staging: comedi: comedidev.h: introduce some 'range_is_external' helpers

The comedi_krange includes a flags member that currently identifies the
'units' of the range (RF_UNIT) and if the range is from an internal or
external source (RF_EXTERNAL).

Introduce some helper functions to check if a given range is from an
external source.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/comedidev.h

@@ -363,6 +363,12 @@ static inline bool comedi_range_is_unipolar(struct comedi_subdevice *s,
 	return s->range_table->range[range].min >= 0;
 }
 
+static inline bool comedi_range_is_external(struct comedi_subdevice *s,
+					    unsigned int range)
+{
+	return !!(s->range_table->range[range].flags & RF_EXTERNAL);
+}
+
 static inline bool comedi_chan_range_is_bipolar(struct comedi_subdevice *s,
 						unsigned int chan,
 						unsigned int range)
@@ -377,6 +383,13 @@ static inline bool comedi_chan_range_is_unipolar(struct comedi_subdevice *s,
 	return s->range_table_list[chan]->range[range].min >= 0;
 }
 
+static inline bool comedi_chan_range_is_external(struct comedi_subdevice *s,
+						 unsigned int chan,
+						 unsigned int range)
+{
+	return !!(s->range_table_list[chan]->range[range].flags & RF_EXTERNAL);
+}
+
 /* munge between offset binary and two's complement values */
 static inline unsigned int comedi_offset_munge(struct comedi_subdevice *s,
 					       unsigned int val)