Messages in this thread Patch in this message | | | From | Frieder Schrempf <> | Subject | [PATCH v2] spi: spi-imx: Fix spi_bus_clk if requested clock is higher than input clock | Date | Tue, 15 Nov 2022 17:26:53 +0100 |
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From: Frieder Schrempf <frieder.schrempf@kontron.de>
In case the requested bus clock is higher than the input clock, the correct dividers (pre = 0, post = 0) are returned from mx51_ecspi_clkdiv(), but *fres is left uninitialized and therefore contains an arbitrary value.
This causes trouble for the recently introduced PIO polling feature as the value in spi_imx->spi_bus_clk is used there to calculate for which transfers to enable PIO polling.
Fix this by setting *fres even if no clock dividers are in use.
This issue was observed on Kontron BL i.MX8MM with an SPI peripheral clock set to 50 MHz by default and a requested SPI bus clock of 80 MHz for the SPI NOR flash.
With the fix applied the debug message from mx51_ecspi_clkdiv() now prints the following:
spi_imx 30820000.spi: mx51_ecspi_clkdiv: fin: 50000000, fspi: 50000000, post: 0, pre: 0
Fixes: 07e759387788 ("spi: spi-imx: add PIO polling support") Cc: Marc Kleine-Budde <mkl@pengutronix.de> Cc: David Jander <david@protonic.nl> Cc: Fabio Estevam <festevam@gmail.com> Cc: Mark Brown <broonie@kernel.org> Cc: Marek Vasut <marex@denx.de> Cc: stable@vger.kernel.org Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de> ---
Changes for v2:
* Remove the reference and the Fixes tag for commit 6fd8b8503a0d as it is incorrect. --- drivers/spi/spi-imx.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c index 30d82cc7300b..468ce0a2b282 100644 --- a/drivers/spi/spi-imx.c +++ b/drivers/spi/spi-imx.c @@ -444,8 +444,7 @@ static unsigned int mx51_ecspi_clkdiv(struct spi_imx_data *spi_imx, unsigned int pre, post; unsigned int fin = spi_imx->spi_clk; - if (unlikely(fspi > fin)) - return 0; + fspi = min(fspi, fin); post = fls(fin) - fls(fspi); if (fin > fspi << post) -- 2.38.1
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