Putting it all together

The steps needed to write SPI client drivers are as follows:

1. Declare device IDs supported by the driver. You can do that using spi_device_id. If the DT is supported, use of_device_id too. You can make an exclusive use of the DT.
2. Call MODULE_DEVICE_TABLE(spi, my_id_table); in order to expose the driver along with its SPI device table IDs to userspace. If the DT is supported, you must call MODULE_DEVICE_TABLE(of, your_of_match_table); in order to expose OF (device tree) related module aliases to user space. The preceding calls to MODULE_DEVICE_TABLE will export informations that will be collected by depmod to update the modules.alias file, thus allowing the driver to be automatically found and loaded if it is build as module.
3. Write probe and remove functions according to their respective prototypes. The probe function must identify your device, configure it, define per-device (private) data, configure the bus if needed (SPI mode and so on) using the spi_setup function...