Hello friend.
How are you, I'm Sgt.Kayla Manthey a US army serving in Iraq/Syria, i
want to make friends with you, please write back direct to my email
address (sgt.kayla03(a)gmail.com) to enable me to tell you more about my
self. I expect to receive your response direct to my email address
because i have something very important and private to share
with you.
Thanks
Sgt Kayla Manthey
From: Sai Krishna Potthuri <lakshmi.sai.krishna.potthuri(a)xilinx.com>
[ Upstream commit 21b511ddee09a78909035ec47a6a594349fe3296 ]
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.
Signed-off-by: Sai Krishna Potthuri <lakshmi.sai.krishna.potthuri(a)xilinx.com>
Signed-off-by: Amit Kumar Mahapatra <amit.kumar-mahapatra(a)xilinx.com>
Link: https://lore.kernel.org/r/20220606062525.18447-1-amit.kumar-mahapatra@xilin…
Signed-off-by: Mark Brown <broonie(a)kernel.org>
Signed-off-by: Sasha Levin <sashal(a)kernel.org>
---
drivers/spi/spi-cadence.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/spi/spi-cadence.c b/drivers/spi/spi-cadence.c
index e383c6368915..6d294a1fa5e5 100644
--- a/drivers/spi/spi-cadence.c
+++ b/drivers/spi/spi-cadence.c
@@ -72,6 +72,7 @@
#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
@@ -444,15 +445,20 @@ 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;
}
--
2.35.1
Greetings, I am Kayla Manthey, I'm contacting you because I have
something very important to share with you. Write back to enable me to
tell you more about myself. God bless you.
Best regard,
Sgt.Kayla Manthey