Some of the SPI controllers have a special set of format registers that defines how the transfer initiated to the FIFO by means of I/O protocol lines.
Each mode of transfer from slave would be required to configure the I/O protocol lines so-that the master would identify how many number I/O protocol lines were used and alter the protocol bits on the controller.
To address this issue (on these kinds of SPI controllers) this series is trying to send the I/O protocol lines being used on particular transfers.
patch 1: Transfer the opcode alone
patch 2: Add SPI I/O protocol lines via spi->proto
patch 3: Use spi->proto on SiFive SPI controller
Any inputs? Jagan.
Jagan Teki (3): spi: spi-mem: Xfer opcode alone for non spi-mem spi: Support SPI I/O protocol lines spi: sifive: Fix format register proto field
drivers/spi/spi-mem.c | 68 +++++++++++++++++++++++++--------------- drivers/spi/spi-sifive.c | 11 +++++-- drivers/spi/spi-uclass.c | 7 +++++ include/spi.h | 9 ++++++ 4 files changed, 67 insertions(+), 28 deletions(-)