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pm.c

/*
 *  Copyright 2008-2009 Freescale Semiconductor, Inc. All Rights Reserved.
 */

/*
 * The code contained herein is licensed under the GNU General Public
 * License. You may obtain a copy of the GNU General Public License
 * Version 2 or later at the following locations:
 *
 * http://www.opensource.org/licenses/gpl-license.html
 * http://www.gnu.org/copyleft/gpl.html
 */

#include <linux/proc_fs.h>
#include <linux/kernel.h>
#include <linux/suspend.h>
#include <linux/clk.h>
#include <linux/cpufreq.h>
#include <mach/hardware.h>

static struct cpu_wp *cpu_wp_tbl;
static struct clk *cpu_clk;

#if defined(CONFIG_CPU_FREQ)
static int org_freq;
extern int cpufreq_suspended;
extern int set_cpu_freq(int wp);
#endif

static int mx37_suspend_enter(suspend_state_t state)
{
      switch (state) {
      case PM_SUSPEND_MEM:
            mxc_cpu_lp_set(STOP_POWER_OFF);
            break;
      case PM_SUSPEND_STANDBY:
            mxc_cpu_lp_set(WAIT_UNCLOCKED_POWER_OFF);
            break;
      default:
            return -EINVAL;
      }

      if (tzic_enable_wake(0) != 0)
            return -EAGAIN;

      cpu_do_idle();

      return 0;
}

/*
 * Called after processes are frozen, but before we shut down devices.
 */
static int mx37_suspend_prepare(void)
{
#if defined(CONFIG_CPU_FREQ)
      struct cpufreq_freqs freqs;
      org_freq = clk_get_rate(cpu_clk);
      freqs.old = org_freq / 1000;
      freqs.new = cpu_wp_tbl[0].cpu_rate / 1000;
      freqs.cpu = 0;
      freqs.flags = 0;

      cpufreq_suspended = 1;
      if (clk_get_rate(cpu_clk) != cpu_wp_tbl[0].cpu_rate) {
            set_cpu_freq(cpu_wp_tbl[0].cpu_rate);
            cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
            cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
      }
#endif
      return 0;
}

/*
 * Called after devices are re-setup, but before processes are thawed.
 */
static void mx37_suspend_finish(void)
{
#if defined(CONFIG_CPU_FREQ)
      struct cpufreq_freqs freqs;

      freqs.old = clk_get_rate(cpu_clk) / 1000;
      freqs.new = org_freq / 1000;
      freqs.cpu = 0;
      freqs.flags = 0;

      cpufreq_suspended = 0;

      if (org_freq != clk_get_rate(cpu_clk)) {
            set_cpu_freq(org_freq);
            cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
            cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
      }
#endif
}

static int mx37_pm_valid(suspend_state_t state)
{
      return (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX);
}

struct platform_suspend_ops mx37_suspend_ops = {
      .valid = mx37_pm_valid,
      .prepare = mx37_suspend_prepare,
      .enter = mx37_suspend_enter,
      .finish = mx37_suspend_finish,
};

static int __init mx37_pm_init(void)
{
      int cpu_wp_nr;

      pr_info("Static Power Management for Freescale i.MX37\n");
      suspend_set_ops(&mx37_suspend_ops);

      cpu_wp_tbl = get_cpu_wp(&cpu_wp_nr);

      cpu_clk = clk_get(NULL, "cpu_clk");
      if (IS_ERR(cpu_clk)) {
            printk(KERN_DEBUG "%s: failed to get cpu_clk\n", __func__);
            return PTR_ERR(cpu_clk);
      }
      return 0;
}

late_initcall(mx37_pm_init);

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