[033/119] rtc: v3020: fix v3020_mmio_read_bit()

[Greg KH]

2.6.31-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Scott Valentine <svalentine@xxxxxxxxxxxxxxxxxxxxxx>

commit bcb3a1676b87effbdeffe8da5c44f63433d158d9 upstream.

v3020_mmio_read_bit() always returns 0 when left_shift > 7.

v3020_mmio_read_bit()'s return type is (unsigned char).  The code returns
a value masked by (1 << left_shift) that is casted to the return type.  If
left_shift is larger than 7, the cast will always result in a 0 return
value.  The problem was discovered with left_shift = 16, and the included
patch corrects the problem.

The bug was introduced in the last (Apr 3 2009) commit of the file, kernel
versions 2.6.30 and later.

Cc: Alessandro Zummo <a.zummo@xxxxxxxxxxxx>
Cc: Paul Gortmaker <p_gortmaker@xxxxxxxxx>
Cc: Raphael Assenat <raph@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/rtc/rtc-v3020.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/rtc/rtc-v3020.c
+++ b/drivers/rtc/rtc-v3020.c
@@ -96,7 +96,7 @@ static void v3020_mmio_write_bit(struct 
 
 static unsigned char v3020_mmio_read_bit(struct v3020 *chip)
 {
-	return readl(chip->ioaddress) & (1 << chip->leftshift);
+	return !!(readl(chip->ioaddress) & (1 << chip->leftshift));
 }
 
 static struct v3020_chip_ops v3020_mmio_ops = {


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