Hi Nuno,
On 6/26/24 10:50, Nuno Sá wrote:
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 :)
Yes, this is a good compromise. Such helpers are more user-friendly for
the consumer. As long as I have to push a v3, I might take the
opportunity to add this.
BRs
Olivier
- Nuno Sá
