[PATCH linux dev-5.7 v2 2/7] spi: fsi: Fix clock running too fast

Eddie James eajames at linux.ibm.com
Fri Jul 31 08:03:25 AEST 2020


From: Brad Bishop <bradleyb at fuzziesquirrel.com>

Use a clock divider tuned to a 200MHz FSI clock.  Use of the previous
divider at 200MHz results in corrupt data from endpoint devices. Ideally
the clock divider would be calculated from the FSI clock, but that
would require some significant work on the FSI driver.

Signed-off-by: Brad Bishop <bradleyb at fuzziesquirrel.com>
Signed-off-by: Eddie James <eajames at linux.ibm.com>
---
 drivers/spi/spi-fsi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/spi/spi-fsi.c b/drivers/spi/spi-fsi.c
index 8f64af0140e0..559d0ff981f3 100644
--- a/drivers/spi/spi-fsi.c
+++ b/drivers/spi/spi-fsi.c
@@ -350,7 +350,7 @@ static int fsi_spi_transfer_init(struct fsi_spi *ctx)
 	u64 status = 0ULL;
 	u64 wanted_clock_cfg = SPI_FSI_CLOCK_CFG_ECC_DISABLE |
 		SPI_FSI_CLOCK_CFG_SCK_NO_DEL |
-		FIELD_PREP(SPI_FSI_CLOCK_CFG_SCK_DIV, 4);
+		FIELD_PREP(SPI_FSI_CLOCK_CFG_SCK_DIV, 19);
 
 	end = jiffies + msecs_to_jiffies(SPI_FSI_INIT_TIMEOUT_MS);
 	do {
-- 
2.24.0



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