From: Brad Bishop bradleyb@fuzziesquirrel.com
[ Upstream commit 0b546bbe9474ff23e6843916ad6d567f703b2396 ]
Use a clock divider tuned to a 200MHz FSI bus frequency (the maximum). 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. With FSI frequencies slower than 200MHz, the SPI clock will simply run slower, but safely.
Signed-off-by: Brad Bishop bradleyb@fuzziesquirrel.com Signed-off-by: Eddie James eajames@linux.ibm.com Signed-off-by: Joel Stanley joel@jms.id.au Link: https://lore.kernel.org/r/20200909222857.28653-3-eajames@linux.ibm.com Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 ef5e0826a53c3..a702e9d7d68c0 100644 --- a/drivers/spi/spi-fsi.c +++ b/drivers/spi/spi-fsi.c @@ -403,7 +403,7 @@ 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 {