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[PATCH v10 3/8] iio: backend: add API for oversampling

Antoniu Miclaus posted 8 patches 1 month ago
There is a newer version of this series
[PATCH v10 3/8] iio: backend: add API for oversampling
Posted by Antoniu Miclaus 1 month ago 
Add backend support for setting oversampling ratio.

Reviewed-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
---
no changes in v10.
 drivers/iio/industrialio-backend.c | 15 +++++++++++++++
 include/linux/iio/backend.h        |  5 +++++
 2 files changed, 20 insertions(+)

diff --git a/drivers/iio/industrialio-backend.c b/drivers/iio/industrialio-backend.c
index 2088afa7a55c..d4ad36f54090 100644
--- a/drivers/iio/industrialio-backend.c
+++ b/drivers/iio/industrialio-backend.c
@@ -681,6 +681,21 @@ int iio_backend_data_size_set(struct iio_backend *back, unsigned int size)
 }
 EXPORT_SYMBOL_NS_GPL(iio_backend_data_size_set, "IIO_BACKEND");
 
+/**
+ * iio_backend_oversampling_ratio_set - set the oversampling ratio
+ * @back: Backend device
+ * @ratio: The oversampling ratio - value 1 corresponds to no oversampling.
+ *
+ * Return:
+ * 0 on success, negative error number on failure.
+ */
+int iio_backend_oversampling_ratio_set(struct iio_backend *back,
+				       unsigned int ratio)
+{
+	return iio_backend_op_call(back, oversampling_ratio_set, ratio);
+}
+EXPORT_SYMBOL_NS_GPL(iio_backend_oversampling_ratio_set, "IIO_BACKEND");
+
 /**
  * iio_backend_extend_chan_spec - Extend an IIO channel
  * @back: Backend device
diff --git a/include/linux/iio/backend.h b/include/linux/iio/backend.h
index 9ae861a21472..e45b7dfbec35 100644
--- a/include/linux/iio/backend.h
+++ b/include/linux/iio/backend.h
@@ -96,6 +96,7 @@ enum iio_backend_interface_type {
  * @ext_info_get: Extended info getter.
  * @interface_type_get: Interface type.
  * @data_size_set: Data size.
+ * @oversampling_ratio_set: Set Oversampling ratio.
  * @read_raw: Read a channel attribute from a backend device
  * @debugfs_print_chan_status: Print channel status into a buffer.
  * @debugfs_reg_access: Read or write register value of backend.
@@ -139,6 +140,8 @@ struct iio_backend_ops {
 	int (*interface_type_get)(struct iio_backend *back,
 				  enum iio_backend_interface_type *type);
 	int (*data_size_set)(struct iio_backend *back, unsigned int size);
+	int (*oversampling_ratio_set)(struct iio_backend *back,
+				      unsigned int ratio);
 	int (*read_raw)(struct iio_backend *back,
 			struct iio_chan_spec const *chan, int *val, int *val2,
 			long mask);
@@ -200,6 +203,8 @@ ssize_t iio_backend_ext_info_get(struct iio_dev *indio_dev, uintptr_t private,
 int iio_backend_interface_type_get(struct iio_backend *back,
 				   enum iio_backend_interface_type *type);
 int iio_backend_data_size_set(struct iio_backend *back, unsigned int size);
+int iio_backend_oversampling_ratio_set(struct iio_backend *back,
+				       unsigned int ratio);
 int iio_backend_read_raw(struct iio_backend *back,
 			 struct iio_chan_spec const *chan, int *val, int *val2,
 			 long mask);
-- 
2.48.1
Re: [PATCH v10 3/8] iio: backend: add API for oversampling
Posted by Nuno Sá 1 month ago 
On Fri, 2025-01-17 at 15:06 +0200, Antoniu Miclaus wrote:
> Add backend support for setting oversampling ratio.
> 
> Reviewed-by: David Lechner <dlechner@baylibre.com>
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> ---
> no changes in v10.
>  drivers/iio/industrialio-backend.c | 15 +++++++++++++++
>  include/linux/iio/backend.h        |  5 +++++
>  2 files changed, 20 insertions(+)
> 
> diff --git a/drivers/iio/industrialio-backend.c b/drivers/iio/industrialio-
> backend.c
> index 2088afa7a55c..d4ad36f54090 100644
> --- a/drivers/iio/industrialio-backend.c
> +++ b/drivers/iio/industrialio-backend.c
> @@ -681,6 +681,21 @@ int iio_backend_data_size_set(struct iio_backend *back,
> unsigned int size)
>  }
>  EXPORT_SYMBOL_NS_GPL(iio_backend_data_size_set, "IIO_BACKEND");
>  
> +/**
> + * iio_backend_oversampling_ratio_set - set the oversampling ratio
> + * @back: Backend device
> + * @ratio: The oversampling ratio - value 1 corresponds to no oversampling.
> + *
> + * Return:
> + * 0 on success, negative error number on failure.
> + */
> +int iio_backend_oversampling_ratio_set(struct iio_backend *back,
> +				       unsigned int ratio)
> +{
> +	return iio_backend_op_call(back, oversampling_ratio_set, ratio);
> +}
> +EXPORT_SYMBOL_NS_GPL(iio_backend_oversampling_ratio_set, "IIO_BACKEND");
> +

Hmm, I'm very late to the party so don't bother in sending another revision
unless you have too. But if you do, I would prefer to have this through a
write_raw() interface. Meaning we would only have write_raw() as a backend op
and  then you could add this as a convenient inline helper built on top of
write_raw(). So this would be inline with what happens with read_raw(). Anyways,
we can clean it up afterwards since we already have a .set_sample_rate() op that
could use a similar approach.

- Nuno Sá
Re: [PATCH v10 3/8] iio: backend: add API for oversampling
Posted by Jonathan Cameron 1 month ago 
On Fri, 17 Jan 2025 16:17:13 +0000
Nuno Sá <noname.nuno@gmail.com> wrote:

> On Fri, 2025-01-17 at 15:06 +0200, Antoniu Miclaus wrote:
> > Add backend support for setting oversampling ratio.
> > 
> > Reviewed-by: David Lechner <dlechner@baylibre.com>
> > Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> > ---
> > no changes in v10.
> >  drivers/iio/industrialio-backend.c | 15 +++++++++++++++
> >  include/linux/iio/backend.h        |  5 +++++
> >  2 files changed, 20 insertions(+)
> > 
> > diff --git a/drivers/iio/industrialio-backend.c b/drivers/iio/industrialio-
> > backend.c
> > index 2088afa7a55c..d4ad36f54090 100644
> > --- a/drivers/iio/industrialio-backend.c
> > +++ b/drivers/iio/industrialio-backend.c
> > @@ -681,6 +681,21 @@ int iio_backend_data_size_set(struct iio_backend *back,
> > unsigned int size)
> >  }
> >  EXPORT_SYMBOL_NS_GPL(iio_backend_data_size_set, "IIO_BACKEND");
> >  
> > +/**
> > + * iio_backend_oversampling_ratio_set - set the oversampling ratio
> > + * @back: Backend device
> > + * @ratio: The oversampling ratio - value 1 corresponds to no oversampling.
> > + *
> > + * Return:
> > + * 0 on success, negative error number on failure.
> > + */
> > +int iio_backend_oversampling_ratio_set(struct iio_backend *back,
> > +				       unsigned int ratio)
> > +{
> > +	return iio_backend_op_call(back, oversampling_ratio_set, ratio);
> > +}
> > +EXPORT_SYMBOL_NS_GPL(iio_backend_oversampling_ratio_set, "IIO_BACKEND");
> > +  
> 
> Hmm, I'm very late to the party so don't bother in sending another revision
> unless you have too. But if you do, I would prefer to have this through a
> write_raw() interface. Meaning we would only have write_raw() as a backend op
> and  then you could add this as a convenient inline helper built on top of
> write_raw(). So this would be inline with what happens with read_raw(). Anyways,
> we can clean it up afterwards since we already have a .set_sample_rate() op that
> could use a similar approach.
I'm not against this, but just to mention that will run into the question of
whether to support the more complex value types.  I guess for now perhaps
pass in val, val2 and the write type and just reject anything that isn't
supported by a particular backend.

> 
> - Nuno Sá
> 
>

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