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/amba/sp810.h>
  15 #include <linux/clkdev.h>
  16 #include <linux/clk-provider.h>
  17 #include <linux/err.h>
  18 #include <linux/of.h>
  19 #include <linux/of_address.h>
  20 #include <linux/vexpress.h>
  21
  22 static struct clk *vexpress_sp810_timerclken[4];
  23 static DEFINE_SPINLOCK(vexpress_sp810_lock);
  24
  25 static void __init vexpress_sp810_init(void __iomem *base)
  26 {
  27         int i;
  28
  29         if (WARN_ON(!base))
  30                 return;
  31
  32         for (i = 0; i < ARRAY_SIZE(vexpress_sp810_timerclken); i++) {
  33                 char name[12];
  34                 const char *parents[] = {
  35                         "v2m:refclk32khz", /* REFCLK */
  36                         "v2m:refclk1mhz" /* TIMCLK */
  37                 };
  38
  39                 snprintf(name, ARRAY_SIZE(name), "timerclken%d", i);
  40
  41                 vexpress_sp810_timerclken[i] = clk_register_mux(NULL, name,
  42                                 parents, 2, 0, base + SCCTRL,
  43                                 SCCTRL_TIMERENnSEL_SHIFT(i), 1,
  44                                 0, &vexpress_sp810_lock);
  45
  46                 if (WARN_ON(IS_ERR(vexpress_sp810_timerclken[i])))
  47                         break;
  48         }
  49 }
  50
  51
  52 static const char * const vexpress_clk_24mhz_periphs[] __initconst = {
  53         "mb:uart0", "mb:uart1", "mb:uart2", "mb:uart3",
  54         "mb:mmci", "mb:kmi0", "mb:kmi1"
  55 };
  56
  57 void __init vexpress_clk_init(void __iomem *sp810_base)
  58 {
  59         struct clk *clk;
  60         int i;
  61
  62         clk = clk_register_fixed_rate(NULL, "dummy_apb_pclk", NULL,
  63                         CLK_IS_ROOT, 0);
  64         WARN_ON(clk_register_clkdev(clk, "apb_pclk", NULL));
  65
  66         clk = clk_register_fixed_rate(NULL, "v2m:clk_24mhz", NULL,
  67                         CLK_IS_ROOT, 24000000);
  68         for (i = 0; i < ARRAY_SIZE(vexpress_clk_24mhz_periphs); i++)
  69                 WARN_ON(clk_register_clkdev(clk, NULL,
  70                                 vexpress_clk_24mhz_periphs[i]));
  71
  72         clk = clk_register_fixed_rate(NULL, "v2m:refclk32khz", NULL,
  73                         CLK_IS_ROOT, 32768);
  74         WARN_ON(clk_register_clkdev(clk, NULL, "v2m:wdt"));
  75
  76         clk = clk_register_fixed_rate(NULL, "v2m:refclk1mhz", NULL,
  77                         CLK_IS_ROOT, 1000000);
  78
  79         vexpress_sp810_init(sp810_base);
  80
  81         for (i = 0; i < ARRAY_SIZE(vexpress_sp810_timerclken); i++)
  82                 WARN_ON(clk_set_parent(vexpress_sp810_timerclken[i], clk));
  83
  84         WARN_ON(clk_register_clkdev(vexpress_sp810_timerclken[0],
  85                                 "v2m-timer0", "sp804"));
  86         WARN_ON(clk_register_clkdev(vexpress_sp810_timerclken[1],
  87                                 "v2m-timer1", "sp804"));
  88 }
  89
  90 #if defined(CONFIG_OF)
  91
  92 struct clk *vexpress_sp810_of_get(struct of_phandle_args *clkspec, void *data)
  93 {
  94         if (WARN_ON(clkspec->args_count != 1 || clkspec->args[0] >
  95                         ARRAY_SIZE(vexpress_sp810_timerclken)))
  96                 return NULL;
  97
  98         return vexpress_sp810_timerclken[clkspec->args[0]];
  99 }
 100
 101 void __init vexpress_clk_of_init(void)
 102 {
 103         struct device_node *node;
 104         struct clk *clk;
 105         struct clk *refclk, *timclk;
 106
 107         of_clk_init(NULL);
 108
 109         node = of_find_compatible_node(NULL, NULL, "arm,sp810");
 110         vexpress_sp810_init(of_iomap(node, 0));
 111         of_clk_add_provider(node, vexpress_sp810_of_get, NULL);
 112
 113         /* Select "better" (faster) parent for SP804 timers */
 114         refclk = of_clk_get_by_name(node, "refclk");
 115         timclk = of_clk_get_by_name(node, "timclk");
 116         if (!WARN_ON(IS_ERR(refclk) || IS_ERR(timclk))) {
 117                 int i = 0;
 118
 119                 if (clk_get_rate(refclk) > clk_get_rate(timclk))
 120                         clk = refclk;
 121                 else
 122                         clk = timclk;
 123
 124                 for (i = 0; i < ARRAY_SIZE(vexpress_sp810_timerclken); i++)
 125                         WARN_ON(clk_set_parent(vexpress_sp810_timerclken[i],
 126                                         clk));
 127         }
 128
 129         WARN_ON(clk_register_clkdev(vexpress_sp810_timerclken[0],
 130                                 "v2m-timer0", "sp804"));
 131         WARN_ON(clk_register_clkdev(vexpress_sp810_timerclken[1],
 132                                 "v2m-timer1", "sp804"));
 133 }
 134
 135 #endif