From: Abel Vesa <abel.vesa@nxp.com>
Date: Fri, 18 Jan 2019 12:54:13 +0000 (+0000)
Subject: clk: imx: Fix fractional clock set rate computation
X-Git-Tag: v5.0-rc5~22^2~2
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=a64a9c088b75cba5840320d57e0bbfb36739c3b5;p=linux.git

clk: imx: Fix fractional clock set rate computation

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: 6209624b9a5c1e ("clk: imx: Add fractional PLL output clock")
Signed-off-by: Abel Vesa <abel.vesa@nxp.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
---

diff --git a/drivers/clk/imx/clk-frac-pll.c b/drivers/clk/imx/clk-frac-pll.c
index 0026c3969b1e..76b9eb15604e 100644
--- a/drivers/clk/imx/clk-frac-pll.c
+++ b/drivers/clk/imx/clk-frac-pll.c
@@ -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;