From: Doug Anderson <dianders@chromium.org>
Date: Wed, 3 Sep 2014 20:44:25 +0000 (-0700)
Subject: spi/rockchip: Fix the wait_for_idle() timeout
X-Git-Tag: v3.17-rc6~18^2^6~2
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=64bc0110f1ec905b1676b5ef60c1cc5b1799e1b6;p=karo-tx-linux.git

spi/rockchip: Fix the wait_for_idle() timeout

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>
---

diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c
index c0743604b906..2a31bc2d3fd3 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");
 }