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IIO Device drivers
This is not intended to provide a comprehensive guide to writing an
IIO device driver. For further information see the drivers within the
subsystem.
The crucial structure for device drivers in iio is iio_dev.
First allocate one using:
struct iio_dev *indio_dev = iio_allocate_device();
Then fill in the following:
indio_dev->dev.parent
the struct device associated with the underlying hardware.
indio_dev->num_interrupt_lines
number of event triggering hardware lines the device has.
indio_dev->event_attrs
attributes used to enable / disable hardware events - note the
attributes are embedded in iio_event_attr structures with an
associated iio_event_handler which may or may note be shared.
If num_interrupt_lines = 0, then no need to fill this in.
indio_dev->attrs
general attributes such as polled access to device channels.
indio_dev->dev_data
private device specific data.
indio_dev->driver_module
typically set to THIS_MODULE. Used to specify ownership of some
iio created resources.
indio_dev->modes
whether direct access and / or ring buffer access is supported.
Once these are set up, a call to iio_device_register(indio_dev),
will register the device with the iio core.
Worth noting here is that, if a ring buffer is to be used, it can be
allocated prior to registering the device with the iio-core, but must
be registered afterwards (otherwise the whole parentage of devices
gets confused)
On remove, iio_device_unregister(indio_dev) will remove the device from
the core, and iio_free_device will clean up.
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