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clk: mmp: fix the wrong calculation formula

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The formula is numerator/denominator = Fin / (Fout * factor)
So
Fout = Fin * denominator / (numerator * factor).
Current clk_factor_round_rate and clk_factor_recalc_rate use
wrong formula. This patch will fix them.

Signed-off-by: Chao Xie <chao.xie@marvell.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
This commit is contained in:
Chao Xie 2014-01-23 10:47:41 +08:00 committed by Mike Turquette
parent 7433ab43fa
commit c45693a648
1 changed files with 5 additions and 5 deletions
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10
drivers/clk/mmp/clk-frac.c
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@ -40,12 +40,12 @@ static long clk_factor_round_rate(struct clk_hw *hw, unsigned long drate,
for (i = 0; i < factor->ftbl_cnt; i++) {
prev_rate = rate;
rate = (((*prate / 10000) * factor->ftbl[i].num) /
(factor->ftbl[i].den * factor->masks->factor)) * 10000;
rate = (((*prate / 10000) * factor->ftbl[i].den) /
(factor->ftbl[i].num * factor->masks->factor)) * 10000;
if (rate > drate)
break;
}
if (i == 0)
if ((i == 0) || (i == factor->ftbl_cnt))
return rate;
else
return prev_rate;
@ -85,8 +85,8 @@ static int clk_factor_set_rate(struct clk_hw *hw, unsigned long drate,
for (i = 0; i < factor->ftbl_cnt; i++) {
prev_rate = rate;
rate = (((prate / 10000) * factor->ftbl[i].num) /
(factor->ftbl[i].den * factor->masks->factor)) * 10000;
rate = (((prate / 10000) * factor->ftbl[i].den) /
(factor->ftbl[i].num * factor->masks->factor)) * 10000;
if (rate > drate)
break;
}