spi: limit reaches -1, tested 0

With a postfix decrement limit will reach -1 rather than 0, so the warning
will not be issued.

Also, add a cpu_relax() into the busy-wait loop.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: Mariusz Ceier <mceier@gmail.com>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/spi/spi_imx.c b/drivers/spi/spi_imx.c
index 0480d8bb19d32b7a6d81b2b43efafc2a7fe8defd..014af69fc1bbba62ac386a1f147c7e816af14a0b 100644 (file)
--- a/drivers/spi/spi_imx.c
+++ b/drivers/spi/spi_imx.c
@@ -779,7 +779,8 @@ static irqreturn_t interrupt_transfer(struct driver_data *drv_data)
 
                        /* Read trailing bytes */
                        limit = loops_per_jiffy << 1;
-                       while ((read(drv_data) == 0) && limit--);
+                       while ((read(drv_data) == 0) && --limit)
+                               cpu_relax();
 
                        if (limit == 0)
                                dev_err(&drv_data->pdev->dev,