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staging: comedi: rtd520: fix ai_read_n() async->cur_chan use

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This functions uses the async->cur_chan to determine if the current channel
is using a bipolar range and the sample needs to be munged. The cur_chan is
never incremented so all the samples are munged based on the fist channel
in the cmd->chanlist.

Bump the cur_chan after writing each sample. This fixes the code so that
the munging will be done correctly.

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>
This commit is contained in:
H Hartley Sweeten 2014-10-30 11:32:28 -07:00 • committed by Greg Kroah-Hartman
parent a7d3de75cf
commit 0c8c1c0ad8
1 changed files with 6 additions and 1 deletions
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7
drivers/staging/comedi/drivers/rtd520.c
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@ -606,6 +606,8 @@ static int ai_read_n(struct comedi_device *dev, struct comedi_subdevice *s,
int count)
{
struct rtd_private *devpriv = dev->private;
struct comedi_async *async = s->async;
struct comedi_cmd *cmd = &async->cmd;
int ii;
for (ii = 0; ii < count; ii++) {
@ -618,7 +620,7 @@ static int ai_read_n(struct comedi_device *dev, struct comedi_subdevice *s,
d = readw(devpriv->las1 + LAS1_ADC_FIFO);
d = d >> 3; /* low 3 bits are marker lines */
if (test_bit(s->async->cur_chan, devpriv->chan_is_bipolar))
if (test_bit(async->cur_chan, devpriv->chan_is_bipolar))
/* convert to comedi unsigned data */
d = comedi_offset_munge(s, d);
d &= s->maxdata;
@ -626,6 +628,9 @@ static int ai_read_n(struct comedi_device *dev, struct comedi_subdevice *s,
if (!comedi_buf_write_samples(s, &d, 1))
return -1;
async->cur_chan++;
async->cur_chan %= cmd->chanlist_len;
if (devpriv->ai_count > 0) /* < 0, means read forever */
devpriv->ai_count--;
}