| 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. |
