| Date | Sun, 06 Dec 2009 16:00:09 -0800 | From | Greg KH <> | Subject | [033/119] rtc: v3020: fix v3020_mmio_read_bit() |
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2.6.31-stable review patch. If anyone has any objections, please let us know.
------------------ From: Scott Valentine <svalentine@concentris-systems.com>
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@towertech.it> Cc: Paul Gortmaker <p_gortmaker@yahoo.com> Cc: Raphael Assenat <raph@8d.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- 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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