kernel/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 void __init imx_check_clocks(struct clk *clks[], unsigned int count)
  11 {
  12         unsigned i;
  13
  14         for (i = 0; i < count; i++)
  15                 if (IS_ERR(clks[i]))
  16                         pr_err("i.MX clk %u: register failed with %ld\n",
  17                                i, PTR_ERR(clks[i]));
  18 }
  19
  20 static struct clk * __init imx_obtain_fixed_clock_from_dt(const char *name)
  21 {
  22         struct of_phandle_args phandle;
  23         struct clk *clk = ERR_PTR(-ENODEV);
  24         char *path;
  25
  26         path = kasprintf(GFP_KERNEL, "/clocks/%s", name);
  27         if (!path)
  28                 return ERR_PTR(-ENOMEM);
  29
  30         phandle.np = of_find_node_by_path(path);
  31         kfree(path);
  32
  33         if (phandle.np) {
  34                 clk = of_clk_get_from_provider(&phandle);
  35                 of_node_put(phandle.np);
  36         }
  37         return clk;
  38 }
  39
  40 struct clk * __init imx_obtain_fixed_clock(
  41                         const char *name, unsigned long rate)
  42 {
  43         struct clk *clk;
  44
  45         clk = imx_obtain_fixed_clock_from_dt(name);
  46         if (IS_ERR(clk))
  47                 clk = imx_clk_fixed(name, rate);
  48         return clk;
  49 }
  50
  51 /*
  52  * This fixups the register CCM_CSCMR1 write value.
  53  * The write/read/divider values of the aclk_podf field
  54  * of that register have the relationship described by
  55  * the following table:
  56  *
  57  * write value       read value        divider
  58  * 3b'000            3b'110            7
  59  * 3b'001            3b'111            8
  60  * 3b'010            3b'100            5
  61  * 3b'011            3b'101            6
  62  * 3b'100            3b'010            3
  63  * 3b'101            3b'011            4
  64  * 3b'110            3b'000            1
  65  * 3b'111            3b'001            2(default)
  66  *
  67  * That's why we do the xor operation below.
  68  */
  69 #define CSCMR1_FIXUP    0x00600000
  70
  71 void imx_cscmr1_fixup(u32 *val)
  72 {
  73         *val ^= CSCMR1_FIXUP;
  74         return;
  75 }