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[ARM] MXC: Use a single function for decoding a PLL

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We had 3 versions of this function in clock support for MX1/2/3
Use a single one instead. I picked the one from the MX3 as it seems
to calculate more accurate as the other ones. Also, on MX27 and MX31 mfn
can be negative, this hasn't been handled correctly on MX27 since now.

This patch has been tested on MX27 and MX31 and produces the same clock
frequencies for me.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This commit is contained in:
Sascha Hauer
2009-01-26 15:41:16 +01:00
parent 5512e88f3a
commit a2865197a5
5 changed files with 57 additions and 88 deletions
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31
arch/arm/mach-mx1/clock.c
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@@ -87,33 +87,6 @@ static int _clk_parent_set_rate(struct clk *clk, unsigned long rate)
return clk->parent->set_rate(clk->parent, rate);
}
/*
* get the system pll clock in Hz
*
* mfi + mfn / (mfd +1)
* f = 2 * f_ref * --------------------
* pd + 1
*/
static unsigned long mx1_decode_pll(unsigned int pll, u32 f_ref)
{
unsigned long long ll;
unsigned long quot;
u32 mfi = (pll >> 10) & 0xf;
u32 mfn = pll & 0x3ff;
u32 mfd = (pll >> 16) & 0x3ff;
u32 pd = (pll >> 26) & 0xf;
mfi = mfi <= 5 ? 5 : mfi;
ll = 2 * (unsigned long long)f_ref *
((mfi << 16) + (mfn << 16) / (mfd + 1));
quot = (pd + 1) * (1 << 16);
ll += quot / 2;
do_div(ll, quot);
return (unsigned long)ll;
}
static unsigned long clk16m_get_rate(struct clk *clk)
{
return 16000000;
@@ -188,7 +161,7 @@ static struct clk prem_clk = {
static unsigned long system_clk_get_rate(struct clk *clk)
{
return mx1_decode_pll(__raw_readl(CCM_SPCTL0),
return mxc_decode_pll(__raw_readl(CCM_SPCTL0),
clk_get_rate(clk->parent));
}
@@ -200,7 +173,7 @@ static struct clk system_clk = {
static unsigned long mcu_clk_get_rate(struct clk *clk)
{
return mx1_decode_pll(__raw_readl(CCM_MPCTL0),
return mxc_decode_pll(__raw_readl(CCM_MPCTL0),
clk_get_rate(clk->parent));
}