On Tue, 2024-06-25 at 17:07 +0200, Olivier Moysan wrote: > Add iio_backend_read_raw() service to support attributes read > from an IIO backend. > > Signed-off-by: Olivier Moysan <olivier.moysan@xxxxxxxxxxx> > Reviewed-by: Nuno Sa <nuno.sa@xxxxxxxxxx> > --- > drivers/iio/industrialio-backend.c | 21 +++++++++++++++++++++ > include/linux/iio/backend.h | 6 +++++- > 2 files changed, 26 insertions(+), 1 deletion(-) > > diff --git a/drivers/iio/industrialio-backend.c b/drivers/iio/industrialio- > backend.c > index 929aff4040ed..0e2653de1956 100644 > --- a/drivers/iio/industrialio-backend.c > +++ b/drivers/iio/industrialio-backend.c > @@ -357,6 +357,27 @@ int devm_iio_backend_request_buffer(struct device *dev, > } > EXPORT_SYMBOL_NS_GPL(devm_iio_backend_request_buffer, IIO_BACKEND); > > +/** > + * iio_backend_read_raw - Request a channel attribute from the IIO backend. > + * @back: Backend device > + * @chan: IIO channel reference > + * @val: First element of the returned value > + * @val2: Second element of the returned value > + * @mask: Specify value to retrieve > + * > + * This callback replicates the read_raw callback of the IIO framework, and > is intended to > + * request miscellaneous channel attributes from the backend device. > + * > + * RETURNS: > + * 0 on success, negative error number on failure. > + */ > +int iio_backend_read_raw(struct iio_backend *back, struct iio_chan_spec const > *chan, int *val, > + int *val2, long mask) > +{ > + return iio_backend_op_call(back, read_raw, chan, val, val2, mask); > +} > +EXPORT_SYMBOL_NS_GPL(iio_backend_read_raw, IIO_BACKEND); I actually got an idea when looking at this for my existential crisis between dedicated APIs and a catch all .read_raw() :). What we can do is just provide the .read_raw() or write_raw() ops to backends (so we minimize the number of ops) and then we build on top of them for providing more readable (depending on the case; some cases it does make sense to just call iio_backend_read_raw()) APIs to frontends. So in your case you could have in backend.h static inline int iio_backend_read_scale(...) { return iio_backend_read_raw(..., IIO_CHAN_INFO_SCALE); } Naturally no need for you to do this right now in your series. Just wanted to write it down before I go into other stuff and forget about this :) - Nuno Sá