lcd_spi_pre_trans_cb() function

Send a polling transaction, wait for it to complete, and return the result This function is the equivalent of calling spi_device_polling_start() followed by spi_device_polling_end(). Do not use this when there is still a transaction that hasn't been finalized.

Send a SPI transaction, wait for it to complete, and return the result This function is the equivalent of calling spi_device_queue_trans() followed by spi_device_get_trans_result(). Do not use this when there is still a transaction separately queued (started) from spi_device_queue_trans() or polling_start/transmit that hasn't been finalized.

Get the result of a SPI transaction queued earlier by ``spi_device_queue_trans``. This routine will wait until a transaction to the given device successfully completed. It will then return the description of the completed transaction so software can inspect the result and e.g. free the memory or reuse the buffers.

Queue a SPI transaction for interrupt transaction execution. Get the result by ``spi_device_get_trans_result``.

Immediately start a polling transaction.