SPI controller drivers return number of bytes actually transfered from
bitbang->txrx_bufs() method. Returned zero number of bytes transfered
when non-zero number of bytes to transfer was requested should be
recognized as error.
The patch fixes that.

Signed-off-by: Jan Nikitenko <jan.nikitenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

---

 spi_bitbang.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)