diff options
| -rw-r--r-- | drivers/staging/comedi/drivers/pcmuio.c | 35 |
1 files changed, 20 insertions, 15 deletions
diff --git a/drivers/staging/comedi/drivers/pcmuio.c b/drivers/staging/comedi/drivers/pcmuio.c index fb0cbf047501..2dca1199d175 100644 --- a/drivers/staging/comedi/drivers/pcmuio.c +++ b/drivers/staging/comedi/drivers/pcmuio.c @@ -202,30 +202,35 @@ static unsigned int pcmuio_read(struct comedi_device *dev, */ static int pcmuio_dio_insn_bits(struct comedi_device *dev, struct comedi_subdevice *s, - struct comedi_insn *insn, unsigned int *data) + struct comedi_insn *insn, + unsigned int *data) { - unsigned int mask = data[0] & s->io_bits; /* outputs only */ - unsigned int bits = data[1]; + unsigned int chanmask = (1 << s->n_chan) - 1; int asic = s->index / 2; int port = (s->index % 2) ? 3 : 0; + unsigned int mask; unsigned int val; - /* get inverted state of the channels from the port */ - val = pcmuio_read(dev, asic, 0, port); - - /* get the true state of the channels */ - s->state = val ^ ((0x1 << s->n_chan) - 1); - + mask = comedi_dio_update_state(s, data); if (mask) { - s->state &= ~mask; - s->state |= (mask & bits); - - /* invert the state and update the channels */ - val = s->state ^ ((0x1 << s->n_chan) - 1); + /* + * Outputs are inverted, invert the state and + * update the channels. + * + * The s->io_bits mask makes sure the input channels + * are '0' so that the outputs pins stay in a high + * z-state. + */ + val = ~s->state & chanmask; + val &= s->io_bits; pcmuio_write(dev, val, asic, 0, port); } - data[1] = s->state; + /* get inverted state of the channels from the port */ + val = pcmuio_read(dev, asic, 0, port); + + /* return the true state of the channels */ + data[1] = ~val & chanmask; return insn->n; } |