diff options
| -rw-r--r-- | drivers/staging/comedi/comedi_buf.c | 27 | ||||
| -rw-r--r-- | drivers/staging/comedi/comedidev.h | 2 |
2 files changed, 29 insertions, 0 deletions
diff --git a/drivers/staging/comedi/comedi_buf.c b/drivers/staging/comedi/comedi_buf.c index c60a45ad12b9..88a7cae97811 100644 --- a/drivers/staging/comedi/comedi_buf.c +++ b/drivers/staging/comedi/comedi_buf.c @@ -575,3 +575,30 @@ unsigned int comedi_read_array_from_buffer(struct comedi_subdevice *s, return num_bytes; } EXPORT_SYMBOL_GPL(comedi_read_array_from_buffer); + +/** + * comedi_buf_read_samples - read sample data from comedi buffer + * @s: comedi_subdevice struct + * @data: destination + * @nsamples: maximum number of samples to read + * + * Reads up to nsamples from the comedi buffer associated with the subdevice, + * marks it as read and updates the acquisition scan progress. + * + * Returns the amount of data read in bytes. + */ +unsigned int comedi_buf_read_samples(struct comedi_subdevice *s, + void *data, unsigned int nsamples) +{ + unsigned int max_samples; + unsigned int nbytes; + + max_samples = s->async->prealloc_bufsz / bytes_per_sample(s); + if (nsamples > max_samples) + nsamples = max_samples; + + nbytes = nsamples * bytes_per_sample(s); + + return comedi_read_array_from_buffer(s, data, nbytes); +} +EXPORT_SYMBOL_GPL(comedi_buf_read_samples); diff --git a/drivers/staging/comedi/comedidev.h b/drivers/staging/comedi/comedidev.h index fb8ff84dab35..ba4084bd5ed8 100644 --- a/drivers/staging/comedi/comedidev.h +++ b/drivers/staging/comedi/comedidev.h @@ -453,6 +453,8 @@ unsigned int comedi_write_array_to_buffer(struct comedi_subdevice *s, unsigned int num_bytes); unsigned int comedi_read_array_from_buffer(struct comedi_subdevice *s, void *data, unsigned int num_bytes); +unsigned int comedi_buf_read_samples(struct comedi_subdevice *s, + void *data, unsigned int nsamples); /* drivers.c - general comedi driver functions */ |