[PATCH] HID: nintendo: register input device after capabilities are set

[Jiangshan Yi]

input_register_device() exposes the device to userspace immediately.
In joycon_input_create() it was called before joycon_config_rumble()
configures the FF_RUMBLE capability and the memless force-feedback
device, so a concurrent EVIOCSFF could dereference a NULL dev->ff.

Registering early also means the initial udev event lacks button and
axis information, which can make input managers ignore the device.

Move input_register_device() to the end of joycon_input_create(), after
all capabilities, the IMU input device and the force-feedback callbacks
have been configured.

Fixes: 2af16c1f846b ("HID: nintendo: add nintendo switch controller driver")
Reported-by: sashiko-bot@xxxxxxxxxx
Closes: https://sashiko.dev/#/patchset/20260730031927.25444-1-yijiangshan@xxxxxxxxxx?part=1
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Jiangshan Yi <yijiangshan@xxxxxxxxxx>
---
 drivers/hid/hid-nintendo.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/hid/hid-nintendo.c b/drivers/hid/hid-nintendo.c
index e7302ec01ff1..7f014f371800 100644
--- a/drivers/hid/hid-nintendo.c
+++ b/drivers/hid/hid-nintendo.c
@@ -2162,10 +2162,6 @@ static int joycon_input_create(struct joycon_ctlr *ctlr)
 	ctlr->input->phys = hdev->phys;
 	input_set_drvdata(ctlr->input, ctlr);
 
-	ret = input_register_device(ctlr->input);
-	if (ret)
-		return ret;
-
 	if (joycon_type_is_right_joycon(ctlr)) {
 		joycon_config_right_stick(ctlr->input);
 		joycon_config_buttons(ctlr->input, right_joycon_button_mappings);
@@ -2208,6 +2204,10 @@ static int joycon_input_create(struct joycon_ctlr *ctlr)
 	if (joycon_has_rumble(ctlr))
 		joycon_config_rumble(ctlr);
 
+	ret = input_register_device(ctlr->input);
+	if (ret)
+		return ret;
+
 	return 0;
 }
 
-- 
2.25.1