| Message ID | 20220606062525.18447-1-amit.kumar-mahapatra@xilinx.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 21b511ddee09a78909035ec47a6a594349fe3296 |
| Headers | show |
| Series | spi: spi-cadence: Fix SPI CS gets toggling sporadically | expand |
On Mon, 6 Jun 2022 11:55:25 +0530, Amit Kumar Mahapatra wrote: > From: Sai Krishna Potthuri <lakshmi.sai.krishna.potthuri@xilinx.com> > > As part of unprepare_transfer_hardware, SPI controller will be disabled > which will indirectly deassert the CS line. This will create a problem > in some of the devices where message will be transferred with > cs_change flag set(CS should not be deasserted). > As per SPI controller implementation, if SPI controller is disabled then > all output enables are inactive and all pins are set to input mode which > means CS will go to default state high(deassert). This leads to an issue > when core explicitly ask not to deassert the CS (cs_change = 1). This > patch fix the above issue by checking the Slave select status bits from > configuration register before disabling the SPI. > > [...] Applied to https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next Thanks! [1/1] spi: spi-cadence: Fix SPI CS gets toggling sporadically commit: 21b511ddee09a78909035ec47a6a594349fe3296 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
diff --git a/drivers/spi/spi-cadence.c b/drivers/spi/spi-cadence.c index b509eefe16a8..e832ae09e0cd 100644 --- a/drivers/spi/spi-cadence.c +++ b/drivers/spi/spi-cadence.c @@ -69,6 +69,7 @@ #define CDNS_SPI_BAUD_DIV_SHIFT 3 /* Baud rate divisor shift in CR */ #define CDNS_SPI_SS_SHIFT 10 /* Slave Select field shift in CR */ #define CDNS_SPI_SS0 0x1 /* Slave Select zero */ +#define CDNS_SPI_NOSS 0x3C /* No Slave select */ /* * SPI Interrupt Registers bit Masks @@ -449,15 +450,20 @@ static int cdns_prepare_transfer_hardware(struct spi_master *master) * @master: Pointer to the spi_master structure which provides * information about the controller. * - * This function disables the SPI master controller. + * This function disables the SPI master controller when no slave selected. * * Return: 0 always */ static int cdns_unprepare_transfer_hardware(struct spi_master *master) { struct cdns_spi *xspi = spi_master_get_devdata(master); + u32 ctrl_reg; - cdns_spi_write(xspi, CDNS_SPI_ER, CDNS_SPI_ER_DISABLE); + /* Disable the SPI if slave is deselected */ + ctrl_reg = cdns_spi_read(xspi, CDNS_SPI_CR); + ctrl_reg = (ctrl_reg & CDNS_SPI_CR_SSCTRL) >> CDNS_SPI_SS_SHIFT; + if (ctrl_reg == CDNS_SPI_NOSS) + cdns_spi_write(xspi, CDNS_SPI_ER, CDNS_SPI_ER_DISABLE); return 0; }