ARM i.MX pllv2: make round_rate accurate
in round_rate we made the assumption that we can set arbitrary
frequencies and thus returned the input rate. This is not correct,
for certain frequencies after setting a frequency with set_rate,
recalc_rate will return different values. To fix this, introduce
set_rate/recalc_rate functions which work on variables instead
of registers directly. This way we can call these in round_rate
to get the exact rate which we would get if we call set_rate
with this value.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
diff --git a/arch/arm/mach-imx/clk-pllv2.c b/arch/arm/mach-imx/clk-pllv2.c
index 1b03071..0440379 100644
--- a/arch/arm/mach-imx/clk-pllv2.c
+++ b/arch/arm/mach-imx/clk-pllv2.c
@@ -74,24 +74,15 @@
void __iomem *base;
};
-static unsigned long clk_pllv2_recalc_rate(struct clk_hw *hw,
- unsigned long parent_rate)
+static unsigned long __clk_pllv2_recalc_rate(unsigned long parent_rate,
+ u32 dp_ctl, u32 dp_op, u32 dp_mfd, u32 dp_mfn)
{
long mfi, mfn, mfd, pdf, ref_clk, mfn_abs;
- unsigned long dp_op, dp_mfd, dp_mfn, dp_ctl, dbl;
- void __iomem *pllbase;
+ unsigned long dbl;
s64 temp;
- struct clk_pllv2 *pll = to_clk_pllv2(hw);
- pllbase = pll->base;
-
- dp_ctl = __raw_readl(pllbase + MXC_PLL_DP_CTL);
dbl = dp_ctl & MXC_PLL_DP_CTL_DPDCK0_2_EN;
- dp_op = __raw_readl(pllbase + MXC_PLL_DP_OP);
- dp_mfd = __raw_readl(pllbase + MXC_PLL_DP_MFD);
- dp_mfn = __raw_readl(pllbase + MXC_PLL_DP_MFN);
-
pdf = dp_op & MXC_PLL_DP_OP_PDF_MASK;
mfi = (dp_op & MXC_PLL_DP_OP_MFI_MASK) >> MXC_PLL_DP_OP_MFI_OFFSET;
mfi = (mfi <= 5) ? 5 : mfi;
@@ -117,18 +108,30 @@
return temp;
}
-static int clk_pllv2_set_rate(struct clk_hw *hw, unsigned long rate,
+static unsigned long clk_pllv2_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
- struct clk_pllv2 *pll = to_clk_pllv2(hw);
- u32 reg;
+ u32 dp_op, dp_mfd, dp_mfn, dp_ctl;
void __iomem *pllbase;
+ struct clk_pllv2 *pll = to_clk_pllv2(hw);
+
+ pllbase = pll->base;
+
+ dp_ctl = __raw_readl(pllbase + MXC_PLL_DP_CTL);
+ dp_op = __raw_readl(pllbase + MXC_PLL_DP_OP);
+ dp_mfd = __raw_readl(pllbase + MXC_PLL_DP_MFD);
+ dp_mfn = __raw_readl(pllbase + MXC_PLL_DP_MFN);
+
+ return __clk_pllv2_recalc_rate(parent_rate, dp_ctl, dp_op, dp_mfd, dp_mfn);
+}
+
+static int __clk_pllv2_set_rate(unsigned long rate, unsigned long parent_rate,
+ u32 *dp_op, u32 *dp_mfd, u32 *dp_mfn)
+{
+ u32 reg;
long mfi, pdf, mfn, mfd = 999999;
s64 temp64;
unsigned long quad_parent_rate;
- unsigned long dp_ctl;
-
- pllbase = pll->base;
quad_parent_rate = 4 * parent_rate;
pdf = mfi = -1;
@@ -138,18 +141,41 @@
return -EINVAL;
pdf--;
- temp64 = rate * (pdf+1) - quad_parent_rate * mfi;
- do_div(temp64, quad_parent_rate/1000000);
+ temp64 = rate * (pdf + 1) - quad_parent_rate * mfi;
+ do_div(temp64, quad_parent_rate / 1000000);
mfn = (long)temp64;
+ reg = mfi << 4 | pdf;
+
+ *dp_op = reg;
+ *dp_mfd = mfd;
+ *dp_mfn = mfn;
+
+ return 0;
+}
+
+static int clk_pllv2_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct clk_pllv2 *pll = to_clk_pllv2(hw);
+ void __iomem *pllbase;
+ u32 dp_ctl, dp_op, dp_mfd, dp_mfn;
+ int ret;
+
+ pllbase = pll->base;
+
+
+ ret = __clk_pllv2_set_rate(rate, parent_rate, &dp_op, &dp_mfd, &dp_mfn);
+ if (ret)
+ return ret;
+
dp_ctl = __raw_readl(pllbase + MXC_PLL_DP_CTL);
/* use dpdck0_2 */
__raw_writel(dp_ctl | 0x1000L, pllbase + MXC_PLL_DP_CTL);
- reg = mfi << 4 | pdf;
- __raw_writel(reg, pllbase + MXC_PLL_DP_OP);
- __raw_writel(mfd, pllbase + MXC_PLL_DP_MFD);
- __raw_writel(mfn, pllbase + MXC_PLL_DP_MFN);
+ __raw_writel(dp_op, pllbase + MXC_PLL_DP_OP);
+ __raw_writel(dp_mfd, pllbase + MXC_PLL_DP_MFD);
+ __raw_writel(dp_mfn, pllbase + MXC_PLL_DP_MFN);
return 0;
}
@@ -157,7 +183,11 @@
static long clk_pllv2_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
- return rate;
+ u32 dp_op, dp_mfd, dp_mfn;
+
+ __clk_pllv2_set_rate(rate, *prate, &dp_op, &dp_mfd, &dp_mfn);
+ return __clk_pllv2_recalc_rate(*prate, MXC_PLL_DP_CTL_DPDCK0_2_EN,
+ dp_op, dp_mfd, dp_mfn);
}
static int clk_pllv2_prepare(struct clk_hw *hw)