6.1-stable review patch. If anyone has any objections, please let me know.
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From: Bogdan-Gabriel Roman bogdan-gabriel.roman@nxp.com
[ Upstream commit 8a30a6d35a11ff5ccdede7d6740765685385a917 ]
The XSPI mode implementation in this driver still uses the EOQ flag to signal the last word in a transmission and deassert the PCS signal. However, at speeds lower than ~200kHZ, the PCS signal seems to remain asserted even when SR[EOQF] = 1 indicates the end of a transmission. This is a problem for target devices which require the deassertation of the PCS signal between transfers.
Hence, this commit 'forces' the deassertation of the PCS by stopping the module through MCR[HALT] after completing a new transfer. According to the reference manual, the module stops or transitions from the Running state to the Stopped state after the current frame, when any one of the following conditions exist: - The value of SR[EOQF] = 1. - The chip is in Debug mode and the value of MCR[FRZ] = 1. - The value of MCR[HALT] = 1.
This shouldn't be done if the last transfer in the message has cs_change set.
Fixes: ea93ed4c181b ("spi: spi-fsl-dspi: Use EOQ for last word in buffer even for XSPI mode") Signed-off-by: Bogdan-Gabriel Roman bogdan-gabriel.roman@nxp.com Signed-off-by: Larisa Grigore larisa.grigore@nxp.com Signed-off-by: James Clark james.clark@linaro.org Link: https://patch.msgid.link/20250522-james-nxp-spi-v2-2-bea884630cfb@linaro.org Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/spi/spi-fsl-dspi.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+)
diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c index 3f9609edac944..93cdc52f0fb06 100644 --- a/drivers/spi/spi-fsl-dspi.c +++ b/drivers/spi/spi-fsl-dspi.c @@ -61,6 +61,7 @@ #define SPI_SR_TFIWF BIT(18) #define SPI_SR_RFDF BIT(17) #define SPI_SR_CMDFFF BIT(16) +#define SPI_SR_TXRXS BIT(30) #define SPI_SR_CLEAR (SPI_SR_TCFQF | \ SPI_SR_TFUF | SPI_SR_TFFF | \ SPI_SR_CMDTCF | SPI_SR_SPEF | \ @@ -907,9 +908,20 @@ static int dspi_transfer_one_message(struct spi_controller *ctlr, struct spi_device *spi = message->spi; struct spi_transfer *transfer; int status = 0; + u32 val = 0; + bool cs_change = false;
message->actual_length = 0;
+ /* Put DSPI in running mode if halted. */ + regmap_read(dspi->regmap, SPI_MCR, &val); + if (val & SPI_MCR_HALT) { + regmap_update_bits(dspi->regmap, SPI_MCR, SPI_MCR_HALT, 0); + while (regmap_read(dspi->regmap, SPI_SR, &val) >= 0 && + !(val & SPI_SR_TXRXS)) + ; + } + list_for_each_entry(transfer, &message->transfers, transfer_list) { dspi->cur_transfer = transfer; dspi->cur_msg = message; @@ -934,6 +946,7 @@ static int dspi_transfer_one_message(struct spi_controller *ctlr, dspi->tx_cmd |= SPI_PUSHR_CMD_CONT; }
+ cs_change = transfer->cs_change; dspi->tx = transfer->tx_buf; dspi->rx = transfer->rx_buf; dspi->len = transfer->len; @@ -966,6 +979,15 @@ static int dspi_transfer_one_message(struct spi_controller *ctlr, spi_transfer_delay_exec(transfer); }
+ if (status || !cs_change) { + /* Put DSPI in stop mode */ + regmap_update_bits(dspi->regmap, SPI_MCR, + SPI_MCR_HALT, SPI_MCR_HALT); + while (regmap_read(dspi->regmap, SPI_SR, &val) >= 0 && + val & SPI_SR_TXRXS) + ; + } + message->status = status; spi_finalize_current_message(ctlr);
@@ -1206,6 +1228,8 @@ static int dspi_init(struct fsl_dspi *dspi) if (!spi_controller_is_slave(dspi->ctlr)) mcr |= SPI_MCR_MASTER;
+ mcr |= SPI_MCR_HALT; + regmap_write(dspi->regmap, SPI_MCR, mcr); regmap_write(dspi->regmap, SPI_SR, SPI_SR_CLEAR);