clk->rate = parent->rate / div * mult The formula is OK. But it may overflow while we do operate with unsigned long. So use do_div instead.
Signed-off-by: Haojian Zhuang <haojian.zhu...@gmail.com> --- drivers/clk/clk-fixed-factor.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/clk/clk-fixed-factor.c b/drivers/clk/clk-fixed-factor.c index a489985..1ef271e 100644 --- a/drivers/clk/clk-fixed-factor.c +++ b/drivers/clk/clk-fixed-factor.c @@ -28,8 +28,11 @@ static unsigned long clk_factor_recalc_rate(struct clk_hw *hw, unsigned long parent_rate) { struct clk_fixed_factor *fix = to_clk_fixed_factor(hw); + unsigned long long int rate; - return parent_rate * fix->mult / fix->div; + rate = (unsigned long long int)parent_rate * fix->mult; + do_div(rate, fix->div); + return (unsigned long)rate; } static long clk_factor_round_rate(struct clk_hw *hw, unsigned long rate, -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/