Input: adc-joystick - fix ordering in adc_joystick_probe()

We should register the IIO buffer before we register the input device,
because as soon as the device is registered input handlers may attach to
it, resulting in a call to adc_joystick_open() which makes use of the said
buffer.
Acked-by: Artur Rojek <contact@artur-rojek.eu>
Link: https://lore.kernel.org/r/YskFh4NHnlcryMkk@google.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/joystick/adc-joystick.c

@@ -222,13 +222,6 @@ static int adc_joystick_probe(struct platform_device *pdev)
 	if (error)
 		return error;
 
-	input_set_drvdata(input, joy);
-	error = input_register_device(input);
-	if (error) {
-		dev_err(dev, "Unable to register input device\n");
-		return error;
-	}
-
 	joy->buffer = iio_channel_get_all_cb(dev, adc_joystick_handle, joy);
 	if (IS_ERR(joy->buffer)) {
 		dev_err(dev, "Unable to allocate callback buffer\n");
@@ -241,6 +234,14 @@ static int adc_joystick_probe(struct platform_device *pdev)
 		return error;
 	}
 
+	input_set_drvdata(input, joy);
+
+	error = input_register_device(input);
+	if (error) {
+		dev_err(dev, "Unable to register input device\n");
+		return error;
+	}
+
 	return 0;
 }