[PATCH 1/1] clk-divider: fix is_power_of_two()

From: James Hogan
Date: Tue Jan 15 2013 - 05:28:07 EST


The macro is_power_of_two() in clk-divider.c was defined as !(i & ~i)
which is always true. Correct it to !(i & (i - 1)).

Also add brackets around the macro arguments in div_mask and
is_power_of_two, as well as around the is_power_of_two expression as a
whole to avoid any future operator precedence problems.

Signed-off-by: James Hogan <james.hogan@xxxxxxxxxx>
Cc: Mike Turquette <mturquette@xxxxxxxxxx>
---
I haven't tested this other than with a couple of compile time asserts.

drivers/clk/clk-divider.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
index a9204c6..13bca0c 100644
--- a/drivers/clk/clk-divider.c
+++ b/drivers/clk/clk-divider.c
@@ -29,8 +29,8 @@

#define to_clk_divider(_hw) container_of(_hw, struct clk_divider, hw)

-#define div_mask(d) ((1 << (d->width)) - 1)
-#define is_power_of_two(i) !(i & ~i)
+#define div_mask(d) ((1 << ((d)->width)) - 1)
+#define is_power_of_two(i) (!((i) & ((i) - 1)))

static unsigned int _get_table_maxdiv(const struct clk_div_table *table)
{
--
1.7.7.6


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