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authorPavel Pisa <ppisa@pikron.com>2006-12-06 17:08:27 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2006-12-07 16:24:15 +0000
commit5c894cd1c89fc10907febd93e6ef35cd3c65e25e (patch)
treea7be88236384910ee326402748f1cafd64b9b5ca
parent9073341c2ba5d5e77b3d05d84cf9e3a16e8a7902 (diff)
[ARM] 3990/1: i.MX/MX1 more precise PLL decode
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>
-rw-r--r--arch/arm/mach-imx/generic.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/arm/mach-imx/generic.c b/arch/arm/mach-imx/generic.c
index 12ea58a3b84..b5aa49d00ca 100644
--- a/arch/arm/mach-imx/generic.c
+++ b/arch/arm/mach-imx/generic.c
@@ -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)