Introduce a helper function to calculate the number of samples remaining
when the cmd->stop_src is TRIG_COUNT.
Signed-off-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Ian Abbott <abbotti@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/comedi/comedidev.h | 2 ++
drivers/staging/comedi/drivers.c | 32 ++++++++++++++++++++++++++++++++
2 files changed, 34 insertions(+)
diff --git a/drivers/staging/comedi/comedidev.h b/drivers/staging/comedi/comedidev.h
index e3ef5cc..a80cdfc 100644
--- a/drivers/staging/comedi/comedidev.h
+++ b/drivers/staging/comedi/comedidev.h
@@ -518,6 +518,8 @@ unsigned int comedi_dio_update_state(struct comedi_subdevice *,
unsigned int comedi_bytes_per_scan(struct comedi_subdevice *s);
unsigned int comedi_nscans_left(struct comedi_subdevice *s,
unsigned int nscans);
+unsigned int comedi_nsamples_left(struct comedi_subdevice *s,
+ unsigned int nsamples);
void comedi_inc_scan_progress(struct comedi_subdevice *s,
unsigned int num_bytes);
diff --git a/drivers/staging/comedi/drivers.c b/drivers/staging/comedi/drivers.c
index 00194a5..82ac845 100644
--- a/drivers/staging/comedi/drivers.c
+++ b/drivers/staging/comedi/drivers.c
@@ -367,6 +367,38 @@ unsigned int comedi_nscans_left(struct comedi_subdevice *s,
EXPORT_SYMBOL_GPL(comedi_nscans_left);
/**
+ * comedi_nsamples_left - return the number of samples left in the command
+ * @s: comedi_subdevice struct
+ * @nsamples: the expected number of samples
+ *
+ * Returns the expected number of samples of the number of samples remaining
+ * in the command.
+ */
+unsigned int comedi_nsamples_left(struct comedi_subdevice *s,
+ unsigned int nsamples)
+{
+ struct comedi_async *async = s->async;
+ struct comedi_cmd *cmd = &async->cmd;
+
+ if (cmd->stop_src == TRIG_COUNT) {
+ /* +1 to force comedi_nscans_left() to return the scans left */
+ unsigned int nscans = (nsamples / cmd->scan_end_arg) + 1;
+ unsigned int scans_left = comedi_nscans_left(s, nscans);
+ unsigned long long samples_left = 0;
+
+ if (scans_left) {
+ samples_left = ((unsigned long long)scans_left *
+ cmd->scan_end_arg) - async->cur_chan;
+ }
+
+ if (samples_left < nsamples)
+ nsamples = samples_left;
+ }
+ return nsamples;
+}
+EXPORT_SYMBOL_GPL(comedi_nsamples_left);
+
+/**
* comedi_inc_scan_progress - update scan progress in asynchronous command
* @s: comedi_subdevice struct
* @num_bytes: amount of data in bytes to increment scan progress
--
2.0.3
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