spi: flags 'SPI_CONTROLLER_MUST_RX' and 'SPI_CONTROLLER_MUST_TX' can't be...

spi: flags 'SPI_CONTROLLER_MUST_RX' and 'SPI_CONTROLLER_MUST_TX' can't be coexit with 'SPI_3WIRE' mode

since chip spi driver need get the transfer direction by 'tx_buf' and
'rx_buf' of 'struct spi_transfer' in 'SPI_3WIRE' mode.

so, we need bypass 'SPI_CONTROLLER_MUST_RX' and 'SPI_CONTROLLER_MUST_TX'
feature in 'SPI_3WIRE' mode
Signed-off-by: dillon min <dillon.minfei@gmail.com>
Link: https://lore.kernel.org/r/1590378348-8115-9-git-send-email-dillon.minfei@gmail.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi.c

@@ -1023,7 +1023,8 @@ static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
 	void *tmp;
 	unsigned int max_tx, max_rx;
 
-	if (ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX)) {
+	if ((ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX))
+		&& !(msg->spi->mode & SPI_3WIRE)) {
 		max_tx = 0;
 		max_rx = 0;