[PATCH v7 13/18] spi: cadence-quadspi: reprogram CS timing on every chip-select switch
From: Santhosh Kumar K <hidden>
Date: 2026-08-11 18:35:26
Also in:
linux-spi, lkml
Subsystem:
spi subsystem, the rest · Maintainers:
Mark Brown, Linus Torvalds
cqspi_configure() only reprogrammed per-device CS timing (CQSPI_REG_DELAY) and the non-PHY read-capture register when the clock frequency changed, not when the chip-select changed. In a multi-device setup where both devices operate at the same frequency, a CS switch leaves the previous device's timing parameters in hardware. Split the update condition: baud rate divisor is updated on clock change only (it is frequency-derived), but the per-device delay and read-capture registers are now updated on any CS or clock switch. Signed-off-by: Santhosh Kumar K <redacted> --- drivers/spi/spi-cadence-quadspi.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c
index 940cfb72b946..d4181b501d8d 100644
--- a/drivers/spi/spi-cadence-quadspi.c
+++ b/drivers/spi/spi-cadence-quadspi.c@@ -1602,10 +1602,19 @@ static void cqspi_configure(struct cqspi_flash_pdata *f_pdata, cqspi_chipselect(f_pdata); } - /* Setup baudrate divisor and delays */ + /* Update baudrate only on clock change. */ if (switch_ck) { cqspi->sclk = sclk; cqspi_config_baudrate_div(cqspi); + } + + /* + * Reprogram per-device CS timing and non-PHY read capture on any + * chip-select or clock switch. Without this, two devices at the same + * frequency would each see the other's timing parameters after a CS + * switch, since the lazy clock-only check would never trigger. + */ + if (switch_cs || switch_ck) { cqspi_delay(f_pdata); if (!cqspi->phy_tuning_active) cqspi_readdata_capture(cqspi, !cqspi->rclk_en, false,
--
2.34.1