On Thursday, October 23, 2014 5:48 AM, Ian Abbott wrote:
> Introduce a few static inline helper functions:
>
> `comedi_bytes_per_sample(s)` is the same as the existing
> `bytes_per_sample(s)` and determines the size of a comedi sample in
> bytes. (`bytes_per_sample(s)` will be removed.)
>
> `comedi_sample_shift(s)` determines the log2 of the comedi sample size,
> so it can be used in bit-shift operations to multiply or divide by the
> sample size.
>
> `comedi_bytes_to_samples(s, nbytes)` converts a number of bytes to a
> number of samples (rounding down).
>
> `comedi_samples_to_bytes(s, nsamples)` converts a number of samples to a
> number of bytes.
>
> Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx>
> ---
> drivers/staging/comedi/comedidev.h | 63 +++++++++++++++++++++++++++++++++++---
> 1 file changed, 59 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/staging/comedi/comedidev.h b/drivers/staging/comedi/comedidev.h
> index 1b2bbd5..69cf6fe 100644
> --- a/drivers/staging/comedi/comedidev.h
> +++ b/drivers/staging/comedi/comedidev.h
> @@ -391,12 +391,67 @@ static inline unsigned int comedi_offset_munge(struct comedi_subdevice *s,
> return val ^ s->maxdata ^ (s->maxdata >> 1);
> }
>
> -static inline unsigned int bytes_per_sample(const struct comedi_subdevice *subd)
> +/**
> + * comedi_bytes_per_sample - determine subdevice sample size
> + * @s: comedi_subdevice struct
> + *
> + * The sample size will be 4 (sizeof int) or 2 (sizeof short) depending on
> + * whether the SDF_LSAMPL subdevice flag is set or not.
> + *
> + * Returns the subdevice sample size.
> + */
> +static inline unsigned int comedi_bytes_per_sample(struct comedi_subdevice *s)
> {
> - if (subd->subdev_flags & SDF_LSAMPL)
> - return sizeof(unsigned int);
> + return s->subdev_flags & SDF_LSAMPL ? sizeof(int) : sizeof(short);
The samples are really 'unsigned' types but I guess it doesn't matter here.
> +}
Reviewed-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
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