[PATCH v2] spi: fix the divide by 0 error when calculating xfer waiting time
flat view
STALE2111d
From: Xu Yilun <yilun.xu@intel.com>
Date: 2021-01-02 03:05:29
Also in:
lkml
Subsystem:
spi subsystem, the rest · Maintainers:
Mark Brown, Linus Torvalds
The xfer waiting time is the result of xfer->len / xfer->speed_hz. This
patch makes the assumption of 1khz 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 <yilun.xu@intel.com>
---
v2: use the normal conditional statement instead of the ternery operator
change the default xfer speed from 1khz to 100khz
---
drivers/spi/spi.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 51d7c00..aacae88 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)
--
2.7.4