[PATCH 3/4] Input: sur40 - factor out and move input device initialization

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

The input device allocation, setup, and registration in sur40_probe() is
quite verbose. Factor it out into a helper function sur40_init_input() to
improve readability.

Additionally, call this helper at the very end of sur40_probe() instead of
allocating the input device early. This ensures all video components are fully
initialized before the input device is registered (which starts polling),
and simplifies the early probe error paths since we don't have to carry and
free the input device if probe fails during early V4L2 setup.

Reported-by: sashiko-bot@kernel.org
Cc: stable@vger.kernel.org
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/touchscreen/sur40.c | 91 +++++++++++++++++--------------
 1 file changed, 50 insertions(+), 41 deletions(-)

diff --git a/drivers/input/touchscreen/sur40.c b/drivers/input/touchscreen/sur40.c
index e9089b0c3e2f..1ad68131e3a6 100644
--- a/drivers/input/touchscreen/sur40.c
+++ b/drivers/input/touchscreen/sur40.c
@@ -647,6 +647,53 @@ static int sur40_input_setup_events(struct input_dev *input_dev)
 	return 0;
 }
 
+static int sur40_init_input(struct sur40_state *sur40)
+{
+	struct input_dev *input;
+	int error;
+
+	input = input_allocate_device();
+	if (!input)
+		return -ENOMEM;
+
+	/* Set up regular input device structure */
+	input->name = DRIVER_LONG;
+	usb_to_input_id(sur40->usbdev, &input->id);
+	usb_make_path(sur40->usbdev, sur40->phys, sizeof(sur40->phys));
+	strlcat(sur40->phys, "/input0", sizeof(sur40->phys));
+	input->phys = sur40->phys;
+	input->dev.parent = sur40->dev;
+
+	input->open = sur40_open;
+	input->close = sur40_close;
+
+	error = sur40_input_setup_events(input);
+	if (error)
+		goto err_free_input;
+
+	input_set_drvdata(input, sur40);
+	error = input_setup_polling(input, sur40_poll);
+	if (error) {
+		dev_err(sur40->dev, "failed to set up polling\n");
+		goto err_free_input;
+	}
+
+	input_set_poll_interval(input, POLL_INTERVAL);
+
+	error = input_register_device(input);
+	if (error) {
+		dev_err(sur40->dev, "Unable to register polled input device.\n");
+		goto err_free_input;
+	}
+
+	sur40->input = input;
+	return 0;
+
+err_free_input:
+	input_free_device(input);
+	return error;
+}
+
 /* Check candidate USB interface. */
 static int sur40_probe(struct usb_interface *interface,
 		       const struct usb_device_id *id)
@@ -655,7 +702,6 @@ static int sur40_probe(struct usb_interface *interface,
 	struct sur40_state *sur40;
 	struct usb_host_interface *iface_desc;
 	struct usb_endpoint_descriptor *endpoint;
-	struct input_dev *input;
 	int error;
 
 	/* Check if we really have the right interface. */
@@ -676,44 +722,13 @@ static int sur40_probe(struct usb_interface *interface,
 	if (!sur40)
 		return -ENOMEM;
 
-	input = input_allocate_device();
-	if (!input) {
-		error = -ENOMEM;
-		goto err_free_dev;
-	}
-
 	/* initialize locks/lists */
 	INIT_LIST_HEAD(&sur40->buf_list);
 	spin_lock_init(&sur40->qlock);
 	mutex_init(&sur40->lock);
 
-	/* Set up regular input device structure */
-	input->name = DRIVER_LONG;
-	usb_to_input_id(usbdev, &input->id);
-	usb_make_path(usbdev, sur40->phys, sizeof(sur40->phys));
-	strlcat(sur40->phys, "/input0", sizeof(sur40->phys));
-	input->phys = sur40->phys;
-	input->dev.parent = &interface->dev;
-
-	input->open = sur40_open;
-	input->close = sur40_close;
-
-	error = sur40_input_setup_events(input);
-	if (error)
-		goto err_free_input;
-
-	input_set_drvdata(input, sur40);
-	error = input_setup_polling(input, sur40_poll);
-	if (error) {
-		dev_err(&interface->dev, "failed to set up polling");
-		goto err_free_input;
-	}
-
-	input_set_poll_interval(input, POLL_INTERVAL);
-
 	sur40->usbdev = usbdev;
 	sur40->dev = &interface->dev;
-	sur40->input = input;
 
 	/* use the bulk-in endpoint tested above */
 	sur40->bulk_in_size = usb_endpoint_maxp(endpoint);
@@ -722,7 +737,7 @@ static int sur40_probe(struct usb_interface *interface,
 	if (!sur40->bulk_in_buffer) {
 		dev_err(&interface->dev, "Unable to allocate input buffer.");
 		error = -ENOMEM;
-		goto err_free_input;
+		goto err_free_dev;
 	}
 
 	/* register the video master device */
@@ -790,13 +805,9 @@ static int sur40_probe(struct usb_interface *interface,
 		goto err_free_ctrl;
 	}
 
-	/* register the polled input device */
-	error = input_register_device(input);
-	if (error) {
-		dev_err(&interface->dev,
-			"Unable to register polled input device.");
+	error = sur40_init_input(sur40);
+	if (error)
 		goto err_unreg_video;
-	}
 
 	/* we can register the device now, as it is ready */
 	usb_set_intfdata(interface, sur40);
@@ -812,8 +823,6 @@ static int sur40_probe(struct usb_interface *interface,
 	v4l2_device_unregister(&sur40->v4l2);
 err_free_buffer:
 	kfree(sur40->bulk_in_buffer);
-err_free_input:
-	input_free_device(input);
 err_free_dev:
 	kfree(sur40);
 
-- 
2.54.0.1136.gdb2ca164c4-goog