spi/rockchip: Fix the wait_for_idle() timeout
authorDoug Anderson <dianders@chromium.org>
Wed, 3 Sep 2014 20:44:25 +0000 (13:44 -0700)
committerMark Brown <broonie@kernel.org>
Thu, 4 Sep 2014 22:54:11 +0000 (23:54 +0100)
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@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
drivers/spi/spi-rockchip.c

index c074360..2a31bc2 100644 (file)
@@ -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");
 }