[PATCH v4 01/10] iio: backend: add support for filter config

[Antoniu Miclaus <antoniu.miclaus@analog.com>]

Add backend support for digital filter type selection.

This setting can be adjusted within the IP cores interfacing devices.

The IP core can be configured based on the state of the actual
digital filter configuration of the part.

Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
---
no changes in v4.
 drivers/iio/industrialio-backend.c | 18 ++++++++++++++++++
 include/linux/iio/backend.h        | 13 +++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/drivers/iio/industrialio-backend.c b/drivers/iio/industrialio-backend.c
index d4ad36f54090..038c9e1e2857 100644
--- a/drivers/iio/industrialio-backend.c
+++ b/drivers/iio/industrialio-backend.c
@@ -778,6 +778,24 @@ static int __devm_iio_backend_get(struct device *dev, struct iio_backend *back)
 	return 0;
 }
 
+/**
+ * iio_backend_filter_type_set - Set filter type
+ * @back: Backend device
+ * @type: Filter type.
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
+ */
+int iio_backend_filter_type_set(struct iio_backend *back,
+				enum iio_backend_filter_type type)
+{
+	if (type >= IIO_BACKEND_FILTER_TYPE_MAX)
+		return -EINVAL;
+
+	return iio_backend_op_call(back, filter_type_set, type);
+}
+EXPORT_SYMBOL_NS_GPL(iio_backend_filter_type_set, "IIO_BACKEND");
+
 /**
  * iio_backend_ddr_enable - Enable interface DDR (Double Data Rate) mode
  * @back: Backend device
diff --git a/include/linux/iio/backend.h b/include/linux/iio/backend.h
index e45b7dfbec35..5526800f5d4a 100644
--- a/include/linux/iio/backend.h
+++ b/include/linux/iio/backend.h
@@ -76,6 +76,14 @@ enum iio_backend_interface_type {
 	IIO_BACKEND_INTERFACE_MAX
 };
 
+enum iio_backend_filter_type {
+	IIO_BACKEND_FILTER_TYPE_DISABLED,
+	IIO_BACKEND_FILTER_TYPE_SINC1,
+	IIO_BACKEND_FILTER_TYPE_SINC5,
+	IIO_BACKEND_FILTER_TYPE_SINC5_PLUS_COMP,
+	IIO_BACKEND_FILTER_TYPE_MAX
+};
+
 /**
  * struct iio_backend_ops - operations structure for an iio_backend
  * @enable: Enable backend.
@@ -100,6 +108,7 @@ enum iio_backend_interface_type {
  * @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.
+ * @filter_type_set: Set filter type.
  * @ddr_enable: Enable interface DDR (Double Data Rate) mode.
  * @ddr_disable: Disable interface DDR (Double Data Rate) mode.
  * @data_stream_enable: Enable data stream.
@@ -150,6 +159,8 @@ struct iio_backend_ops {
 					 size_t len);
 	int (*debugfs_reg_access)(struct iio_backend *back, unsigned int reg,
 				  unsigned int writeval, unsigned int *readval);
+	int (*filter_type_set)(struct iio_backend *back,
+			       enum iio_backend_filter_type type);
 	int (*ddr_enable)(struct iio_backend *back);
 	int (*ddr_disable)(struct iio_backend *back);
 	int (*data_stream_enable)(struct iio_backend *back);
@@ -190,6 +201,8 @@ int iio_backend_data_sample_trigger(struct iio_backend *back,
 int devm_iio_backend_request_buffer(struct device *dev,
 				    struct iio_backend *back,
 				    struct iio_dev *indio_dev);
+int iio_backend_filter_type_set(struct iio_backend *back,
+				enum iio_backend_filter_type type);
 int iio_backend_ddr_enable(struct iio_backend *back);
 int iio_backend_ddr_disable(struct iio_backend *back);
 int iio_backend_data_stream_enable(struct iio_backend *back);
-- 
2.49.0