The CAIF TTY transport driver is a Line Discipline (ldisc) identified as N_CAIF. When this ldisc is opened from user space it will redirect the TTY's traffic into the CAIF stack.
The CAIF Link layer SPI Protocol driver for Slave SPI interface. This driver implements a platform driver to accommodate for a platform specific SPI device. A sample CAIF SPI Platform device is provided in Documentation/networking/caif/spi_porting.txt
Putting the next command and length in the start of the frame can help to synchronize to the next transfer in case of over or under-runs. This option also needs to be enabled on the modem.
The CAIF shared memory protocol driver for the STE UX5500 platform.