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

Nuno Sa via B4 Relay
2024-04-19T15:36:52Z

From: Nuno Sa <nuno.sa@analog.com>

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@analog.com>
---
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