staging: comedi: das1800: use comedi_offset_munge() for analog output

The analog outputs expect 2's complement data. For aesthetics, use
the helper function to handle the munging instead of depending on
the boardinfo 'resolution'.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/das1800.c b/drivers/staging/comedi/drivers/das1800.c
index 6795f3e..f870824 100644 (file)
--- a/drivers/staging/comedi/drivers/das1800.c
+++ b/drivers/staging/comedi/drivers/das1800.c
@@ -1132,8 +1132,7 @@ static int das1800_ao_insn_write(struct comedi_device *dev,
        unsigned short output;
        unsigned long irq_flags;
 
-       /*   card expects two's complement data */
-       output = data[0] - (1 << (board->resolution - 1));
+       output = comedi_offset_munge(s, data[0]);
        /*  if the write is to the 'update' channel, we need to remember its value */
        if (chan == update_chan)
                devpriv->ao_update_bits = output;