NFC: xmit from hci ops must return 0 or negative

xmit callback provided by a driver encapsulates upper layers
data and sends it to the hardware. So, HCI does not know the
exact amount of data being sent and thus can't handle partially
sent frames properly.

Therefore, the driver must return 0 for completely sent frame or
negative for failure.

Signed-off-by: Waldemar Rymarkiewicz <waldemar.rymarkiewicz@tieto.com>
Acked-by: Eric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/nfc/pn544_hci.c b/drivers/nfc/pn544_hci.c
index 7b0c2176e89b..c9c8570273ab 100644
--- a/drivers/nfc/pn544_hci.c
+++ b/drivers/nfc/pn544_hci.c
@@ -235,8 +235,12 @@ static int pn544_hci_i2c_write(struct i2c_client *client, u8 *buf, int len)
                 r = i2c_master_send(client, buf, len);
         }
 
-        if (r >= 0 && r != len)
-                r = -EREMOTEIO;
+        if (r >= 0) {
+                if (r != len)
+                        return -EREMOTEIO;
+                else
+                        return 0;
+        }
 
         return r;
 }