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clock.c

/* arch/arm/mach-msm/clock.c
 *
 * Copyright (C) 2007 Google, Inc.
 * Copyright (c) 2007 QUALCOMM Incorporated
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.      See the
 * GNU General Public License for more details.
 *
 */

#include <linux/version.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/spinlock.h>

#include "clock.h"
#include "proc_comm.h"

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

/*
 * glue for the proc_comm interface
 */
static inline int pc_clk_enable(unsigned id)
{
      return msm_proc_comm(PCOM_CLKCTL_RPC_ENABLE, &id, NULL);
}

static inline void pc_clk_disable(unsigned id)
{
      msm_proc_comm(PCOM_CLKCTL_RPC_DISABLE, &id, NULL);
}

static inline int pc_clk_set_rate(unsigned id, unsigned rate)
{
      return msm_proc_comm(PCOM_CLKCTL_RPC_SET_RATE, &id, &rate);
}

static inline int pc_clk_set_min_rate(unsigned id, unsigned rate)
{
      return msm_proc_comm(PCOM_CLKCTL_RPC_MIN_RATE, &id, &rate);
}

static inline int pc_clk_set_max_rate(unsigned id, unsigned rate)
{
      return msm_proc_comm(PCOM_CLKCTL_RPC_MAX_RATE, &id, &rate);
}

static inline int pc_clk_set_flags(unsigned id, unsigned flags)
{
      return msm_proc_comm(PCOM_CLKCTL_RPC_SET_FLAGS, &id, &flags);
}

static inline unsigned pc_clk_get_rate(unsigned id)
{
      if (msm_proc_comm(PCOM_CLKCTL_RPC_RATE, &id, NULL))
            return 0;
      else
            return id;
}

static inline unsigned pc_clk_is_enabled(unsigned id)
{
      if (msm_proc_comm(PCOM_CLKCTL_RPC_ENABLED, &id, NULL))
            return 0;
      else
            return id;
}

static inline int pc_pll_request(unsigned id, unsigned on)
{
      on = !!on;
      return msm_proc_comm(PCOM_CLKCTL_RPC_PLL_REQUEST, &id, &on);
}

/*
 * Standard clock functions defined in include/linux/clk.h
 */
struct clk *clk_get(struct device *dev, const char *id)
{
      struct clk *clk;

      mutex_lock(&clocks_mutex);

      list_for_each_entry(clk, &clocks, list)
            if (!strcmp(id, clk->name) && clk->dev == dev)
                  goto found_it;

      list_for_each_entry(clk, &clocks, list)
            if (!strcmp(id, clk->name) && clk->dev == NULL)
                  goto found_it;

      clk = ERR_PTR(-ENOENT);
found_it:
      mutex_unlock(&clocks_mutex);
      return clk;
}
EXPORT_SYMBOL(clk_get);

void clk_put(struct clk *clk)
{
}
EXPORT_SYMBOL(clk_put);

int clk_enable(struct clk *clk)
{
      unsigned long flags;
      spin_lock_irqsave(&clocks_lock, flags);
      clk->count++;
      if (clk->count == 1)
            pc_clk_enable(clk->id);
      spin_unlock_irqrestore(&clocks_lock, flags);
      return 0;
}
EXPORT_SYMBOL(clk_enable);

void clk_disable(struct clk *clk)
{
      unsigned long flags;
      spin_lock_irqsave(&clocks_lock, flags);
      BUG_ON(clk->count == 0);
      clk->count--;
      if (clk->count == 0)
            pc_clk_disable(clk->id);
      spin_unlock_irqrestore(&clocks_lock, flags);
}
EXPORT_SYMBOL(clk_disable);

unsigned long clk_get_rate(struct clk *clk)
{
      return pc_clk_get_rate(clk->id);
}
EXPORT_SYMBOL(clk_get_rate);

int clk_set_rate(struct clk *clk, unsigned long rate)
{
      int ret;
      if (clk->flags & CLKFLAG_USE_MIN_MAX_TO_SET) {
            ret = pc_clk_set_max_rate(clk->id, rate);
            if (ret)
                  return ret;
            return pc_clk_set_min_rate(clk->id, rate);
      }
      return pc_clk_set_rate(clk->id, rate);
}
EXPORT_SYMBOL(clk_set_rate);

int clk_set_parent(struct clk *clk, struct clk *parent)
{
      return -ENOSYS;
}
EXPORT_SYMBOL(clk_set_parent);

struct clk *clk_get_parent(struct clk *clk)
{
      return ERR_PTR(-ENOSYS);
}
EXPORT_SYMBOL(clk_get_parent);

int clk_set_flags(struct clk *clk, unsigned long flags)
{
      if (clk == NULL || IS_ERR(clk))
            return -EINVAL;
      return pc_clk_set_flags(clk->id, flags);
}
EXPORT_SYMBOL(clk_set_flags);


void __init msm_clock_init(void)
{
      unsigned n;

      spin_lock_init(&clocks_lock);
      mutex_lock(&clocks_mutex);
      for (n = 0; n < msm_num_clocks; n++)
            list_add_tail(&msm_clocks[n].list, &clocks);
      mutex_unlock(&clocks_mutex);
}

/* The bootloader and/or AMSS may have left various clocks enabled.
 * Disable any clocks that belong to us (CLKFLAG_AUTO_OFF) but have
 * not been explicitly enabled by a clk_enable() call.
 */
static int __init clock_late_init(void)
{
      unsigned long flags;
      struct clk *clk;
      unsigned count = 0;

      mutex_lock(&clocks_mutex);
      list_for_each_entry(clk, &clocks, list) {
            if (clk->flags & CLKFLAG_AUTO_OFF) {
                  spin_lock_irqsave(&clocks_lock, flags);
                  if (!clk->count) {
                        count++;
                        pc_clk_disable(clk->id);
                  }
                  spin_unlock_irqrestore(&clocks_lock, flags);
            }
      }
      mutex_unlock(&clocks_mutex);
      pr_info("clock_late_init() disabled %d unused clocks\n", count);
      return 0;
}

late_initcall(clock_late_init);

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