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 AI subdevice (`usbduxsigma_ai_cmdtest()`)
currently modifies `cmd->scan_begin_arg` to bring it into range and
round it down at step 3. Move the rounding down part to step 4 to
follow the usual Comedi convention.
Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx>
---
drivers/staging/comedi/drivers/usbduxsigma.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/staging/comedi/drivers/usbduxsigma.c b/drivers/staging/comedi/drivers/usbduxsigma.c
index 65a0df4..4655048 100644
--- a/drivers/staging/comedi/drivers/usbduxsigma.c
+++ b/drivers/staging/comedi/drivers/usbduxsigma.c
@@ -518,17 +518,12 @@ static int usbduxsigma_ai_cmdtest(struct comedi_device *dev,
*/
err |= comedi_check_trigger_arg_min(&cmd->scan_begin_arg,
(125000 * interval));
-
- tmp = (cmd->scan_begin_arg / 125000) * 125000;
} else {
/* full speed */
/* 1kHz scans every USB frame */
err |= comedi_check_trigger_arg_min(&cmd->scan_begin_arg,
1000000);
-
- tmp = (cmd->scan_begin_arg / 1000000) * 1000000;
}
- err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, tmp);
err |= comedi_check_trigger_arg_is(&cmd->scan_end_arg,
cmd->chanlist_len);
@@ -541,6 +536,14 @@ static int usbduxsigma_ai_cmdtest(struct comedi_device *dev,
if (err)
return 3;
+ /* Step 4: fix up any arguments */
+
+ tmp = rounddown(cmd->scan_begin_arg, high_speed ? 125000 : 1000000);
+ err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, tmp);
+
+ if (err)
+ return 4;
+
return 0;
}
--
2.1.4
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