From bcb3a1676b87effbdeffe8da5c44f63433d158d9 Mon Sep 17 00:00:00 2001 From: Scott Valentine Date: Wed, 11 Nov 2009 14:26:49 -0800 Subject: [PATCH] rtc: v3020: fix v3020_mmio_read_bit() 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 Cc: Paul Gortmaker Cc: Raphael Assenat Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/rtc/rtc-v3020.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/rtc/rtc-v3020.c b/drivers/rtc/rtc-v3020.c index ad16405..423cd5a 100644 --- a/drivers/rtc/rtc-v3020.c +++ b/drivers/rtc/rtc-v3020.c @@ -96,7 +96,7 @@ static void v3020_mmio_write_bit(struct v3020 *chip, unsigned char bit) 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 = { -- 1.8.2.3