[PATCH 1/5] staging: comedi: das16: simplify cmd->scan_begin_src validation

[H Hartley Sweeten]

The analog input (*do_cmdtest) in this driver currently validates that the
scan_begin_src is TRIG_FOLLOW or, if the board can_burst, TRIG_TIMER or TRIG_EXT.
The rest of the driver is coded to assume that the scan_begin_src is always
TRIG_FOLLOW.

Simplify the driver by removing the, unused, TRIG_TIMER and TRIG_EXT options
and validation.

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/das16.c | 34 ++++------------------------------
 1 file changed, 4 insertions(+), 30 deletions(-)

diff --git a/drivers/staging/comedi/drivers/das16.c b/drivers/staging/comedi/drivers/das16.c
index 4608b01..5523278 100644
--- a/drivers/staging/comedi/drivers/das16.c
+++ b/drivers/staging/comedi/drivers/das16.c
@@ -592,11 +592,7 @@ static int das16_cmd_test(struct comedi_device *dev, struct comedi_subdevice *s,
 	/* Step 1 : check if triggers are trivially valid */
 
 	err |= cfc_check_trigger_src(&cmd->start_src, TRIG_NOW);
-
-	trig_mask = TRIG_FOLLOW;
-	if (devpriv->can_burst)
-		trig_mask |= TRIG_TIMER | TRIG_EXT;
-	err |= cfc_check_trigger_src(&cmd->scan_begin_src, trig_mask);
+	err |= cfc_check_trigger_src(&cmd->scan_begin_src, TRIG_FOLLOW);
 
 	trig_mask = TRIG_TIMER | TRIG_EXT;
 	if (devpriv->can_burst)
@@ -611,35 +607,20 @@ static int das16_cmd_test(struct comedi_device *dev, struct comedi_subdevice *s,
 
 	/* Step 2a : make sure trigger sources are unique */
 
-	err |= cfc_check_trigger_is_unique(cmd->scan_begin_src);
 	err |= cfc_check_trigger_is_unique(cmd->convert_src);
 	err |= cfc_check_trigger_is_unique(cmd->stop_src);
 
 	/* Step 2b : and mutually compatible */
 
-	/*  make sure scan_begin_src and convert_src dont conflict */
-	if (cmd->scan_begin_src == TRIG_FOLLOW && cmd->convert_src == TRIG_NOW)
-		err |= -EINVAL;
-	if (cmd->scan_begin_src != TRIG_FOLLOW && cmd->convert_src != TRIG_NOW)
-		err |= -EINVAL;
-
 	if (err)
 		return 2;
 
 	/* Step 3: check if arguments are trivially valid */
 
 	err |= cfc_check_trigger_arg_is(&cmd->start_arg, 0);
-
-	if (cmd->scan_begin_src == TRIG_FOLLOW)	/* internal trigger */
-		err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, 0);
-
+	err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, 0);
 	err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len);
 
-	/* check against maximum frequency */
-	if (cmd->scan_begin_src == TRIG_TIMER)
-		err |= cfc_check_trigger_arg_min(&cmd->scan_begin_arg,
-					board->ai_speed * cmd->chanlist_len);
-
 	if (cmd->convert_src == TRIG_TIMER)
 		err |= cfc_check_trigger_arg_min(&cmd->convert_arg,
 						 board->ai_speed);
@@ -652,15 +633,8 @@ static int das16_cmd_test(struct comedi_device *dev, struct comedi_subdevice *s,
 	if (err)
 		return 3;
 
-	/*  step 4: fix up arguments */
-	if (cmd->scan_begin_src == TRIG_TIMER) {
-		arg = cmd->scan_begin_arg;
-		i8253_cascade_ns_to_timer(devpriv->clockbase,
-					  &devpriv->divisor1,
-					  &devpriv->divisor2,
-					  &arg, cmd->flags);
-		err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, arg);
-	}
+	/* Step 4: fix up arguments */
+
 	if (cmd->convert_src == TRIG_TIMER) {
 		arg = cmd->convert_arg;
 		i8253_cascade_ns_to_timer(devpriv->clockbase,
-- 
2.0.3