[PATCH 2/2] spi: stm32: make SPI_MASTER_MUST_TX flags only specific to STM32F4

From: Alain Volmat
Date: Wed Jan 19 2022 - 04:33:41 EST


Commit 61367d0b8f5e ("spi: stm32: Add 'SPI_SIMPLEX_RX', 'SPI_3WIRE_RX' support for stm32f4")
allowed to properly communicate with the st-gyro-spi even when
there is no tx_buf provided by setting the flag SPI_MASTER_MUST_TX and
thus forcing a dummy TX buffer to work in Full Duplex.
This behavior should kept only for the STM32F4 and not for other
compatible since the STM32H7 do support SIMPLEX_RX and SIMPLEX_TX.
Add the flags variable within the struct stm32_spi_cfg so that flags
used at master registration time are compatible specific.

Fixes: 61367d0b8f5e ("spi: stm32: Add 'SPI_SIMPLEX_RX', 'SPI_3WIRE_RX' support for stm32f4")

Signed-off-by: Alain Volmat <alain.volmat@xxxxxxxxxxx>
---
drivers/spi/spi-stm32.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c
index b5ef2470cefe..7fc24505a72c 100644
--- a/drivers/spi/spi-stm32.c
+++ b/drivers/spi/spi-stm32.c
@@ -231,6 +231,7 @@ struct stm32_spi;
* @baud_rate_div_min: minimum baud rate divisor
* @baud_rate_div_max: maximum baud rate divisor
* @has_fifo: boolean to know if fifo is used for driver
+ * @flags: compatible specific SPI controller flags used at registration time
*/
struct stm32_spi_cfg {
const struct stm32_spi_regspec *regs;
@@ -251,6 +252,7 @@ struct stm32_spi_cfg {
unsigned int baud_rate_div_min;
unsigned int baud_rate_div_max;
bool has_fifo;
+ u16 flags;
};

/**
@@ -1720,6 +1722,7 @@ static const struct stm32_spi_cfg stm32f4_spi_cfg = {
.baud_rate_div_min = STM32F4_SPI_BR_DIV_MIN,
.baud_rate_div_max = STM32F4_SPI_BR_DIV_MAX,
.has_fifo = false,
+ .flags = SPI_MASTER_MUST_TX,
};

static const struct stm32_spi_cfg stm32h7_spi_cfg = {
@@ -1852,7 +1855,7 @@ static int stm32_spi_probe(struct platform_device *pdev)
master->prepare_message = stm32_spi_prepare_msg;
master->transfer_one = stm32_spi_transfer_one;
master->unprepare_message = stm32_spi_unprepare_msg;
- master->flags = SPI_MASTER_MUST_TX;
+ master->flags = spi->cfg->flags;

spi->dma_tx = dma_request_chan(spi->dev, "tx");
if (IS_ERR(spi->dma_tx)) {
--
2.25.1