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clock.c

/*
 * TI DaVinci clock config file
 *
 * Copyright (C) 2006 Texas Instruments.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>

#include <asm/hardware.h>
#include <asm/io.h>

#include <asm/arch/psc.h>
#include "clock.h"

/* PLL/Reset register offsets */
#define PLLM            0x110

static LIST_HEAD(clocks);
static DEFINE_MUTEX(clocks_mutex);
static DEFINE_SPINLOCK(clockfw_lock);

static unsigned int commonrate;
static unsigned int armrate;
static unsigned int fixedrate = 27000000; /* 27 MHZ */

extern void davinci_psc_config(unsigned int domain, unsigned int id, char enable);

/*
 * Returns a clock. Note that we first try to use device id on the bus
 * and clock name. If this fails, we try to use clock name only.
 */
struct clk *clk_get(struct device *dev, const char *id)
{
      struct clk *p, *clk = ERR_PTR(-ENOENT);
      int idno;

      if (dev == NULL || dev->bus != &platform_bus_type)
            idno = -1;
      else
            idno = to_platform_device(dev)->id;

      mutex_lock(&clocks_mutex);

      list_for_each_entry(p, &clocks, node) {
            if (p->id == idno &&
                strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
                  clk = p;
                  goto found;
            }
      }

      list_for_each_entry(p, &clocks, node) {
            if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
                  clk = p;
                  break;
            }
      }

found:
      mutex_unlock(&clocks_mutex);

      return clk;
}
EXPORT_SYMBOL(clk_get);

void clk_put(struct clk *clk)
{
      if (clk && !IS_ERR(clk))
            module_put(clk->owner);
}
EXPORT_SYMBOL(clk_put);

static int __clk_enable(struct clk *clk)
{
      if (clk->flags & ALWAYS_ENABLED)
            return 0;

      davinci_psc_config(DAVINCI_GPSC_ARMDOMAIN, clk->lpsc, 1);
      return 0;
}

static void __clk_disable(struct clk *clk)
{
      if (clk->usecount)
            return;

      davinci_psc_config(DAVINCI_GPSC_ARMDOMAIN, clk->lpsc, 0);
}

int clk_enable(struct clk *clk)
{
      unsigned long flags;
      int ret = 0;

      if (clk == NULL || IS_ERR(clk))
            return -EINVAL;

      if (clk->usecount++ == 0) {
            spin_lock_irqsave(&clockfw_lock, flags);
            ret = __clk_enable(clk);
            spin_unlock_irqrestore(&clockfw_lock, flags);
      }

      return ret;
}
EXPORT_SYMBOL(clk_enable);

void clk_disable(struct clk *clk)
{
      unsigned long flags;

      if (clk == NULL || IS_ERR(clk))
            return;

      if (clk->usecount > 0 && !(--clk->usecount)) {
            spin_lock_irqsave(&clockfw_lock, flags);
            __clk_disable(clk);
            spin_unlock_irqrestore(&clockfw_lock, flags);
      }
}
EXPORT_SYMBOL(clk_disable);

unsigned long clk_get_rate(struct clk *clk)
{
      if (clk == NULL || IS_ERR(clk))
            return -EINVAL;

      return *(clk->rate);
}
EXPORT_SYMBOL(clk_get_rate);

long clk_round_rate(struct clk *clk, unsigned long rate)
{
      if (clk == NULL || IS_ERR(clk))
            return -EINVAL;

      return *(clk->rate);
}
EXPORT_SYMBOL(clk_round_rate);

int clk_set_rate(struct clk *clk, unsigned long rate)
{
      if (clk == NULL || IS_ERR(clk))
            return -EINVAL;

      /* changing the clk rate is not supported */
      return -EINVAL;
}
EXPORT_SYMBOL(clk_set_rate);

int clk_register(struct clk *clk)
{
      if (clk == NULL || IS_ERR(clk))
            return -EINVAL;

      mutex_lock(&clocks_mutex);
      list_add(&clk->node, &clocks);
      mutex_unlock(&clocks_mutex);

      return 0;
}
EXPORT_SYMBOL(clk_register);

void clk_unregister(struct clk *clk)
{
      if (clk == NULL || IS_ERR(clk))
            return;

      mutex_lock(&clocks_mutex);
      list_del(&clk->node);
      mutex_unlock(&clocks_mutex);
}
EXPORT_SYMBOL(clk_unregister);

static struct clk davinci_clks[] = {
      {
            .name = "ARMCLK",
            .rate = &armrate,
            .lpsc = -1,
            .flags = ALWAYS_ENABLED,
      },
      {
            .name = "UART",
            .rate = &fixedrate,
            .lpsc = DAVINCI_LPSC_UART0,
      },
      {
            .name = "EMACCLK",
            .rate = &commonrate,
            .lpsc = DAVINCI_LPSC_EMAC_WRAPPER,
      },
      {
            .name = "I2CCLK",
            .rate = &fixedrate,
            .lpsc = DAVINCI_LPSC_I2C,
      },
      {
            .name = "IDECLK",
            .rate = &commonrate,
            .lpsc = DAVINCI_LPSC_ATA,
      },
      {
            .name = "McBSPCLK",
            .rate = &commonrate,
            .lpsc = DAVINCI_LPSC_McBSP,
      },
      {
            .name = "MMCSDCLK",
            .rate = &commonrate,
            .lpsc = DAVINCI_LPSC_MMC_SD,
      },
      {
            .name = "SPICLK",
            .rate = &commonrate,
            .lpsc = DAVINCI_LPSC_SPI,
      },
      {
            .name = "gpio",
            .rate = &commonrate,
            .lpsc = DAVINCI_LPSC_GPIO,
      },
      {
            .name = "AEMIFCLK",
            .rate = &commonrate,
            .lpsc = DAVINCI_LPSC_AEMIF,
            .usecount = 1,
      }
};

int __init davinci_clk_init(void)
{
      struct clk *clkp;
      int count = 0;
      u32 pll_mult;

      pll_mult = davinci_readl(DAVINCI_PLL_CNTRL0_BASE + PLLM);
      commonrate = ((pll_mult + 1) * 27000000) / 6;
      armrate = ((pll_mult + 1) * 27000000) / 2;

      for (clkp = davinci_clks; count < ARRAY_SIZE(davinci_clks);
           count++, clkp++) {
            clk_register(clkp);

            /* Turn on clocks that have been enabled in the
             * table above */
            if (clkp->usecount)
                  clk_enable(clkp);
      }

      return 0;
}

#ifdef CONFIG_PROC_FS
#include <linux/proc_fs.h>
#include <linux/seq_file.h>

static void *davinci_ck_start(struct seq_file *m, loff_t *pos)
{
      return *pos < 1 ? (void *)1 : NULL;
}

static void *davinci_ck_next(struct seq_file *m, void *v, loff_t *pos)
{
      ++*pos;
      return NULL;
}

static void davinci_ck_stop(struct seq_file *m, void *v)
{
}

static int davinci_ck_show(struct seq_file *m, void *v)
{
      struct clk *cp;

      list_for_each_entry(cp, &clocks, node)
            seq_printf(m,"%s %d %d\n", cp->name, *(cp->rate), cp->usecount);

      return 0;
}

static const struct seq_operations davinci_ck_op = {
      .start      = davinci_ck_start,
      .next = davinci_ck_next,
      .stop = davinci_ck_stop,
      .show = davinci_ck_show
};

static int davinci_ck_open(struct inode *inode, struct file *file)
{
      return seq_open(file, &davinci_ck_op);
}

static const struct file_operations proc_davinci_ck_operations = {
      .open       = davinci_ck_open,
      .read       = seq_read,
      .llseek           = seq_lseek,
      .release    = seq_release,
};

static int __init davinci_ck_proc_init(void)
{
      proc_create("davinci_clocks", 0, NULL, &proc_davinci_ck_operations);
      return 0;

}
__initcall(davinci_ck_proc_init);
#endif      /* CONFIG_DEBUG_PROC_FS */

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