[PATCH] mfd: twl-core: unregister the auxiliary platform device on unbind

[Myeonghun Pak]

twl_probe() registers a standalone platform device named "twl", but keeps
its pointer only in a local variable. Probe errors unregister the device,
while successful probe leaves no way for twl_remove() to release it. The
platform device therefore remains registered after the I2C driver unbinds.

Register a managed action on the I2C device immediately after adding the
platform device. This unregisters it on probe failure and driver unbind,
and also handles failure to register the action itself. Remove the manual
error-path unregister to avoid releasing the device twice.

This issue was identified during our ongoing static-analysis research while
reviewing kernel code.

Fixes: defa6be1c821 ("mfd: Fix compile for twl-core.c by removing cpu_is_omap usage")
Cc: stable@xxxxxxxxxxxxxxx
Assisted-by: OpenAI:GPT-5.6
Co-developed-by: Ijae Kim <ae878000@xxxxxxxxx>
Signed-off-by: Ijae Kim <ae878000@xxxxxxxxx>
Signed-off-by: Myeonghun Pak <mhun512@xxxxxxxxx>
---
 drivers/mfd/twl-core.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/drivers/mfd/twl-core.c b/drivers/mfd/twl-core.c
index c024a28b0..128cd3f6c 100644
--- a/drivers/mfd/twl-core.c
+++ b/drivers/mfd/twl-core.c
@@ -719,6 +719,11 @@ static const struct mfd_cell twl6032_cells[] = {
 	{ .name = "twl6032-clk" },
 };
 
+static void twl_unregister_device(void *data)
+{
+	platform_device_unregister(data);
+}
+
 /* NOTE: This driver only handles a single twl4030/tps659x0 chip */
 static int
 twl_probe(struct i2c_client *client)
@@ -754,17 +759,22 @@ twl_probe(struct i2c_client *client)
 		return status;
 	}
 
+	status = devm_add_action_or_reset(&client->dev, twl_unregister_device,
+					  pdev);
+	if (status)
+		return status;
+
 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 		dev_dbg(&client->dev, "can't talk I2C?\n");
 		status = -EIO;
-		goto free;
+		goto out;
 	}
 
 	twl_priv = devm_kzalloc(&client->dev, sizeof(struct twl_private),
 				GFP_KERNEL);
 	if (!twl_priv) {
 		status = -ENOMEM;
-		goto free;
+		goto out;
 	}
 
 	if ((id->driver_data) & TWL6030_CLASS) {
@@ -784,7 +794,7 @@ twl_probe(struct i2c_client *client)
 					 GFP_KERNEL);
 	if (!twl_priv->twl_modules) {
 		status = -ENOMEM;
-		goto free;
+		goto out;
 	}
 
 	for (i = 0; i < num_slaves; i++) {
@@ -880,7 +890,7 @@ twl_probe(struct i2c_client *client)
 		status = devm_mfd_add_devices(&client->dev, PLATFORM_DEVID_NONE,
 					      cells, num_cells, NULL, 0, NULL);
 		if (status < 0)
-			goto free;
+			goto out;
 
 		if (of_device_is_system_power_controller(node)) {
 			if (!pm_power_off)
@@ -896,10 +906,7 @@ twl_probe(struct i2c_client *client)
 fail:
 	if (status < 0)
 		twl_remove(client);
-free:
-	if (status < 0)
-		platform_device_unregister(pdev);
-
+out:
 	return status;
 }
 
-- 
2.39.5