From beecd01b720f3d907a5eacfc142090cf06326836 Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Thu, 5 Dec 2013 16:54:08 -0700 Subject: [PATCH] staging: comedi: pcmuio: fix pcmuio_dio_insn_bits() This dio subdevice (*insn_bits) function does not follow the "norm" for comedi drivers. It also _appears_ to return the incorrect state of the channels. Use the comedi_dio_update_state() helper to handle the boilerplate for updating the output channel state. Due to the hardware we then need to invert the state and mask the input channels before updating the outputs. Then read the hardware and invert the result to get the current true state of the dio channels. Signed-off-by: H Hartley Sweeten Cc: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/pcmuio.c | 35 +++++++++++++++++++-------------- 1 file changed, 20 insertions(+), 15 deletions(-) diff --git a/drivers/staging/comedi/drivers/pcmuio.c b/drivers/staging/comedi/drivers/pcmuio.c index fb0cbf0..2dca119 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; } -- 2.7.4