *hi, struct hid_field *field,
+		struct hid_usage *usage, unsigned long **bit, int *max)
+{
+	switch (hdev->product) {
+	case USB_DEVICE_ID_LENOVO_TPKBD:
+		return lenovo_input_mapping_tpkbd(hdev, hi, field,
+							usage, bit, max);
+	default:
+		return 0;
+	}
+}
+
 #undef map_key_clear
 
 static int lenovo_features_set_tpkbd(struct hid_device *hdev)
@@ -337,6 +351,15 @@ static int lenovo_probe_tpkbd(struct hid_device *hdev)
 	char *name_mute, *name_micmute;
 	int i;
 
+	/*
+	 * Only register extra settings against subdevice where input_mapping
+	 * set drvdata to 1, i.e. the trackpoint.
+	 */
+	if (!hid_get_drvdata(hdev))
+		return 0;
+
+	hid_set_drvdata(hdev, NULL);
+
 	/* Validate required reports. */
 	for (i = 0; i < 4; i++) {
 		if (!hid_validate_values(hdev, HID_FEATURE_REPORT, 4, i, 1))
@@ -409,12 +432,16 @@ static int lenovo_probe(struct hid_device *hdev,
 		goto err;
 	}
 
-	if (hid_get_drvdata(hdev)) {
-		hid_set_drvdata(hdev, NULL);
+	switch (hdev->product) {
+	case USB_DEVICE_ID_LENOVO_TPKBD:
 		ret = lenovo_probe_tpkbd(hdev);
-		if (ret)
-			goto err_hid;
+		break;
+	default:
+		ret = 0;
+		break;
 	}
+	if (ret)
+		goto err_hid;
 
 	return 0;
 err_hid:
@@ -427,6 +454,13 @@ static void lenovo_remove_tpkbd(struct hid_device *hdev)
 {
 	struct lenovo_drvdata_tpkbd *data_pointer = hid_get_drvdata(hdev);
 
+	/*
+	 * Only the trackpoint half of the keyboard has drvdata and stuff that
+	 * needs unregistering.
+	 */
+	if (data_pointer == NULL)
+		return;
+
 	sysfs_remove_group(&hdev->dev.kobj,
 			&lenovo_attr_group_tpkbd);
 
@@ -438,8 +472,11 @@ static void lenovo_remove_tpkbd(struct hid_device *hdev)
 
 static void lenovo_remove(struct hid_device *hdev)
 {
-	if (hid_get_drvdata(hdev))
+	switch (hdev->product) {
+	case USB_DEVICE_ID_LENOVO_TPKBD:
 		lenovo_remove_tpkbd(hdev);
+		break;
+	}
 
 	hid_hw_stop(hdev);
 }
@@ -454,7 +491,7 @@ MODULE_DEVICE_TABLE(hid, lenovo_devices);
 static struct hid_driver lenovo_driver = {
 	.name = "lenovo",
 	.id_table = lenovo_devices,
-	.input_mapping = lenovo_input_mapping_tpkbd,
+	.input_mapping = lenovo_input_mapping,
 	.probe = lenovo_probe,
 	.remove = lenovo_remove,
 };