Commit 333e40ae authored Jul 23, 2015 by Ian Abbott Committed by Greg Kroah-Hartman Jul 24, 2015

staging: comedi: usbduxsigma: round down AI 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 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@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>

parent 12e1e696

drivers/staging/comedi/drivers/usbduxsigma.c

+8 −5

Original line number	Diff line number	Diff line
		@@ -519,17 +519,12 @@ 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);
		@@ -542,6 +537,14 @@ 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;
		}

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