From 6820e812dafb4258bc14692f686eec5bde6fba86 Mon Sep 17 00:00:00 2001 From: Tudor Ambarus Date: Wed, 16 Dec 2020 11:23:21 +0200 Subject: spi: Fix the clamping of spi->max_speed_hz If spi->controller->max_speed_hz is zero, a non-zero spi->max_speed_hz will be overwritten by zero. Make sure spi->controller->max_speed_hz is not zero when clamping spi->max_speed_hz. Put the spi->controller->max_speed_hz non-zero check higher in the if, so that we avoid a superfluous init to zero when both spi->max_speed_hz and spi->controller->max_speed_hz are zero. Fixes: 9326e4f1e5dd ("spi: Limit the spi device max speed to controller's max speed") Reported-by: Geert Uytterhoeven Suggested-by: Geert Uytterhoeven Signed-off-by: Tudor Ambarus Tested-by: Geert Uytterhoeven Link: https://lore.kernel.org/r/20201216092321.413262-1-tudor.ambarus@microchip.com Signed-off-by: Mark Brown --- drivers/spi/spi.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'drivers/spi/spi.c') diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 51d7c004fbab..f59bf5094adb 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -3378,8 +3378,9 @@ int spi_setup(struct spi_device *spi) if (status) return status; - if (!spi->max_speed_hz || - spi->max_speed_hz > spi->controller->max_speed_hz) + if (spi->controller->max_speed_hz && + (!spi->max_speed_hz || + spi->max_speed_hz > spi->controller->max_speed_hz)) spi->max_speed_hz = spi->controller->max_speed_hz; mutex_lock(&spi->controller->io_mutex); -- cgit v1.2.3 From 6170d077bf92c5b3dfbe1021688d3c0404f7c9e9 Mon Sep 17 00:00:00 2001 From: Xu Yilun Date: Mon, 4 Jan 2021 09:29:09 +0800 Subject: spi: fix the divide by 0 error when calculating xfer waiting time The xfer waiting time is the result of xfer->len / xfer->speed_hz. This patch makes the assumption of 100khz xfer speed if the xfer->speed_hz is not assigned and stays 0. This avoids the divide by 0 issue and ensures a reasonable tolerant waiting time. Signed-off-by: Xu Yilun Link: https://lore.kernel.org/r/1609723749-3557-1-git-send-email-yilun.xu@intel.com Signed-off-by: Mark Brown --- drivers/spi/spi.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'drivers/spi/spi.c') diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index f59bf5094adb..720ab34784c1 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1108,6 +1108,7 @@ static int spi_transfer_wait(struct spi_controller *ctlr, { struct spi_statistics *statm = &ctlr->statistics; struct spi_statistics *stats = &msg->spi->statistics; + u32 speed_hz = xfer->speed_hz; unsigned long long ms; if (spi_controller_is_slave(ctlr)) { @@ -1116,8 +1117,11 @@ static int spi_transfer_wait(struct spi_controller *ctlr, return -EINTR; } } else { + if (!speed_hz) + speed_hz = 100000; + ms = 8LL * 1000LL * xfer->len; - do_div(ms, xfer->speed_hz); + do_div(ms, speed_hz); ms += ms + 200; /* some tolerance */ if (ms > UINT_MAX) -- cgit v1.2.3