[PATCH v5 1/9] iio: add read scale and offset services to iio backend framework

[Olivier Moysan]

Add iio_backend_read_scale() and iio_backend_read_offset() services
to read channel scale and offset from an IIO backbend device.

Also add a read_raw callback which replicates the read_raw callback of
the IIO framework, and is intended to request miscellaneous channel
attributes from the backend device.
Both scale and offset helpers use this callback.

Signed-off-by: Olivier Moysan <olivier...@foss.st.com>
Reviewed-by: Nuno Sa <nun...@analog.com>
---
drivers/iio/industrialio-backend.c | 19 +++++++++++++++++++
include/linux/iio/backend.h | 24 +++++++++++++++++++++++-
2 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/industrialio-backend.c b/drivers/iio/industrialio-backend.c
index f9da635cdfea..72dc82a42d8f 100644
--- a/drivers/iio/industrialio-backend.c
+++ b/drivers/iio/industrialio-backend.c
@@ -361,6 +361,25 @@ int devm_iio_backend_request_buffer(struct device *dev,
}
EXPORT_SYMBOL_NS_GPL(devm_iio_backend_request_buffer, IIO_BACKEND);

+/**
+ * iio_backend_read_raw - Read a channel attribute from a backend device.
+ * @back: Backend device
+ * @chan: IIO channel reference
+ * @val: First returned value
+ * @val2: Second returned value
+ * @mask: Specify the attribute to return
+ *
+ * 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);
+
static struct iio_backend *iio_backend_from_indio_dev_parent(const struct device *dev)
{
struct iio_backend *back = ERR_PTR(-ENODEV), *iter;
diff --git a/include/linux/iio/backend.h b/include/linux/iio/backend.h
index 4e81931703ab..578e8f33d27b 100644
--- a/include/linux/iio/backend.h
+++ b/include/linux/iio/backend.h
@@ -3,6 +3,7 @@
#define _IIO_BACKEND_H_

#include <linux/types.h>
+#include <linux/iio/iio.h>

struct iio_chan_spec;
struct fwnode_handle;
@@ -81,6 +82,7 @@ enum iio_backend_sample_trigger {
* @extend_chan_spec: Extend an IIO channel.
* @ext_info_set: Extended info setter.
* @ext_info_get: Extended info getter.
+ * @read_raw: Read a channel attribute from a backend device
**/
struct iio_backend_ops {
int (*enable)(struct iio_backend *back);
@@ -113,6 +115,9 @@ struct iio_backend_ops {
const char *buf, size_t len);
int (*ext_info_get)(struct iio_backend *back, uintptr_t private,
const struct iio_chan_spec *chan, char *buf);
+ int (*read_raw)(struct iio_backend *back,
+ struct iio_chan_spec const *chan, int *val, int *val2,
+ long mask);
};

int iio_backend_chan_enable(struct iio_backend *back, unsigned int chan);
@@ -141,7 +146,9 @@ ssize_t iio_backend_ext_info_set(struct iio_dev *indio_dev, uintptr_t private,
const char *buf, size_t len);
ssize_t iio_backend_ext_info_get(struct iio_dev *indio_dev, uintptr_t private,
const struct iio_chan_spec *chan, char *buf);
-
+int iio_backend_read_raw(struct iio_backend *back,
+ struct iio_chan_spec const *chan, int *val, int *val2,
+ long mask);
int iio_backend_extend_chan_spec(struct iio_backend *back,
struct iio_chan_spec *chan);
void *iio_backend_get_priv(const struct iio_backend *conv);
@@ -153,4 +160,19 @@ __devm_iio_backend_get_from_fwnode_lookup(struct device *dev,
int devm_iio_backend_register(struct device *dev,
const struct iio_backend_ops *ops, void *priv);

+static inline int iio_backend_read_scale(struct iio_backend *back,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2)
+{
+ return iio_backend_read_raw(back, chan, val, val2, IIO_CHAN_INFO_SCALE);
+}
+
+static inline int iio_backend_read_offset(struct iio_backend *back,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2)
+{
+ return iio_backend_read_raw(back, chan, val, val2,
+ IIO_CHAN_INFO_OFFSET);
+}
+
#endif
--
2.25.1

[Olivier Moysan]

index 29c4cf0bd761..18b20426c25e 100644