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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>
This commit is contained in:
Sascha Hauer 2012-06-04 14:51:32 +02:00
parent 6cc90d6de1
commit 9ca41bccc3
1 changed files with 55 additions and 25 deletions
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80
arch/arm/mach-imx/clk-pllv2.c
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@ -74,24 +74,15 @@ struct clk_pllv2 {
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 @@ static unsigned long clk_pllv2_recalc_rate(struct clk_hw *hw,
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 @@ static int clk_pllv2_set_rate(struct clk_hw *hw, unsigned long rate,
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 int clk_pllv2_set_rate(struct clk_hw *hw, unsigned long rate,
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)