staging: comedi: usbduxsigma: round down AO scan_begin_arg at step 4.

The return value of the `cmdtest` handler for a subdevice checks the
prospective new command in various steps and returns the step number at
which any problem was detected, or 0 if no problem was detected.  It is
allowed to modify the command in various ways at each step.  Corrections
for out-of-range values are generally made at step 3, and minor
adjustments such as rounding are generally made at step 4.

The `cmdtest` handler for the AO subdevice (`usbduxsigma_ao_cmdtest()`)
currently range checks the timings at step 3.  Since the running command
will round down the timings, add code to round them down at step 4.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: Bernd Porr <mail@berndporr.me.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/usbduxsigma.c b/drivers/staging/comedi/drivers/usbduxsigma.c
index 9f43e01b58c5dbe477af89b2cf9257824a8fa7ce..649cf47184a403241badec00b70164657a7054bd 100644 (file)
--- a/drivers/staging/comedi/drivers/usbduxsigma.c
+++ b/drivers/staging/comedi/drivers/usbduxsigma.c
@@ -839,6 +839,7 @@ static int usbduxsigma_ao_cmdtest(struct comedi_device *dev,
                                  struct comedi_cmd *cmd)
 {
        struct usbduxsigma_private *devpriv = dev->private;
+       unsigned int tmp;
        int err = 0;
 
        /* Step 1 : check if triggers are trivially valid */
@@ -890,6 +891,14 @@ static int usbduxsigma_ao_cmdtest(struct comedi_device *dev,
        if (err)
                return 3;
 
+       /* Step 4: fix up any arguments */
+
+       tmp = rounddown(cmd->scan_begin_arg, 1000000);
+       err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, tmp);
+
+       if (err)
+               return 4;
+
        return 0;
 }