docs: driver-api: add iio hw consumer section

This adds a section about the Hardware consumer
API of the IIO subsystem to the driver API
documentation.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/Documentation/driver-api/iio/hw-consumer.rst b/Documentation/driver-api/iio/hw-consumer.rst
new file mode 100644 (file)
index 0000000..8facce6
--- /dev/null
+++ b/Documentation/driver-api/iio/hw-consumer.rst
@@ -0,0 +1,51 @@
+===========
+HW consumer
+===========
+An IIO device can be directly connected to another device in hardware. in this
+case the buffers between IIO provider and IIO consumer are handled by hardware.
+The Industrial I/O HW consumer offers a way to bond these IIO devices without
+software buffer for data. The implementation can be found under
+:file:`drivers/iio/buffer/hw-consumer.c`
+
+
+* struct :c:type:`iio_hw_consumer` — Hardware consumer structure
+* :c:func:`iio_hw_consumer_alloc` — Allocate IIO hardware consumer
+* :c:func:`iio_hw_consumer_free` — Free IIO hardware consumer
+* :c:func:`iio_hw_consumer_enable` — Enable IIO hardware consumer
+* :c:func:`iio_hw_consumer_disable` — Disable IIO hardware consumer
+
+
+HW consumer setup
+=================
+
+As standard IIO device the implementation is based on IIO provider/consumer.
+A typical IIO HW consumer setup looks like this::
+
+       static struct iio_hw_consumer *hwc;
+
+       static const struct iio_info adc_info = {
+               .read_raw = adc_read_raw,
+       };
+
+       static int adc_read_raw(struct iio_dev *indio_dev,
+                               struct iio_chan_spec const *chan, int *val,
+                               int *val2, long mask)
+       {
+               ret = iio_hw_consumer_enable(hwc);
+
+               /* Acquire data */
+
+               ret = iio_hw_consumer_disable(hwc);
+       }
+
+       static int adc_probe(struct platform_device *pdev)
+       {
+               hwc = devm_iio_hw_consumer_alloc(&iio->dev);
+       }
+
+More details
+============
+.. kernel-doc:: include/linux/iio/hw-consumer.h
+.. kernel-doc:: drivers/iio/buffer/industrialio-hw-consumer.c
+   :export:
+

diff --git a/Documentation/driver-api/iio/index.rst b/Documentation/driver-api/iio/index.rst
index e5c3922..7fba341 100644 (file)
--- a/Documentation/driver-api/iio/index.rst
+++ b/Documentation/driver-api/iio/index.rst
@@ -15,3 +15,4 @@ Contents:
    buffers
    triggers
    triggered-buffers
+   hw-consumer