arch/arm/mach-w90x900/clksel.c

   1 /*
   2  * linux/arch/arm/mach-w90x900/clksel.c
   3  *
   4  * Copyright (c) 2008 Nuvoton technology corporation
   5  *
   6  * Wan ZongShun <mcuos.com@gmail.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation;version 2 of the License.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/kernel.h>
  15 #include <linux/device.h>
  16 #include <linux/list.h>
  17 #include <linux/errno.h>
  18 #include <linux/err.h>
  19 #include <linux/string.h>
  20 #include <linux/clk.h>
  21 #include <linux/mutex.h>
  22 #include <linux/io.h>
  23
  24 #include <mach/hardware.h>
  25 #include <mach/regs-clock.h>
  26
  27 #define PLL0            0x00
  28 #define PLL1            0x01
  29 #define OTHER           0x02
  30 #define EXT             0x03
  31 #define MSOFFSET        0x0C
  32 #define ATAOFFSET       0x0a
  33 #define LCDOFFSET       0x06
  34 #define AUDOFFSET       0x04
  35 #define CPUOFFSET       0x00
  36
  37 static DEFINE_MUTEX(clksel_sem);
  38
  39 static void clock_source_select(const char *dev_id, unsigned int clkval)
  40 {
  41         unsigned int clksel, offset;
  42
  43         clksel = __raw_readl(REG_CLKSEL);
  44
  45         if (strcmp(dev_id, "nuc900-ms") == 0)
  46                 offset = MSOFFSET;
  47         else if (strcmp(dev_id, "nuc900-atapi") == 0)
  48                 offset = ATAOFFSET;
  49         else if (strcmp(dev_id, "nuc900-lcd") == 0)
  50                 offset = LCDOFFSET;
  51         else if (strcmp(dev_id, "nuc900-audio") == 0)
  52                 offset = AUDOFFSET;
  53         else
  54                 offset = CPUOFFSET;
  55
  56         clksel &= ~(0x03 << offset);
  57         clksel |= (clkval << offset);
  58
  59         __raw_writel(clksel, REG_CLKSEL);
  60 }
  61
  62 void nuc900_clock_source(struct device *dev, unsigned char *src)
  63 {
  64         unsigned int clkval;
  65         const char *dev_id;
  66
  67         BUG_ON(!src);
  68         clkval = 0;
  69
  70         mutex_lock(&clksel_sem);
  71
  72         if (dev)
  73                 dev_id = dev_name(dev);
  74         else
  75                 dev_id = "cpufreq";
  76
  77         if (strcmp(src, "pll0") == 0)
  78                 clkval = PLL0;
  79         else if (strcmp(src, "pll1") == 0)
  80                 clkval = PLL1;
  81         else if (strcmp(src, "ext") == 0)
  82                 clkval = EXT;
  83         else if (strcmp(src, "oth") == 0)
  84                 clkval = OTHER;
  85
  86         clock_source_select(dev_id, clkval);
  87
  88         mutex_unlock(&clksel_sem);
  89 }
  90 EXPORT_SYMBOL(nuc900_clock_source);
  91