All of the comedi drivers that support the 'cmd' callback also
require a 'do_cmdtest' callback. The do_cmdtest validates the
comedi_cmd before it is executed.
"Step 1" of each do_cmdtest does a trivial validation of the
trigger sources by doing something like this for each trigger:
int err = 0;
unsigned int tmp;
tmp = cmd->start_src;
src &= TRIG_NOW;
if (!src || tmp != src)
err++;
/* Test the remaining triggers similarly */
if (err)
return 1;
Introduce a helper function in comedi_fc to handle this boilerplate.
The drivers can then just do:
err |= cfc_check_trigger_src(&cmd->start_src, TRIG_NOW);
/* Test the remaining triggers similarly */
if (err)
return 1;
Signed-off-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
Cc: Ian Abbott <abbotti@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/comedi/drivers/comedi_fc.h | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/drivers/staging/comedi/drivers/comedi_fc.h b/drivers/staging/comedi/drivers/comedi_fc.h
index 4b2cfd3..1f08391 100644
--- a/drivers/staging/comedi/drivers/comedi_fc.h
+++ b/drivers/staging/comedi/drivers/comedi_fc.h
@@ -73,4 +73,24 @@ static inline unsigned int cfc_bytes_per_scan(struct comedi_subdevice *subd)
return num_samples * bytes_per_sample(subd);
}
+/**
+ * cfc_check_trigger_src() - trivially validate a comedi_cmd trigger source
+ * @src: pointer to the trigger source to validate
+ * @flags: bitmask of valid TRIG_* for the trigger
+ *
+ * This is used in "step 1" of the do_cmdtest functions of comedi drivers
+ * to vaildate the comedi_cmd triggers. The mask of the @src against the
+ * @flags allows the userspace comedilib to pass all the comedi_cmd
+ * triggers as TRIG_ANY and get back a bitmask of the valid trigger sources.
+ */
+static inline int cfc_check_trigger_src(unsigned int *src, unsigned int flags)
+{
+ unsigned int orig_src = *src;
+
+ *src = orig_src & flags;
+ if (*src == TRIG_INVALID || *src != orig_src)
+ return -EINVAL;
+ return 0;
+}
+
#endif /* _COMEDI_FC_H */
--
1.7.11
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