[PATCH 2/4] iio: backend: add support for data source get

[Angelo Dureghello <adureghello@xxxxxxxxxxxx>]

From: Angelo Dureghello <adureghello@xxxxxxxxxxxx>

Add backend support for getting the data source used.

The ad3552r HDL implements an internal ramp generator, so adding the
getter to allow data source get/set by debugfs.

Signed-off-by: Angelo Dureghello <adureghello@xxxxxxxxxxxx>
---
 drivers/iio/industrialio-backend.c | 28 ++++++++++++++++++++++++++++
 include/linux/iio/backend.h        |  5 +++++
 2 files changed, 33 insertions(+)

diff --git a/drivers/iio/industrialio-backend.c b/drivers/iio/industrialio-backend.c
index a43c8d1bb3d0f4dda4277cac94b0ea9232c071e4..c1eb9ef9db08aec8437d0d00cf77914ad6611b72 100644
--- a/drivers/iio/industrialio-backend.c
+++ b/drivers/iio/industrialio-backend.c
@@ -380,6 +380,34 @@ int iio_backend_data_source_set(struct iio_backend *back, unsigned int chan,
 }
 EXPORT_SYMBOL_NS_GPL(iio_backend_data_source_set, "IIO_BACKEND");
 
+/**
+ * iio_backend_data_source_get - Get current data source
+ * @back: Backend device
+ * @chan: Channel number
+ * @data: Pointer to receive the current source value
+ *
+ * A given backend may have different sources to stream/sync data. This allows
+ * to know what source is in use.
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
+ */
+int iio_backend_data_source_get(struct iio_backend *back, unsigned int chan,
+				enum iio_backend_data_source *data)
+{
+	int ret;
+
+	ret = iio_backend_op_call(back, data_source_get, chan, data);
+	if (ret)
+		return ret;
+
+	if (*data >= IIO_BACKEND_DATA_SOURCE_MAX)
+		return -EINVAL;
+
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(iio_backend_data_source_get, "IIO_BACKEND");
+
 /**
  * iio_backend_set_sampling_freq - Set channel sampling rate
  * @back: Backend device
diff --git a/include/linux/iio/backend.h b/include/linux/iio/backend.h
index e45b7dfbec35c094942a3034fc6057a7960b9772..e59d909cb65924b4872cadd4b7e5e894c13c189f 100644
--- a/include/linux/iio/backend.h
+++ b/include/linux/iio/backend.h
@@ -84,6 +84,7 @@ enum iio_backend_interface_type {
  * @chan_disable: Disable one channel.
  * @data_format_set: Configure the data format for a specific channel.
  * @data_source_set: Configure the data source for a specific channel.
+ * @data_source_get: Data source getter for a specific channel.
  * @set_sample_rate: Configure the sampling rate for a specific channel.
  * @test_pattern_set: Configure a test pattern.
  * @chan_status: Get the channel status.
@@ -115,6 +116,8 @@ struct iio_backend_ops {
 			       const struct iio_backend_data_fmt *data);
 	int (*data_source_set)(struct iio_backend *back, unsigned int chan,
 			       enum iio_backend_data_source data);
+	int (*data_source_get)(struct iio_backend *back, unsigned int chan,
+			       enum iio_backend_data_source *data);
 	int (*set_sample_rate)(struct iio_backend *back, unsigned int chan,
 			       u64 sample_rate_hz);
 	int (*test_pattern_set)(struct iio_backend *back,
@@ -176,6 +179,8 @@ int iio_backend_data_format_set(struct iio_backend *back, unsigned int chan,
 				const struct iio_backend_data_fmt *data);
 int iio_backend_data_source_set(struct iio_backend *back, unsigned int chan,
 				enum iio_backend_data_source data);
+int iio_backend_data_source_get(struct iio_backend *back, unsigned int chan,
+				enum iio_backend_data_source *data);
 int iio_backend_set_sampling_freq(struct iio_backend *back, unsigned int chan,
 				  u64 sample_rate_hz);
 int iio_backend_test_pattern_set(struct iio_backend *back,

-- 
2.49.0