target/linux/ramips/files/arch/mips/ralink/rt288x/clock.c

   1 /*
   2  *  Ralink RT288X clock API
   3  *
   4  *  Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify it
   7  *  under the terms of the GNU General Public License version 2 as published
   8  *  by the Free Software Foundation.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/init.h>
  14 #include <linux/err.h>
  15 #include <linux/clk.h>
  16
  17 #include <asm/mach-ralink/common.h>
  18 #include <asm/mach-ralink/rt288x.h>
  19 #include <asm/mach-ralink/rt288x_regs.h>
  20 #include "common.h"
  21
  22 struct clk {
  23         unsigned long rate;
  24 };
  25
  26 static struct clk rt288x_cpu_clk;
  27 static struct clk rt288x_sys_clk;
  28 static struct clk rt288x_wdt_clk;
  29 static struct clk rt288x_uart_clk;
  30
  31 void __init rt288x_clocks_init(void)
  32 {
  33         u32     t;
  34
  35         t = rt288x_sysc_rr(SYSC_REG_SYSTEM_CONFIG);
  36         t = ((t >> SYSTEM_CONFIG_CPUCLK_SHIFT) & SYSTEM_CONFIG_CPUCLK_MASK);
  37
  38         switch (t) {
  39         case SYSTEM_CONFIG_CPUCLK_250:
  40                 rt288x_cpu_clk.rate = 250000000;
  41                 break;
  42         case SYSTEM_CONFIG_CPUCLK_266:
  43                 rt288x_cpu_clk.rate = 266666667;
  44                 break;
  45         case SYSTEM_CONFIG_CPUCLK_280:
  46                 rt288x_cpu_clk.rate = 280000000;
  47                 break;
  48         case SYSTEM_CONFIG_CPUCLK_300:
  49                 rt288x_cpu_clk.rate = 300000000;
  50                 break;
  51         }
  52
  53         rt288x_sys_clk.rate = rt288x_cpu_clk.rate / 2;
  54         rt288x_uart_clk.rate = rt288x_sys_clk.rate;
  55         rt288x_wdt_clk.rate = rt288x_sys_clk.rate;
  56 }
  57
  58 /*
  59  * Linux clock API
  60  */
  61 struct clk *clk_get(struct device *dev, const char *id)
  62 {
  63         if (!strcmp(id, "sys"))
  64                 return &rt288x_sys_clk;
  65
  66         if (!strcmp(id, "cpu"))
  67                 return &rt288x_cpu_clk;
  68
  69         if (!strcmp(id, "wdt"))
  70                 return &rt288x_wdt_clk;
  71
  72         if (!strcmp(id, "uart"))
  73                 return &rt288x_uart_clk;
  74
  75         return ERR_PTR(-ENOENT);
  76 }
  77 EXPORT_SYMBOL(clk_get);
  78
  79 int clk_enable(struct clk *clk)
  80 {
  81         return 0;
  82 }
  83 EXPORT_SYMBOL(clk_enable);
  84
  85 void clk_disable(struct clk *clk)
  86 {
  87 }
  88 EXPORT_SYMBOL(clk_disable);
  89
  90 unsigned long clk_get_rate(struct clk *clk)
  91 {
  92         return clk->rate;
  93 }
  94 EXPORT_SYMBOL(clk_get_rate);
  95
  96 void clk_put(struct clk *clk)
  97 {
  98 }
  99 EXPORT_SYMBOL(clk_put);