arch/arm/mach-imx/clk.c

   1 #include <linux/clk.h>
   2 #include <linux/err.h>
   3 #include <linux/of.h>
   4 #include <linux/slab.h>
   5 #include <linux/spinlock.h>
   6 #include "clk.h"
   7
   8 DEFINE_SPINLOCK(imx_ccm_lock);
   9
  10 static struct clk * __init imx_obtain_fixed_clock_from_dt(const char *name)
  11 {
  12         struct of_phandle_args phandle;
  13         struct clk *clk = ERR_PTR(-ENODEV);
  14         char *path;
  15
  16         path = kasprintf(GFP_KERNEL, "/clocks/%s", name);
  17         if (!path)
  18                 return ERR_PTR(-ENOMEM);
  19
  20         phandle.np = of_find_node_by_path(path);
  21         kfree(path);
  22
  23         if (phandle.np) {
  24                 clk = of_clk_get_from_provider(&phandle);
  25                 of_node_put(phandle.np);
  26         }
  27         return clk;
  28 }
  29
  30 struct clk * __init imx_obtain_fixed_clock(
  31                         const char *name, unsigned long rate)
  32 {
  33         struct clk *clk;
  34
  35         clk = imx_obtain_fixed_clock_from_dt(name);
  36         if (IS_ERR(clk))
  37                 clk = imx_clk_fixed(name, rate);
  38         return clk;
  39 }
  40
  41 /*
  42  * This fixups the register CCM_CSCMR1 write value.
  43  * The write/read/divider values of the aclk_podf field
  44  * of that register have the relationship described by
  45  * the following table:
  46  *
  47  * write value       read value        divider
  48  * 3b'000            3b'110            7
  49  * 3b'001            3b'111            8
  50  * 3b'010            3b'100            5
  51  * 3b'011            3b'101            6
  52  * 3b'100            3b'010            3
  53  * 3b'101            3b'011            4
  54  * 3b'110            3b'000            1
  55  * 3b'111            3b'001            2(default)
  56  *
  57  * That's why we do the xor operation below.
  58  */
  59 #define CSCMR1_FIXUP    0x00600000
  60
  61 void imx_cscmr1_fixup(u32 *val)
  62 {
  63         *val ^= CSCMR1_FIXUP;
  64         return;
  65 }