Pileus Git - ~andy/linux/blob - drivers/clk/versatile/clk-vexpress.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License version 2 as
   4  * published by the Free Software Foundation.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9  * GNU General Public License for more details.
  10  *
  11  * Copyright (C) 2012 ARM Limited
  12  */
  13
  14 #include <linux/clkdev.h>
  15 #include <linux/clk-provider.h>
  16 #include <linux/err.h>
  17 #include <linux/of.h>
  18 #include <linux/of_address.h>
  19 #include <linux/vexpress.h>
  20
  21 #include <asm/hardware/sp810.h>
  22
  23 static struct clk *vexpress_sp810_timerclken[4];
  24 static DEFINE_SPINLOCK(vexpress_sp810_lock);
  25
  26 static void __init vexpress_sp810_init(void __iomem *base)
  27 {
  28         int i;
  29
  30         if (WARN_ON(!base))
  31                 return;
  32
  33         for (i = 0; i < ARRAY_SIZE(vexpress_sp810_timerclken); i++) {
  34                 char name[12];
  35                 const char *parents[] = {
  36                         "v2m:refclk32khz", /* REFCLK */
  37                         "v2m:refclk1mhz" /* TIMCLK */
  38                 };
  39
  40                 snprintf(name, ARRAY_SIZE(name), "timerclken%d", i);
  41
  42                 vexpress_sp810_timerclken[i] = clk_register_mux(NULL, name,
  43                                 parents, 2, 0, base + SCCTRL,
  44                                 SCCTRL_TIMERENnSEL_SHIFT(i), 1,
  45                                 0, &vexpress_sp810_lock);
  46
  47                 if (WARN_ON(IS_ERR(vexpress_sp810_timerclken[i])))
  48                         break;
  49         }
  50 }
  51
  52
  53 static const char * const vexpress_clk_24mhz_periphs[] __initconst = {
  54         "mb:uart0", "mb:uart1", "mb:uart2", "mb:uart3",
  55         "mb:mmci", "mb:kmi0", "mb:kmi1"
  56 };
  57
  58 void __init vexpress_clk_init(void __iomem *sp810_base)
  59 {
  60         struct clk *clk;
  61         int i;
  62
  63         clk = clk_register_fixed_rate(NULL, "dummy_apb_pclk", NULL,
  64                         CLK_IS_ROOT, 0);
  65         WARN_ON(clk_register_clkdev(clk, "apb_pclk", NULL));
  66
  67         clk = clk_register_fixed_rate(NULL, "v2m:clk_24mhz", NULL,
  68                         CLK_IS_ROOT, 24000000);
  69         for (i = 0; i < ARRAY_SIZE(vexpress_clk_24mhz_periphs); i++)
  70                 WARN_ON(clk_register_clkdev(clk, NULL,
  71                                 vexpress_clk_24mhz_periphs[i]));
  72
  73         clk = clk_register_fixed_rate(NULL, "v2m:refclk32khz", NULL,
  74                         CLK_IS_ROOT, 32768);
  75         WARN_ON(clk_register_clkdev(clk, NULL, "v2m:wdt"));
  76
  77         clk = clk_register_fixed_rate(NULL, "v2m:refclk1mhz", NULL,
  78                         CLK_IS_ROOT, 1000000);
  79
  80         vexpress_sp810_init(sp810_base);
  81
  82         for (i = 0; i < ARRAY_SIZE(vexpress_sp810_timerclken); i++)
  83                 WARN_ON(clk_set_parent(vexpress_sp810_timerclken[i], clk));
  84
  85         WARN_ON(clk_register_clkdev(vexpress_sp810_timerclken[0],
  86                                 "v2m-timer0", "sp804"));
  87         WARN_ON(clk_register_clkdev(vexpress_sp810_timerclken[1],
  88                                 "v2m-timer1", "sp804"));
  89 }
  90
  91 #if defined(CONFIG_OF)
  92
  93 struct clk *vexpress_sp810_of_get(struct of_phandle_args *clkspec, void *data)
  94 {
  95         if (WARN_ON(clkspec->args_count != 1 || clkspec->args[0] >
  96                         ARRAY_SIZE(vexpress_sp810_timerclken)))
  97                 return NULL;
  98
  99         return vexpress_sp810_timerclken[clkspec->args[0]];
 100 }
 101
 102 void __init vexpress_clk_of_init(void)
 103 {
 104         struct device_node *node;
 105         struct clk *clk;
 106         struct clk *refclk, *timclk;
 107
 108         of_clk_init(NULL);
 109
 110         node = of_find_compatible_node(NULL, NULL, "arm,sp810");
 111         vexpress_sp810_init(of_iomap(node, 0));
 112         of_clk_add_provider(node, vexpress_sp810_of_get, NULL);
 113
 114         /* Select "better" (faster) parent for SP804 timers */
 115         refclk = of_clk_get_by_name(node, "refclk");
 116         timclk = of_clk_get_by_name(node, "timclk");
 117         if (!WARN_ON(IS_ERR(refclk) || IS_ERR(timclk))) {
 118                 int i = 0;
 119
 120                 if (clk_get_rate(refclk) > clk_get_rate(timclk))
 121                         clk = refclk;
 122                 else
 123                         clk = timclk;
 124
 125                 for (i = 0; i < ARRAY_SIZE(vexpress_sp810_timerclken); i++)
 126                         WARN_ON(clk_set_parent(vexpress_sp810_timerclken[i],
 127                                         clk));
 128         }
 129
 130         WARN_ON(clk_register_clkdev(vexpress_sp810_timerclken[0],
 131                                 "v2m-timer0", "sp804"));
 132         WARN_ON(clk_register_clkdev(vexpress_sp810_timerclken[1],
 133                                 "v2m-timer1", "sp804"));
 134 }
 135
 136 #endif