diff options
| author | Valentin Caron | 2023-09-06 15:27:35 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2023-10-06 14:56:55 +0200 |
| commit | 85ca138f922cd99370c56f884631f91cab661ac8 (patch) | |
| tree | 4b94669f93e7afac38063a47fcd88bf64b1299d0 /drivers | |
| parent | 84592ec591be7d6b03180c389d5a81dea09fabb5 (diff) | |
spi: stm32: add a delay before SPI disable
[ Upstream commit 6de8a70c84ee0586fdde4e671626b9caca6aed74 ]
As explained in errata sheet, in section "2.14.5 Truncation of SPI output
signals after EOT event":
On STM32MP1x, EOT interrupt can be thrown before the true end of
communication.
So we add a delay of a half period to wait the real end of the
transmission.
Link: https://www.st.com/resource/en/errata_sheet/es0539-stm32mp131x3x5x-device-errata-stmicroelectronics.pdf
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20230906132735.748174-1-valentin.caron@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/spi/spi-stm32.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c index def09cf0dc14..12241815510d 100644 --- a/drivers/spi/spi-stm32.c +++ b/drivers/spi/spi-stm32.c @@ -268,6 +268,7 @@ struct stm32_spi_cfg { * @fifo_size: size of the embedded fifo in bytes * @cur_midi: master inter-data idleness in ns * @cur_speed: speed configured in Hz + * @cur_half_period: time of a half bit in us * @cur_bpw: number of bits in a single SPI data frame * @cur_fthlv: fifo threshold level (data frames in a single data packet) * @cur_comm: SPI communication mode @@ -294,6 +295,7 @@ struct stm32_spi { unsigned int cur_midi; unsigned int cur_speed; + unsigned int cur_half_period; unsigned int cur_bpw; unsigned int cur_fthlv; unsigned int cur_comm; @@ -454,6 +456,8 @@ static int stm32_spi_prepare_mbr(struct stm32_spi *spi, u32 speed_hz, spi->cur_speed = spi->clk_rate / (1 << mbrdiv); + spi->cur_half_period = DIV_ROUND_CLOSEST(USEC_PER_SEC, 2 * spi->cur_speed); + return mbrdiv - 1; } @@ -695,6 +699,10 @@ static void stm32h7_spi_disable(struct stm32_spi *spi) return; } + /* Add a delay to make sure that transmission is ended. */ + if (spi->cur_half_period) + udelay(spi->cur_half_period); + if (spi->cur_usedma && spi->dma_tx) dmaengine_terminate_all(spi->dma_tx); if (spi->cur_usedma && spi->dma_rx) |