staging: comedi: comedi_test: allow read-back of AO channels
COMEDI drivers often allow the last value written to a channel on an
analog output subdevice to be read back via the "insn_read" handler.
The "comedi_test" driver does not currently support that. It is a bit
special because it loops back the last values written to the channel on
the analog output subdevice to be read back via corresponding channels
on the analog input subdevice. The "insn_read" handler for the analog
input subdevice is `waveform_ai_insn_read()`. Set that as the
"insn_read" handler for the analog output subdevice as well.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/staging/comedi/drivers/comedi_test.c b/drivers/staging/comedi/drivers/comedi_test.c
index a750f84..468847a 100644
--- a/drivers/staging/comedi/drivers/comedi_test.c
+++ b/drivers/staging/comedi/drivers/comedi_test.c
@@ -457,6 +457,7 @@
s->maxdata = 0xffff;
s->range_table = &waveform_ai_ranges;
s->insn_write = waveform_ao_insn_write;
+ s->insn_read = waveform_ai_insn_read; /* do same as AI insn_read */
/* Our default loopback value is just a 0V flatline */
for (i = 0; i < s->n_chan; i++)