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Diffstat (limited to 'drivers/staging/iio/Documentation/device.txt')
| -rw-r--r-- | drivers/staging/iio/Documentation/device.txt | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/drivers/staging/iio/Documentation/device.txt b/drivers/staging/iio/Documentation/device.txt new file mode 100644 index 000000000000..6916cd333350 --- /dev/null +++ b/drivers/staging/iio/Documentation/device.txt @@ -0,0 +1,49 @@ +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(); + +The 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. |