spi: rzv2h-rspi: set MUST_RX/MUST_TX

In preparation for implementing DMA support, set MUST_RX and MUST_TX
flags on the controller so that we always receive non-NULL buffers.

The PIO mode already handles this manually by checking if rx_buf/tx_buf
are set on the transfer, and doing a dummy read/write if not.

DMA will not be able to implement this special handling, and although
the SPI controller advertises support for transmit-only or receive-only
transfers via SPCR's register TXMD bitfield, it does not seem to work.

Remove the special handling for PIO and let the SPI controller core
handle it.

Signed-off-by: Cosmin Tanislav <cosmin-gabriel.tanislav.xa@renesas.com>
Link: https://patch.msgid.link/20251201134229.600817-7-cosmin-gabriel.tanislav.xa@renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi-rzv2h-rspi.c b/drivers/spi/spi-rzv2h-rspi.c
index 50fd7ddef58dee7cbeafeaf8566e97c17f6cb987..f0bbbd21c7633e6d107b9ec3351dfdf2bd7f59db 100644 (file)
--- a/drivers/spi/spi-rzv2h-rspi.c
+++ b/drivers/spi/spi-rzv2h-rspi.c
@@ -113,11 +113,7 @@ struct rzv2h_rspi_priv {
 static inline void rzv2h_rspi_tx_##type(struct rzv2h_rspi_priv *rspi,  \
                                        const void *txbuf,              \
                                        unsigned int index) {           \
-       type buf = 0;                                                   \
-                                                                       \
-       if (txbuf)                                                      \
-               buf = ((type *)txbuf)[index];                           \
-                                                                       \
+       type buf = ((type *)txbuf)[index];                              \
        func(buf, rspi->base + RSPI_SPDR);                              \
 }
 
@@ -126,9 +122,7 @@ static inline void rzv2h_rspi_rx_##type(struct rzv2h_rspi_priv *rspi,       \
                                        void *rxbuf,                    \
                                        unsigned int index) {           \
        type buf = func(rspi->base + RSPI_SPDR);                        \
-                                                                       \
-       if (rxbuf)                                                      \
-               ((type *)rxbuf)[index] = buf;                           \
+       ((type *)rxbuf)[index] = buf;                                   \
 }
 
 RZV2H_RSPI_TX(writel, u32)
@@ -596,6 +590,7 @@ static int rzv2h_rspi_probe(struct platform_device *pdev)
 
        controller->mode_bits = SPI_CPHA | SPI_CPOL | SPI_CS_HIGH |
                                SPI_LSB_FIRST | SPI_LOOP;
+       controller->flags = SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX;
        controller->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
        controller->prepare_message = rzv2h_rspi_prepare_message;
        controller->unprepare_message = rzv2h_rspi_unprepare_message;