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clk: imx: Fix fractional clock set rate computation

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Before multiplying by PLL_FRAC_DENOM, the temp64 needs to be
 temp64 = rate * 2 - divfi * parent_rate * 8, instead of:
 temp64 = (rate * 2 - divfi) * parent_rate

Fixes: 6209624b9a ("clk: imx: Add fractional PLL output clock")
Signed-off-by: Abel Vesa <abel.vesa@nxp.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
This commit is contained in:
Abel Vesa 2019-01-18 12:54:13 +00:00 committed by Stephen Boyd
parent ede7785847
commit a64a9c088b
1 changed files with 3 additions and 2 deletions
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5
drivers/clk/imx/clk-frac-pll.c
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@ -155,13 +155,14 @@ static int clk_pll_set_rate(struct clk_hw *hw, unsigned long rate,
{
struct clk_frac_pll *pll = to_clk_frac_pll(hw);
u32 val, divfi, divff;
u64 temp64 = parent_rate;
u64 temp64;
int ret;
parent_rate *= 8;
rate *= 2;
divfi = rate / parent_rate;
temp64 *= rate - divfi;
temp64 = parent_rate * divfi;
temp64 = rate - temp64;
temp64 *= PLL_FRAC_DENOM;
do_div(temp64, parent_rate);
divff = temp64;