[PATCH 1/3] spi/rockchip: Fix the wait_for_idle() timeout

From: Doug Anderson
Date: Wed Sep 03 2014 - 16:44:48 EST


The wait_for_idle() could get unlucky and timeout too quickly.
Specifically, the old calculation was effectively:
timeout = jiffies + 1;
if (jiffies >= timeout) print warning;

>From the above it should be obvious that if jiffies ticks in just the
wrong place then we'll have an effective timeout of 0.

Fix this by effectively changing the above ">=" to a ">". That gives
us an extra jiffy to finish.

Signed-off-by: Doug Anderson <dianders@xxxxxxxxxxxx>
---
drivers/spi/spi-rockchip.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c
index cd0e08b0..84dbb86 100644
--- a/drivers/spi/spi-rockchip.c
+++ b/drivers/spi/spi-rockchip.c
@@ -220,7 +220,7 @@ static inline void wait_for_idle(struct rockchip_spi *rs)
do {
if (!(readl_relaxed(rs->regs + ROCKCHIP_SPI_SR) & SR_BUSY))
return;
- } while (time_before(jiffies, timeout));
+ } while (!time_after(jiffies, timeout));

dev_warn(rs->dev, "spi controller is in busy state!\n");
}
--
2.1.0.rc2.206.gedb03e5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/