HID: multitouch: devm conversion

HID special drivers can use safely the devres API.
Use it to remove 25 lines of code and to clean up a little the error paths.

Besides the basic kzalloc -> devm_kzalloc conversions, I changed the
place of the allocation of the new name. Doing this right in
mt_input_configured() removes the kstrdup call which was not very helpful
and the new way is simpler to understand (and to debug).

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-multitouch.c

@@ -261,17 +261,6 @@ static struct mt_class mt_classes[] = {
 	{ }
 };
 
-static void mt_free_input_name(struct hid_input *hi)
-{
-	struct hid_device *hdev = hi->report->device;
-	const char *name = hi->input->name;
-
-	if (name != hdev->name) {
-		hi->input->name = hdev->name;
-		kfree(name);
-	}
-}
-
 static ssize_t mt_show_quirks(struct device *dev,
 			   struct device_attribute *attr,
 			   char *buf)
@@ -415,13 +404,6 @@ static void mt_pen_report(struct hid_device *hid, struct hid_report *report)
 static void mt_pen_input_configured(struct hid_device *hdev,
 					struct hid_input *hi)
 {
-	char *name = kzalloc(strlen(hi->input->name) + 5, GFP_KERNEL);
-	if (name) {
-		sprintf(name, "%s Pen", hi->input->name);
-		mt_free_input_name(hi);
-		hi->input->name = name;
-	}
-
 	/* force BTN_STYLUS to allow tablet matching in udev */
 	__set_bit(BTN_STYLUS, hi->input->keybit);
 }
@@ -928,24 +910,33 @@ static void mt_post_parse(struct mt_device *td)
 static void mt_input_configured(struct hid_device *hdev, struct hid_input *hi)
 {
 	struct mt_device *td = hid_get_drvdata(hdev);
-	char *name = kstrdup(hdev->name, GFP_KERNEL);
-
-	if (name)
-		hi->input->name = name;
+	char *name;
+	const char *suffix = NULL;
 
 	if (hi->report->id == td->mt_report_id)
 		mt_touch_input_configured(hdev, hi);
 
-	if (hi->report->id == td->pen_report_id)
+	if (hi->report->field[0]->physical == HID_DG_STYLUS) {
+		suffix = "Pen";
 		mt_pen_input_configured(hdev, hi);
+	}
+
+	if (suffix) {
+		name = devm_kzalloc(&hi->input->dev,
+				    strlen(hdev->name) + strlen(suffix) + 2,
+				    GFP_KERNEL);
+		if (name) {
+			sprintf(name, "%s %s", hdev->name, suffix);
+			hi->input->name = name;
+		}
+	}
 }
 
 static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 {
 	int ret, i;
 	struct mt_device *td;
 	struct mt_class *mtclass = mt_classes; /* MT_CLS_DEFAULT */
-	struct hid_input *hi;
 
 	for (i = 0; mt_classes[i].name ; i++) {
 		if (id->driver_data == mt_classes[i].name) {
@@ -967,7 +958,7 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	hdev->quirks |= HID_QUIRK_MULTI_INPUT;
 	hdev->quirks |= HID_QUIRK_NO_EMPTY_INPUT;
 
-	td = kzalloc(sizeof(struct mt_device), GFP_KERNEL);
+	td = devm_kzalloc(&hdev->dev, sizeof(struct mt_device), GFP_KERNEL);
 	if (!td) {
 		dev_err(&hdev->dev, "cannot allocate multitouch data\n");
 		return -ENOMEM;
@@ -980,41 +971,34 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	td->pen_report_id = -1;
 	hid_set_drvdata(hdev, td);
 
-	td->fields = kzalloc(sizeof(struct mt_fields), GFP_KERNEL);
+	td->fields = devm_kzalloc(&hdev->dev, sizeof(struct mt_fields),
+				  GFP_KERNEL);
 	if (!td->fields) {
 		dev_err(&hdev->dev, "cannot allocate multitouch fields data\n");
-		ret = -ENOMEM;
-		goto fail;
+		return -ENOMEM;
 	}
 
 	if (id->vendor == HID_ANY_ID && id->product == HID_ANY_ID)
 		td->serial_maybe = true;
 
 	ret = hid_parse(hdev);
 	if (ret != 0)
-		goto fail;
+		return ret;
 
 	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
 	if (ret)
-		goto hid_fail;
+		return ret;
 
 	ret = sysfs_create_group(&hdev->dev.kobj, &mt_attribute_group);
 
 	mt_set_maxcontacts(hdev);
 	mt_set_input_mode(hdev);
 
-	kfree(td->fields);
+	/* release .fields memory as it is not used anymore */
+	devm_kfree(&hdev->dev, td->fields);
 	td->fields = NULL;
 
 	return 0;
-
-hid_fail:
-	list_for_each_entry(hi, &hdev->inputs, list)
-		mt_free_input_name(hi);
-fail:
-	kfree(td->fields);
-	kfree(td);
-	return ret;
 }
 
 #ifdef CONFIG_PM
@@ -1039,17 +1023,8 @@ static int mt_resume(struct hid_device *hdev)
 
 static void mt_remove(struct hid_device *hdev)
 {
-	struct mt_device *td = hid_get_drvdata(hdev);
-	struct hid_input *hi;
-
 	sysfs_remove_group(&hdev->dev.kobj, &mt_attribute_group);
-	list_for_each_entry(hi, &hdev->inputs, list)
-		mt_free_input_name(hi);
-
 	hid_hw_stop(hdev);
-
-	kfree(td);
-	hid_set_drvdata(hdev, NULL);
 }
 
 static const struct hid_device_id mt_devices[] = {