* @unprepare_message: undo any work done by prepare_message().
* @slave_abort: abort the ongoing transfer request on an SPI slave controller
* @cs_gpiods: Array of GPIO descs to use as chip select lines; one per CS
* @unprepare_message: undo any work done by prepare_message().
* @slave_abort: abort the ongoing transfer request on an SPI slave controller
* @cs_gpiods: Array of GPIO descs to use as chip select lines; one per CS