From 020b700552021a50b64854ad6b8464e4c4808244 Mon Sep 17 00:00:00 2001 From: Brad Bishop Date: Wed, 9 Sep 2020 17:28:53 -0500 Subject: [PATCH] spi: fsi: Fix clock running too fast [ 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 Signed-off-by: Eddie James Signed-off-by: Joel Stanley Link: https://lore.kernel.org/r/20200909222857.28653-3-eajames@linux.ibm.com Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- 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 { -- 2.51.0