51bf00aef0
Spell-check wouln't catch these :) Signed-off-by: Amit Kucheria <amit.kucheria@verdurent.com> Acked-by: Jonathan Cameron <jic23@cam.ac.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
50 lines
1.5 KiB
Plaintext
50 lines
1.5 KiB
Plaintext
IIO Device drivers
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This is not intended to provide a comprehensive guide to writing an
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IIO device driver. For further information see the drivers within the
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subsystem.
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The crucial structure for device drivers in iio is iio_dev.
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First allocate one using:
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struct iio_dev *indio_dev = iio_allocate_device();
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Then fill in the following:
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indio_dev->dev.parent
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the struct device associated with the underlying hardware.
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indio_dev->num_interrupt_lines
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number of event triggering hardware lines the device has.
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indio_dev->event_attrs
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attributes used to enable / disable hardware events - note the
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attributes are embedded in iio_event_attr structures with an
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associated iio_event_handler which may or may note be shared.
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If num_interrupt_lines = 0, then no need to fill this in.
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indio_dev->attrs
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general attributes such as polled access to device channels.
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indio_dev->dev_data
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private device specific data.
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indio_dev->driver_module
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typically set to THIS_MODULE. Used to specify ownership of some
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iio created resources.
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indio_dev->modes
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whether direct access and / or ring buffer access is supported.
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Once these are set up, a call to iio_device_register(indio_dev),
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will register the device with the iio core.
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Worth noting here is that, if a ring buffer is to be used, it can be
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allocated prior to registering the device with the iio-core, but must
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be registered afterwards (otherwise the whole parentage of devices
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gets confused)
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On remove, iio_device_unregister(indio_dev) will remove the device from
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the core, and iio_free_device will clean up.
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