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 drivers/iio/buffer/hw-consumer.c

struct iio_hw_consumer — Hardware consumer structure
iio_hw_consumer_alloc() — Allocate IIO hardware consumer
iio_hw_consumer_free() — Free IIO hardware consumer
iio_hw_consumer_enable() — Enable IIO hardware consumer
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¶

struct iio_hw_consumer * iio_hw_consumer_alloc(struct device * dev)¶: Allocate IIO hardware consumer

Parameters

struct device * dev: Pointer to consumer device.

Description

Returns a valid iio_hw_consumer on success or a ERR_PTR() on failure.

void iio_hw_consumer_free(struct iio_hw_consumer * hwc)¶: Free IIO hardware consumer

Parameters

struct iio_hw_consumer * hwc: hw consumer to free.

struct iio_hw_consumer * devm_iio_hw_consumer_alloc(struct device * dev)¶: Resource-managed iio_hw_consumer_alloc()

Parameters

struct device * dev: Pointer to consumer device.

Description

Managed iio_hw_consumer_alloc. iio_hw_consumer allocated with this function is automatically freed on driver detach.

If an iio_hw_consumer allocated with this function needs to be freed separately, devm_iio_hw_consumer_free() must be used.

returns pointer to allocated iio_hw_consumer on success, NULL on failure.

void devm_iio_hw_consumer_free(struct device * dev, struct iio_hw_consumer * hwc)¶: Resource-managed iio_hw_consumer_free()

Parameters

struct device * dev: Pointer to consumer device.
struct iio_hw_consumer * hwc: iio_hw_consumer to free.

Description

Free iio_hw_consumer allocated with devm_iio_hw_consumer_alloc().

int iio_hw_consumer_enable(struct iio_hw_consumer * hwc)¶: Enable IIO hardware consumer

Parameters

struct iio_hw_consumer * hwc: iio_hw_consumer to enable.

Description

Returns 0 on success.

void iio_hw_consumer_disable(struct iio_hw_consumer * hwc)¶: Disable IIO hardware consumer

Parameters

struct iio_hw_consumer * hwc: iio_hw_consumer to disable.