[PATCH 4.9 07/66] HID: cp2112: fix gpio-callback error handling

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Johan Hovold <johan@xxxxxxxxxx>

commit 8e9faa15469ed7c7467423db4c62aeed3ff4cae3 upstream.

In case of a zero-length report, the gpio direction_input callback would
currently return success instead of an errno.

Fixes: 1ffb3c40ffb5 ("HID: cp2112: make transfer buffers DMA capable")
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/hid/hid-cp2112.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/hid/hid-cp2112.c
+++ b/drivers/hid/hid-cp2112.c
@@ -206,7 +206,7 @@ static int cp2112_gpio_direction_input(s
 
 exit:
 	mutex_unlock(&dev->lock);
-	return ret <= 0 ? ret : -EIO;
+	return ret < 0 ? ret : -EIO;
 }
 
 static void cp2112_gpio_set(struct gpio_chip *chip, unsigned offset, int value)