[PATCH 28/29] staging: comedi: dt282x: fix bug where DIO direction is reset to inputs
H Hartley Sweeten
hsweeten at visionengravers.com
Fri Jun 20 20:13:01 UTC 2014
The direction of the 16 DIO channels is controlled with two bits in the
DACSR register. The HBOE bit controls the direction of channels 15-8 and
the LBOE bit channels 7-0.
The DACSR register is also used to control the Analog Output async command
support. Currently, starting or canceling an Analog Output command would
also reset the DIO directions so that all channels were inputs.
Fix the driver so that the DIO direction is not changed when starting or
canceling an Analog Output async command.
Signed-off-by: H Hartley Sweeten <hsweeten at visionengravers.com>
Cc: Ian Abbott <abbotti at mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
---
drivers/staging/comedi/drivers/dt282x.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/staging/comedi/drivers/dt282x.c b/drivers/staging/comedi/drivers/dt282x.c
index 6e813bb..e30a064 100644
--- a/drivers/staging/comedi/drivers/dt282x.c
+++ b/drivers/staging/comedi/drivers/dt282x.c
@@ -993,9 +993,12 @@ static int dt282x_ao_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
outw(devpriv->divisor, dev->iobase + DT2821_TMRCTR_REG);
- devpriv->dacsr = DT2821_DACSR_SSEL |
- DT2821_DACSR_DACLK |
- DT2821_DACSR_IDARDY;
+ /* clear all bits but the DIO direction bits */
+ devpriv->dacsr &= (DT2821_DACSR_LBOE | DT2821_DACSR_HBOE);
+
+ devpriv->dacsr |= (DT2821_DACSR_SSEL |
+ DT2821_DACSR_DACLK |
+ DT2821_DACSR_IDARDY);
outw(devpriv->dacsr, dev->iobase + DT2821_DACSR_REG);
s->async->inttrig = dt282x_ao_inttrig;
@@ -1010,7 +1013,9 @@ static int dt282x_ao_cancel(struct comedi_device *dev,
dt282x_disable_dma(dev);
- devpriv->dacsr = 0;
+ /* clear all bits but the DIO direction bits */
+ devpriv->dacsr &= (DT2821_DACSR_LBOE | DT2821_DACSR_HBOE);
+
outw(devpriv->dacsr, dev->iobase + DT2821_DACSR_REG);
devpriv->supcsr = 0;
--
1.9.3
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