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[ARM] 3990/1: i.MX/MX1 more precise PLL decode

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The future high resolution support inclusion utilizes
imx_decode_pll() in timer base frequency computation.
This use requires more precise computation without
discarding 10 bits by shifting left.

Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Pavel Pisa 2006-12-06 17:08:27 +01:00 committed by Russell King
parent 9073341c2b
commit 5c894cd1c8
1 changed files with 8 additions and 1 deletions
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9
arch/arm/mach-imx/generic.c
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@ -104,6 +104,9 @@ EXPORT_SYMBOL(imx_gpio_mode);
*/
static unsigned int imx_decode_pll(unsigned int pll)
{
unsigned long long ll;
unsigned long quot;
u32 mfi = (pll >> 10) & 0xf;
u32 mfn = pll & 0x3ff;
u32 mfd = (pll >> 16) & 0x3ff;
@ -112,7 +115,11 @@ static unsigned int imx_decode_pll(unsigned int pll)
mfi = mfi <= 5 ? 5 : mfi;
return (2 * (f_ref>>10) * ( (mfi<<10) + (mfn<<10) / (mfd+1) )) / (pd+1);
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 int) ll;
}
unsigned int imx_get_system_clk(void)