staging: comedi: ni_mio_common: fix the (*insn_write) for the freq_out counter

The (*insn_write) functions are supposed to write insn->n data values and
return the number of values written. For this subdevice it only makes sense
to write the last data value.

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/ni_mio_common.c b/drivers/staging/comedi/drivers/ni_mio_common.c
index 6536d68..69be8ea 100644 (file)
--- a/drivers/staging/comedi/drivers/ni_mio_common.c
+++ b/drivers/staging/comedi/drivers/ni_mio_common.c
@@ -3888,18 +3888,24 @@ static int ni_freq_out_insn_read(struct comedi_device *dev,
 
 static int ni_freq_out_insn_write(struct comedi_device *dev,
                                  struct comedi_subdevice *s,
-                                 struct comedi_insn *insn, unsigned int *data)
+                                 struct comedi_insn *insn,
+                                 unsigned int *data)
 {
        struct ni_private *devpriv = dev->private;
 
-       devpriv->clock_and_fout &= ~FOUT_Enable;
-       devpriv->stc_writew(dev, devpriv->clock_and_fout,
-                           Clock_and_FOUT_Register);
-       devpriv->clock_and_fout &= ~FOUT_Divider_mask;
-       devpriv->clock_and_fout |= FOUT_Divider(data[0]);
-       devpriv->clock_and_fout |= FOUT_Enable;
-       devpriv->stc_writew(dev, devpriv->clock_and_fout,
-                           Clock_and_FOUT_Register);
+       if (insn->n) {
+               devpriv->clock_and_fout &= ~FOUT_Enable;
+               devpriv->stc_writew(dev, devpriv->clock_and_fout,
+                                   Clock_and_FOUT_Register);
+               devpriv->clock_and_fout &= ~FOUT_Divider_mask;
+
+               /* use the last data value to set the fout divider */
+               devpriv->clock_and_fout |= FOUT_Divider(data[insn->n - 1]);
+
+               devpriv->clock_and_fout |= FOUT_Enable;
+               devpriv->stc_writew(dev, devpriv->clock_and_fout,
+                                   Clock_and_FOUT_Register);
+       }
        return insn->n;
 }