Dear Linux FPGA Maintainers, I did not found a way to use the struct spi_transfer to manage the chip select the way this fpga programming requires. Since the chip select is managed by this driver alone, it may interfere with the communication with other devices on the bus, which I tried to make clear in the documentation. Patch 1: - improved kconfig help: added warning on spi interference - fixed: efinix_spi_probe() warn: passing zero to 'PTR_ERR' - improved function naming: efinix_spi_*() - fixed: fpga_manager_ops.write could be called multiple times during one time reprogramming [attached: v3-0001-fpga-Add-Efinix-Trion-Titanium-serial-SPI-program.patch] Patch 2: - added warning on spi interference - removed unused label on example [attached: v3-0003-dt-bindings-fpga-Add-Efinix-serial-SPI-programmin.patch] Patch 3: - no changes [attached: v3-0003-dt-bindings-vendor-prefix-Add-prefix-for-Efinix-I.patch] Signed-off-by: Ian Dannapel <iansdannapel@xxxxxxxxx>