release/src-rt-6.x.4708/linux/linux-2.6.36/arch/arm/plat-samsung/include/plat/pll6553x.h

   1 /* arch/arm/plat-samsung/include/plat/pll6553x.h
   2  *      partially from arch/arm/mach-s3c64xx/include/mach/pll.h
   3  *
   4  * Copyright 2008 Openmoko, Inc.
   5  * Copyright 2008 Simtec Electronics
   6  *      Ben Dooks <ben@simtec.co.uk>
   7  *      http://armlinux.simtec.co.uk/
   8  *
   9  * Samsung PLL6553x PLL code
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14 */
  15
  16 /* S3C6400 and compatible (S3C2416, etc.) EPLL code */
  17
  18 #define PLL6553X_MDIV_MASK      ((1 << (23-16)) - 1)
  19 #define PLL6553X_PDIV_MASK      ((1 << (13-8)) - 1)
  20 #define PLL6553X_SDIV_MASK      ((1 << (2-0)) - 1)
  21 #define PLL6553X_MDIV_SHIFT     (16)
  22 #define PLL6553X_PDIV_SHIFT     (8)
  23 #define PLL6553X_SDIV_SHIFT     (0)
  24 #define PLL6553X_KDIV_MASK      (0xffff)
  25
  26 static inline unsigned long s3c_get_pll6553x(unsigned long baseclk,
  27                                              u32 pll0, u32 pll1)
  28 {
  29         unsigned long result;
  30         u32 mdiv, pdiv, sdiv, kdiv;
  31         u64 tmp;
  32
  33         mdiv = (pll0 >> PLL6553X_MDIV_SHIFT) & PLL6553X_MDIV_MASK;
  34         pdiv = (pll0 >> PLL6553X_PDIV_SHIFT) & PLL6553X_PDIV_MASK;
  35         sdiv = (pll0 >> PLL6553X_SDIV_SHIFT) & PLL6553X_SDIV_MASK;
  36         kdiv = pll1 & PLL6553X_KDIV_MASK;
  37
  38         /* We need to multiple baseclk by mdiv (the integer part) and kdiv
  39          * which is in 2^16ths, so shift mdiv up (does not overflow) and
  40          * add kdiv before multiplying. The use of tmp is to avoid any
  41          * overflows before shifting bac down into result when multipling
  42          * by the mdiv and kdiv pair.
  43          */
  44
  45         tmp = baseclk;
  46         tmp *= (mdiv << 16) + kdiv;
  47         do_div(tmp, (pdiv << sdiv));
  48         result = tmp >> 16;
  49
  50         return result;
  51 }