[PATCH 1/8] iio: backend: add API for interface tuning

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From: Nuno Sa <nuno.sa@xxxxxxxxxx>

This is in preparation for supporting interface tuning in one for the
devices using the axi-adc backend. The new added interfaces are all
needed for that calibration:

 * iio_backend_test_pattern_set();
 * iio_backend_chan_status();
 * iio_backend_iodelay_set();
 * iio_backend_data_sample_trigger().

Signed-off-by: Nuno Sa <nuno.sa@xxxxxxxxxx>
---
 drivers/iio/industrialio-backend.c | 86 ++++++++++++++++++++++++++++++++++++++
 include/linux/iio/backend.h        | 57 +++++++++++++++++++++----
 2 files changed, 136 insertions(+), 7 deletions(-)

diff --git a/drivers/iio/industrialio-backend.c b/drivers/iio/industrialio-backend.c
index 2fea2bbbe47fd..45eea3b725a35 100644
--- a/drivers/iio/industrialio-backend.c
+++ b/drivers/iio/industrialio-backend.c
@@ -186,6 +186,92 @@ int iio_backend_data_format_set(struct iio_backend *back, unsigned int chan,
 }
 EXPORT_SYMBOL_NS_GPL(iio_backend_data_format_set, IIO_BACKEND);
 
+/**
+ * iio_backend_test_pattern_set - Configure a test pattern
+ * @back:	Backend device
+ * @chan:	Channel number
+ * @pattern:
+ *
+ * Configure a test pattern on the backend. This is typically used for
+ * calibrating the timings on the data digital interface.
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
+ */
+int iio_backend_test_pattern_set(struct iio_backend *back,
+				 unsigned int chan,
+				 enum iio_backend_test_pattern pattern)
+{
+	if (pattern >= IIO_BACKEND_TEST_PATTERN_MAX)
+		return -EINVAL;
+
+	return iio_backend_op_call(back, test_pattern_set, chan, pattern);
+}
+EXPORT_SYMBOL_NS_GPL(iio_backend_test_pattern_set, IIO_BACKEND);
+
+/**
+ * iio_backend_chan_status - Get the channel status
+ * @back:	Backend device
+ * @chan:	Channel number
+ * @status:	Channel status
+ *
+ * Get the current state of the backend channel. Typically used to check if
+ * there were any errors sending/receiving data.
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
+ */
+int iio_backend_chan_status(struct iio_backend *back, unsigned int chan,
+			    struct iio_backend_chan_status *status)
+{
+	return iio_backend_op_call(back, chan_status, chan, status);
+}
+EXPORT_SYMBOL_NS_GPL(iio_backend_chan_status, IIO_BACKEND);
+
+/**
+ * iio_backend_iodelay_set - Set digital I/O delay
+ * @back:	Backend device
+ * @lane:	Lane number
+ * @tap:	Number of taps
+ *
+ * Controls delays on sending/receiving data. One usecase for this is to
+ * calibrate the data digital interface so we get the best results when
+ * transferring data. Note that @tap has no unit since the actual delay per tap
+ * is very backend specific. Hence, frontend devices typically should go through
+ * an array of @taps (the size of that array should typically match the size of
+ * calibration points on the frontend device) and call this API.
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
+ */
+int iio_backend_iodelay_set(struct iio_backend *back, unsigned int lane,
+			    unsigned int tap)
+{
+	return iio_backend_op_call(back, iodelay_set, lane, tap);
+}
+EXPORT_SYMBOL_NS_GPL(iio_backend_iodelay_set, IIO_BACKEND);
+
+/**
+ * iio_backend_data_sample_trigger - Control when to sample data
+ * @back:	Backend device
+ * @trigger:	Data trigger
+ *
+ * Mostly useful for input backends. Configures the backend for when to sample
+ * data (eg: rising vs falling edge).
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
+ */
+int iio_backend_data_sample_trigger(struct iio_backend *back,
+				    enum iio_backend_sample_trigger trigger)
+{
+	if (trigger >= IIO_BACKEND_SAMPLE_TRIGGER_MAX)
+		return -EINVAL;
+
+	return iio_backend_op_call(back, data_sample_trigger, trigger);
+}
+EXPORT_SYMBOL_NS_GPL(iio_backend_data_sample_trigger, IIO_BACKEND);
+
 static void iio_backend_free_buffer(void *arg)
 {
 	struct iio_backend_buffer_pair *pair = arg;
diff --git a/include/linux/iio/backend.h b/include/linux/iio/backend.h
index a6d79381866ec..ad793fe0d78c2 100644
--- a/include/linux/iio/backend.h
+++ b/include/linux/iio/backend.h
@@ -15,6 +15,19 @@ enum iio_backend_data_type {
 	IIO_BACKEND_DATA_TYPE_MAX
 };
 
+/* vendor specific from 32 */
+enum iio_backend_test_pattern {
+	/* modified prbs9 */
+	IIO_BACKEND_ADI_PRBS_9A = 32,
+	IIO_BACKEND_TEST_PATTERN_MAX
+};
+
+enum iio_backend_sample_trigger {
+	IIO_BACKEND_SAMPLE_TRIGGER_EDGE_FALLING,
+	IIO_BACKEND_SAMPLE_TRIGGER_EDGE_RISING,
+	IIO_BACKEND_SAMPLE_TRIGGER_MAX
+};
+
 /**
  * struct iio_backend_data_fmt - Backend data format
  * @type:		Data type.
@@ -28,15 +41,27 @@ struct iio_backend_data_fmt {
 	bool enable;
 };
 
+/**
+ * struct iio_backend_chan_status - Backend channel status
+ *  @errors:	Errors occurred when sending/receiving data.
+ */
+struct iio_backend_chan_status {
+	bool errors;
+};
+
 /**
  * struct iio_backend_ops - operations structure for an iio_backend
- * @enable:		Enable backend.
- * @disable:		Disable backend.
- * @chan_enable:	Enable one channel.
- * @chan_disable:	Disable one channel.
- * @data_format_set:	Configure the data format for a specific channel.
- * @request_buffer:	Request an IIO buffer.
- * @free_buffer:	Free an IIO buffer.
+ * @enable:			Enable backend.
+ * @disable:			Disable backend.
+ * @chan_enable:		Enable one channel.
+ * @chan_disable:		Disable one channel.
+ * @data_format_set:		Configure the data format for a specific channel.
+ * @test_pattern_set:		Configure a test pattern.
+ * @chan_status:		Get the channel status.
+ * @iodelay_set:		Set digital I/O delay.
+ * @data_sample_trigger:	Control when to sample data.
+ * @request_buffer:		Request an IIO buffer.
+ * @free_buffer:		Free an IIO buffer.
  **/
 struct iio_backend_ops {
 	int (*enable)(struct iio_backend *back);
@@ -45,6 +70,15 @@ struct iio_backend_ops {
 	int (*chan_disable)(struct iio_backend *back, unsigned int chan);
 	int (*data_format_set)(struct iio_backend *back, unsigned int chan,
 			       const struct iio_backend_data_fmt *data);
+	int (*test_pattern_set)(struct iio_backend *back,
+				unsigned int chan,
+				enum iio_backend_test_pattern pattern);
+	int (*chan_status)(struct iio_backend *back, unsigned int chan,
+			   struct iio_backend_chan_status *status);
+	int (*iodelay_set)(struct iio_backend *back, unsigned int chan,
+			   unsigned int tap);
+	int (*data_sample_trigger)(struct iio_backend *back,
+				   enum iio_backend_sample_trigger trigger);
 	struct iio_buffer *(*request_buffer)(struct iio_backend *back,
 					     struct iio_dev *indio_dev);
 	void (*free_buffer)(struct iio_backend *back,
@@ -56,6 +90,15 @@ int iio_backend_chan_disable(struct iio_backend *back, unsigned int chan);
 int devm_iio_backend_enable(struct device *dev, struct iio_backend *back);
 int iio_backend_data_format_set(struct iio_backend *back, unsigned int chan,
 				const struct iio_backend_data_fmt *data);
+int iio_backend_test_pattern_set(struct iio_backend *back,
+				 unsigned int chan,
+				 enum iio_backend_test_pattern pattern);
+int iio_backend_chan_status(struct iio_backend *back, unsigned int chan,
+			    struct iio_backend_chan_status *status);
+int iio_backend_iodelay_set(struct iio_backend *back, unsigned int lane,
+			    unsigned int tap);
+int iio_backend_data_sample_trigger(struct iio_backend *back,
+				    enum iio_backend_sample_trigger trigger);
 int devm_iio_backend_request_buffer(struct device *dev,
 				    struct iio_backend *back,
 				    struct iio_dev *indio_dev);

-- 
2.44.0






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