spi: spi-geni-qcom: Select FIFO mode for chip select

Spi geni driver switches between FIFO and DMA modes based on xfer length.
FIFO mode relies on M_CMD_DONE_EN interrupt for completion while DMA mode
relies on XX_DMA_DONE.
During dynamic switching, if FIFO mode is chosen, FIFO related interrupts
are enabled and DMA related interrupts are disabled. And viceversa.
Chip select shares M_CMD_DONE_EN interrupt with FIFO to check completion.
Now, if a chip select operation is preceded by a DMA xfer, M_CMD_DONE_EN
interrupt would have been disabled and hence it will never receive one
resulting in timeout.

For chip select, in addition to setting the xfer mode to FIFO,
select_mode() to FIFO so that required interrupts are enabled.

Fixes: e5f0dfa ("spi: spi-geni-qcom: Add support for SE DMA mode")
Suggested-by: Praveen Talari <[email protected]
Signed-off-by: Vijaya Krishna Nivarthi <[email protected]
Reviewed-by: Douglas Anderson <[email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mark Brown <[email protected]

Author: Vijaya Krishna Nivarthi

drivers/spi/spi-geni-qcom.c

@@ -294,6 +294,8 @@ static void spi_geni_set_cs(struct spi_device *slv, bool set_flag)
 	mas->cs_flag = set_flag;
 	/* set xfer_mode to FIFO to complete cs_done in isr */
 	mas->cur_xfer_mode = GENI_SE_FIFO;
+	geni_se_select_mode(se, mas->cur_xfer_mode);
+
 	reinit_completion(&mas->cs_done);
 	if (set_flag)
 		geni_se_setup_m_cmd(se, SPI_CS_ASSERT, 0);