The maximum differential channel is half the subdevice 'n_chan'. Use
that instead and remove the need for the 'board' variable.
Also, the comedi core does no validate the aref flags. Add a check
to ensure that the subdevice actually supports the AREF_DIFF mode.
Signed-off-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
Cc: Ian Abbott <abbotti@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/comedi/drivers/me4000.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/staging/comedi/drivers/me4000.c b/drivers/staging/comedi/drivers/me4000.c
index 335fafc..008929e 100644
--- a/drivers/staging/comedi/drivers/me4000.c
+++ b/drivers/staging/comedi/drivers/me4000.c
@@ -568,8 +568,6 @@ static int me4000_ai_check_chanlist(struct comedi_device *dev,
struct comedi_subdevice *s,
struct comedi_cmd *cmd)
{
- const struct me4000_board *board = dev->board_ptr;
- unsigned int max_diff_chan = board->ai_diff_nchan;
unsigned int aref0 = CR_AREF(cmd->chanlist[0]);
int i;
@@ -585,7 +583,13 @@ static int me4000_ai_check_chanlist(struct comedi_device *dev,
}
if (aref == AREF_DIFF) {
- if (chan >= max_diff_chan) {
+ if (!(s->subdev_flags && SDF_DIFF)) {
+ dev_err(dev->class_dev,
+ "Differential inputs are not available\n");
+ return -EINVAL;
+ }
+
+ if (chan >= (s->n_chan / 2)) {
dev_dbg(dev->class_dev,
"Channel number to high\n");
return -EINVAL;
--
2.4.3
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