linux-imx

/*

 *  CPU frequency scaling for OMAP using OPP information

 *

 *  Copyright (C) 2005 Nokia Corporation

 *  Written by Tony Lindgren <tony@atomide.com>

 *

 *  Based on cpu-sa1110.c, Copyright (C) 2001 Russell King

 *

 * Copyright (C) 2007-2011 Texas Instruments, Inc.

 * - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 */

​

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

​

#include <linux/types.h>

#include <linux/kernel.h>

#include <linux/sched.h>

#include <linux/cpufreq.h>

#include <linux/delay.h>

#include <linux/init.h>

#include <linux/err.h>

#include <linux/clk.h>

#include <linux/io.h>

#include <linux/pm_opp.h>

#include <linux/cpu.h>

#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/regulator/consumer.h>

​

#include <asm/smp_plat.h>

#include <asm/cpu.h>

​

/* OPP tolerance in percentage */

#define OPP_TOLERANCE   4

​

static struct cpufreq_frequency_table *freq_table;

static atomic_t freq_table_users = ATOMIC_INIT(0);

static struct device *mpu_dev;

static struct regulator *mpu_reg;

​

static int omap_target(struct cpufreq_policy *policy, unsigned int index)

{

    int r, ret;

    struct dev_pm_opp *opp;

    unsigned long freq, volt = 0, volt_old = 0, tol = 0;

    unsigned int old_freq, new_freq;

​

    old_freq = policy->cur;

    new_freq = freq_table[index].frequency;

​

    freq = new_freq * 1000;

    ret = clk_round_rate(policy->clk, freq);

    if (ret < 0) {

        dev_warn(mpu_dev,

             "CPUfreq: Cannot find matching frequency for %lu\n",

             freq);

        return ret;

    }

    freq = ret;

​

    if (mpu_reg) {

        opp = dev_pm_opp_find_freq_ceil(mpu_dev, &freq);

        if (IS_ERR(opp)) {

            dev_err(mpu_dev, "%s: unable to find MPU OPP for %d\n",

                __func__, new_freq);

            return -EINVAL;

        }

        volt = dev_pm_opp_get_voltage(opp);

        dev_pm_opp_put(opp);

        tol = volt * OPP_TOLERANCE / 100;

        volt_old = regulator_get_voltage(mpu_reg);

    }

​

    dev_dbg(mpu_dev, "cpufreq-omap: %u MHz, %ld mV --> %u MHz, %ld mV\n", 

        old_freq / 1000, volt_old ? volt_old / 1000 : -1,

        new_freq / 1000, volt ? volt / 1000 : -1);

​

    /* scaling up?  scale voltage before frequency */

    if (mpu_reg && (new_freq > old_freq)) {

        r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);

        if (r < 0) {

            dev_warn(mpu_dev, "%s: unable to scale voltage up.\n",

                 __func__);

            return r;

        }

    }

​

    ret = clk_set_rate(policy->clk, new_freq * 1000);