LXR linux/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
  22static struct clk *vexpress_sp810_timerclken[4];
  23static DEFINE_SPINLOCK(vexpress_sp810_lock);
  24
  25static 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
  52static 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
  57void __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
  92struct 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
 101void __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
 136