[PATCH 4.9 09/20] nfc: port100: fix using -ERRNO as command type mask

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>

commit 2195f2062e4cc93870da8e71c318ef98a1c51cef upstream.

During probing, the driver tries to get a list (mask) of supported
command types in port100_get_command_type_mask() function.  The value
is u64 and 0 is treated as invalid mask (no commands supported).  The
function however returns also -ERRNO as u64 which will be interpret as
valid command mask.

Return 0 on every error case of port100_get_command_type_mask(), so the
probing will stop.

Cc: <stable@vger.kernel.org>
Fixes: 0347a6ab300a ("NFC: port100: Commands mechanism implementation")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/nfc/port100.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/nfc/port100.c
+++ b/drivers/nfc/port100.c
@@ -1011,11 +1011,11 @@ static u64 port100_get_command_type_mask
 
 	skb = port100_alloc_skb(dev, 0);
 	if (!skb)
-		return -ENOMEM;
+		return 0;
 
 	resp = port100_send_cmd_sync(dev, PORT100_CMD_GET_COMMAND_TYPE, skb);
 	if (IS_ERR(resp))
-		return PTR_ERR(resp);
+		return 0;
 
 	if (resp->len < 8)
 		mask = 0;