| Message ID | 20130116005639.8920.45989@quantum (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 16/01/13 00:56, Mike Turquette wrote: > Quoting Joe Perches (2013-01-15 10:31:05) >> On Tue, 2013-01-15 at 10:28 +0000, James Hogan wrote: >>> 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)). >> [] >>> diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c >> [] >>> @@ -29,8 +29,8 @@ >> [] >>> -#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))) >> >> Use is_power_of_2 in log2.h instead? > > Both are fine suggestions. How about I apply the below patch? Looks good to me, thanks for taking care of the log.h change. Cheers James > From 54c6c9e5f61693effbe6e4fb28ef9f2f9b3d7a23 Mon Sep 17 00:00:00 2001 > From: James Hogan <james.hogan@imgtec.com> > Date: Tue, 15 Jan 2013 10:28:05 +0000 > Subject: [PATCH] clk-divider: fix macros > > The macro is_power_of_two() in clk-divider.c was defined as !(i & ~i) > which is always true. Instead use is_power_of_2() from log2.h. > > Also add brackets around the macro arguments in div_mask to avoid any > future operator precedence problems. > > Signed-off-by: James Hogan <james.hogan@imgtec.com> > Cc: Joe Perches <joe@perches.com> > Signed-off-by: Mike Turquette <mturquette@linaro.org> > [mturquette@linaro.org: use log2.h per Joe Perches; update changelog] > --- > drivers/clk/clk-divider.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c > index a9204c6..68b4021 100644 > --- a/drivers/clk/clk-divider.c > +++ b/drivers/clk/clk-divider.c > @@ -16,6 +16,7 @@ > #include <linux/io.h> > #include <linux/err.h> > #include <linux/string.h> > +#include <linux/log2.h> > > /* > * DOC: basic adjustable divider clock that cannot gate > @@ -29,8 +30,7 @@ > > #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) > > static unsigned int _get_table_maxdiv(const struct clk_div_table *table) > { > @@ -137,7 +137,7 @@ static bool _is_valid_table_div(const struct clk_div_table *table, > static bool _is_valid_div(struct clk_divider *divider, unsigned int div) > { > if (divider->flags & CLK_DIVIDER_POWER_OF_TWO) > - return is_power_of_two(div); > + return is_power_of_2(div); > if (divider->table) > return _is_valid_table_div(divider->table, div); > return true; >
diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c index a9204c6..68b4021 100644 --- a/drivers/clk/clk-divider.c +++ b/drivers/clk/clk-divider.c @@ -16,6 +16,7 @@ #include <linux/io.h> #include <linux/err.h> #include <linux/string.h> +#include <linux/log2.h> /* * DOC: basic adjustable divider clock that cannot gate @@ -29,8 +30,7 @@ #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) static unsigned int _get_table_maxdiv(const struct clk_div_table *table) { @@ -137,7 +137,7 @@ static bool _is_valid_table_div(const struct clk_div_table *table, static bool _is_valid_div(struct clk_divider *divider, unsigned int div) { if (divider->flags & CLK_DIVIDER_POWER_OF_TWO) - return is_power_of_two(div); + return is_power_of_2(div); if (divider->table) return _is_valid_table_div(divider->table, div); return true;