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[PATCH] MIPS: rb532: fix bit swapping in rb532_set_bit()

To: ralf@linux-mips.org
Subject: [PATCH] MIPS: rb532: fix bit swapping in rb532_set_bit()
From: Phil Sutter <n0-1@freewrt.org>
Date: Wed, 12 Nov 2008 00:09:30 +0100
Cc: linux-mips@linux-mips.org
In-reply-to: <20081103150542.GB13461@nuty>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <20081103150542.GB13461@nuty>
Sender: linux-mips-bounce@linux-mips.org
This is a simplified version of the original fix, thanks to Atsushi Nemoto for
the hint.

Greetings, Phil

---

The algorithm works unconditionally. If bitval is one, the first line is
a no op and the second line sets the bit at offset position. Vice versa,
if bitval is zero, the first line clears the bit at offset position and
the second line is a no op.

Signed-off-by: Phil Sutter <n0-1@freewrt.org>
---
 arch/mips/rb532/gpio.c |    6 ++----
 1 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/mips/rb532/gpio.c b/arch/mips/rb532/gpio.c
index 0e84c8a..e35cb75 100644
--- a/arch/mips/rb532/gpio.c
+++ b/arch/mips/rb532/gpio.c
@@ -119,13 +119,11 @@ static inline void rb532_set_bit(unsigned bitval,
        unsigned long flags;
        u32 val;
 
-       bitval = !!bitval;              /* map parameter to {0,1} */
-
        local_irq_save(flags);
 
        val = readl(ioaddr);
-       val &= ~( ~bitval << offset );   /* unset bit if bitval == 0 */
-       val |=  (  bitval << offset );   /* set bit if bitval == 1 */
+       val &= ~(!bitval << offset);   /* unset bit if bitval == 0 */
+       val |= (!!bitval << offset);   /* set bit if bitval == 1 */
        writel(val, ioaddr);
 
        local_irq_restore(flags);
-- 
1.5.6.4


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