diff options
| author | H Hartley Sweeten <hsweeten@visionengravers.com> | 2014-11-05 10:31:33 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-11-07 09:29:41 -0800 |
| commit | f615915ee5faf74d8912df1694e810c8269f6b3f (patch) | |
| tree | 12db09c618ee6a64feddfc626b31552d1e988362 /drivers/staging | |
| parent | a65ccf634c91005bfc2c715b09aa43c1b18ce865 (diff) | |
staging: comedi: drivers: introduce comedi_nsamples_left()
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@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging')
| -rw-r--r-- | drivers/staging/comedi/comedidev.h | 2 | ||||
| -rw-r--r-- | drivers/staging/comedi/drivers.c | 32 |
2 files changed, 34 insertions, 0 deletions
diff --git a/drivers/staging/comedi/comedidev.h b/drivers/staging/comedi/comedidev.h index 616e9b08c026..77be191988ca 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 00194a5092cf..82ac84504589 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 |