[PATCH 2/5] platform/chrome: cros_ec_lpc: fix reference leak on failed device registration

[Vastargazing <vebohr@gmail.com>]

When platform_device_register() fails in cros_ec_lpc_init(), the embedded
struct device has already been initialized by device_initialize() inside
platform_device_register(). The error path unregisters the driver but
returns without dropping the device reference:

  cros_ec_lpc_init()
    -> platform_device_register(&cros_ec_lpc_device)
       -> device_initialize(&cros_ec_lpc_device.dev)   /* kref = 1 */
       -> platform_device_add(&cros_ec_lpc_device)     /* fails */
    <- platform_driver_unregister() called, but kref still 1

Per platform_device_register() kernel-doc:

  NOTE: _Never_ directly free @pdev after calling this function, even if
  it returned an error! Always use platform_device_put() to give up the
  reference initialised in this function instead.

Fix this by calling platform_device_put() before unregistering the driver.

Fixes: 5f454bdf6353 ("platform/chrome: cros_ec_lpc: Register the driver if ACPI entry is missing.")
Cc: stable@vger.kernel.org
Assisted-by: GitHub Copilot (Claude Sonnet 4.5)
Signed-off-by: Vastargazing <vebohr@gmail.com>
---
 drivers/platform/chrome/cros_ec_lpc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/platform/chrome/cros_ec_lpc.c b/drivers/platform/chrome/cros_ec_lpc.c
index 78cfff80cdea..cb3ff76d29e9 100644
--- a/drivers/platform/chrome/cros_ec_lpc.c
+++ b/drivers/platform/chrome/cros_ec_lpc.c
@@ -892,6 +892,7 @@ static int __init cros_ec_lpc_init(void)
 		ret = platform_device_register(&cros_ec_lpc_device);
 		if (ret) {
 			pr_err(DRV_NAME ": can't register device: %d\n", ret);
+			platform_device_put(&cros_ec_lpc_device);
 			platform_driver_unregister(&cros_ec_lpc_driver);
 		}
 	}
-- 
2.51.0