linux-imx

/*

 * Copyright (C) 2012 Calxeda, Inc.

 *

 * 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.

 *

 * This driver provides the clk notifier callbacks that are used when

 * the cpufreq-dt driver changes to frequency to alert the highbank

 * EnergyCore Management Engine (ECME) about the need to change

 * voltage. The ECME interfaces with the actual voltage regulators.

 */

​

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

​

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/clk.h>

#include <linux/cpu.h>

#include <linux/err.h>

#include <linux/of.h>

#include <linux/pl320-ipc.h>

#include <linux/platform_device.h>

​

#define HB_CPUFREQ_CHANGE_NOTE  0x80000001

#define HB_CPUFREQ_IPC_LEN  7

#define HB_CPUFREQ_VOLT_RETRIES 15

​

static int hb_voltage_change(unsigned int freq)

{

    u32 msg[HB_CPUFREQ_IPC_LEN] = {HB_CPUFREQ_CHANGE_NOTE, freq / 1000000};

​

    return pl320_ipc_transmit(msg);

}

​

static int hb_cpufreq_clk_notify(struct notifier_block *nb,

                unsigned long action, void *hclk)

{

    struct clk_notifier_data *clk_data = hclk;

    int i = 0;

​

    if (action == PRE_RATE_CHANGE) {

        if (clk_data->new_rate > clk_data->old_rate)

            while (hb_voltage_change(clk_data->new_rate))

                if (i++ > HB_CPUFREQ_VOLT_RETRIES)

                    return NOTIFY_BAD;

    } else if (action == POST_RATE_CHANGE) {

        if (clk_data->new_rate < clk_data->old_rate)

            while (hb_voltage_change(clk_data->new_rate))

                if (i++ > HB_CPUFREQ_VOLT_RETRIES)

                    return NOTIFY_BAD;

    }

​

    return NOTIFY_DONE;

}

​

static struct notifier_block hb_cpufreq_clk_nb = {

    .notifier_call = hb_cpufreq_clk_notify,

};

​

static int hb_cpufreq_driver_init(void)

{

    struct platform_device_info devinfo = { .name = "cpufreq-dt", };