[PATCH v3 23/24] staging: comedi: quatech_daqp_cs: ai async command requires a pacer

[H Hartley Sweeten]

The ai (*do_cmd) assumes that either the convert_src is TRIG_TIMER or
the scan_begin_src is TRIG_TIMER and always programs the pacer clock
with the appropriate trigger argument.

Add a Step 2b check to the (*do_cmdtest) to ensure that at least one
of the triggers is TRIG_TIMER.

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/quatech_daqp_cs.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/staging/comedi/drivers/quatech_daqp_cs.c b/drivers/staging/comedi/drivers/quatech_daqp_cs.c
index 0ea02f0..b56d126 100644
--- a/drivers/staging/comedi/drivers/quatech_daqp_cs.c
+++ b/drivers/staging/comedi/drivers/quatech_daqp_cs.c
@@ -394,6 +394,10 @@ static int daqp_ai_cmdtest(struct comedi_device *dev,
 
 	/* Step 2b : and mutually compatible */
 
+	/* the async command requires a pacer */
+	if (cmd->scan_begin_src != TRIG_TIMER && cmd->convert_src != TRIG_TIMER)
+		err |= -EINVAL;
+
 	if (err)
 		return 2;
 
-- 
2.5.1