During an SPI read operation, even if the xspi->txbuf passed to the
cdns_spi_writerinterface is empty, it is still necessary to call
cdns_spi_write(xspi, CDNS_SPI_TXD, txw); otherwise, the read operation
will fail to obtain data correctly due to a lack of clocks.

Fixes: 4e00135b2dd1 ("spi: spi-cadence: supports transmission with bits_per_word of 16 and 32")
Reported-by: Rodrigo Alencar <455.rodrigo.alencar@gmail.com>
Closes: https://lore.kernel.org/all/lbijvnnwsnddonmm5pveqzap6iibxhl4maneq43x4j6w64dev6@u75qhm5cwiob/
Signed-off-by: Jun Guo <jun.guo@cixtech.com>
---
 drivers/spi/spi-cadence.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/spi/spi-cadence.c b/drivers/spi/spi-cadence.c
index 47054da630d0..41b5b58cbfac 100644
--- a/drivers/spi/spi-cadence.c
+++ b/drivers/spi/spi-cadence.c
@@ -729,6 +729,7 @@ static int cdns_spi_probe(struct platform_device *pdev)
 	ctlr->unprepare_transfer_hardware = cdns_unprepare_transfer_hardware;
 	ctlr->mode_bits = SPI_CPOL | SPI_CPHA;
 	ctlr->bits_per_word_mask = SPI_BPW_MASK(8);
+	ctlr->flags = SPI_CONTROLLER_MUST_TX;
 
 	if (of_device_is_compatible(pdev->dev.of_node, "cix,sky1-spi-r1p6"))
 		ctlr->bits_per_word_mask |= SPI_BPW_MASK(16) | SPI_BPW_MASK(32);
-- 
2.34.1

On Thu, 15 Jan 2026 17:19:24 +0800, Jun Guo wrote:
> During an SPI read operation, even if the xspi->txbuf passed to the
> cdns_spi_writerinterface is empty, it is still necessary to call
> cdns_spi_write(xspi, CDNS_SPI_TXD, txw); otherwise, the read operation
> will fail to obtain data correctly due to a lack of clocks.
> 
> 

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next

Thanks!

[1/1] spi: spi-cadence: enable SPI_CONTROLLER_MUST_TX
      commit: f6b625639e39bc384a7bddbf134a698d40258b3b

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark