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/*
* Generic Exynos Bus frequency driver with DEVFREQ Framework
*
* Copyright (c) 2016 Samsung Electronics Co., Ltd.
* Author : Chanwoo Choi <cw00.choi@samsung.com>
*
* This driver support Exynos Bus frequency feature by using
* DEVFREQ framework and is based on drivers/devfreq/exynos/exynos4_bus.c.
*
* 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.
*/
#include <linux/clk.h>
#include <linux/devfreq.h>
#include <linux/devfreq-event.h>
#include <linux/device.h>
#include <linux/export.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/pm_opp.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#define DEFAULT_SATURATION_RATIO 40
#define DEFAULT_VOLTAGE_TOLERANCE 2
struct exynos_bus {
struct device *dev;
struct devfreq *devfreq;
struct devfreq_event_dev **edev;
unsigned int edev_count;
struct mutex lock;
unsigned long curr_freq;
struct regulator *regulator;
struct clk *clk;
unsigned int voltage_tolerance;
unsigned int ratio;
};
/*
* Control the devfreq-event device to get the current state of bus
*/
#define exynos_bus_ops_edev(ops) \
static int exynos_bus_##ops(struct exynos_bus *bus) \
{ \
int i, ret; \
\
for (i = 0; i < bus->edev_count; i++) { \
if (!bus->edev[i]) \
continue; \
ret = devfreq_event_##ops(bus->edev[i]); \
if (ret < 0) \
return ret; \
} \
\
return 0; \
}
exynos_bus_ops_edev(enable_edev);
exynos_bus_ops_edev(disable_edev);
exynos_bus_ops_edev(set_event);
static int exynos_bus_get_event(struct exynos_bus *bus,
struct devfreq_event_data *edata)
{
struct devfreq_event_data event_data;
unsigned long load_count = 0, total_count = 0;
int i, ret = 0;
for (i = 0; i < bus->edev_count; i++) {
if (!bus->edev[i])
continue;
ret = devfreq_event_get_event(bus->edev[i], &event_data);
if (ret < 0)
return ret;
if (i == 0 || event_data.load_count > load_count) {
load_count = event_data.load_count;
total_count = event_data.total_count;
}
}
edata->load_count = load_count;
edata->total_count = total_count;
return ret;
}
/*
* Must necessary function for devfreq simple-ondemand governor
*/
static int exynos_bus_target(struct device *dev, unsigned long *freq, u32 flags)
{
struct exynos_bus *bus = dev_get_drvdata(dev);
struct dev_pm_opp *new_opp;
unsigned long old_freq, new_freq, new_volt, tol;
int ret = 0;
/* Get new opp-bus instance according to new bus clock */
new_opp = devfreq_recommended_opp(dev, freq, flags);
if (IS_ERR(new_opp)) {
dev_err(dev, "failed to get recommended opp instance\n");
return PTR_ERR(new_opp);
}
new_freq = dev_pm_opp_get_freq(new_opp);
new_volt = dev_pm_opp_get_voltage(new_opp);
dev_pm_opp_put(new_opp);
old_freq = bus->curr_freq;
if (old_freq == new_freq)
return 0;
tol = new_volt * bus->voltage_tolerance / 100;
/* Change voltage and frequency according to new OPP level */
mutex_lock(&bus->lock);
if (old_freq < new_freq) {
ret = regulator_set_voltage_tol(bus->regulator, new_volt, tol);
if (ret < 0) {
dev_err(bus->dev, "failed to set voltage\n");
goto out;
}
}
ret = clk_set_rate(bus->clk, new_freq);
if (ret < 0) {
dev_err(dev, "failed to change clock of bus\n");
clk_set_rate(bus->clk, old_freq);
goto out;
}
if (old_freq > new_freq) {
ret = regulator_set_voltage_tol(bus->regulator, new_volt, tol);
if (ret < 0) {
dev_err(bus->dev, "failed to set voltage\n");
goto out;
}
}
bus->curr_freq = new_freq;
dev_dbg(dev, "Set the frequency of bus (%luHz -> %luHz, %luHz)\n",
old_freq, new_freq, clk_get_rate(bus->clk));
out:
mutex_unlock(&bus->lock);
return ret;
}
static int exynos_bus_get_dev_status(struct device *dev,
struct devfreq_dev_status *stat)
{
struct exynos_bus *bus = dev_get_drvdata(dev);
struct devfreq_event_data edata;
int ret;
stat->current_frequency = bus->curr_freq;
ret = exynos_bus_get_event(bus, &edata);
if (ret < 0) {
stat->total_time = stat->busy_time = 0;
goto err;
}
stat->busy_time = (edata.load_count * 100) / bus->ratio;
stat->total_time = edata.total_count;
dev_dbg(dev, "Usage of devfreq-event : %lu/%lu\n", stat->busy_time,
stat->total_time);
err:
ret = exynos_bus_set_event(bus);
if (ret < 0) {
dev_err(dev, "failed to set event to devfreq-event devices\n");
return ret;
}
return ret;
}
static void exynos_bus_exit(struct device *dev)
{
struct exynos_bus *bus = dev_get_drvdata(dev);
int ret;
ret = exynos_bus_disable_edev(bus);
if (ret < 0)
dev_warn(dev, "failed to disable the devfreq-event devices\n");
if (bus->regulator)
regulator_disable(bus->regulator);
dev_pm_opp_of_remove_table(dev);
clk_disable_unprepare(bus->clk);
}
/*
* Must necessary function for devfreq passive governor
*/
static int exynos_bus_passive_target(struct device *dev, unsigned long *freq,
u32 flags)
{
struct exynos_bus *bus = dev_get_drvdata(dev);
struct dev_pm_opp *new_opp;
unsigned long old_freq, new_freq;
int ret = 0;
/* Get new opp-bus instance according to new bus clock */
new_opp = devfreq_recommended_opp(dev, freq, flags);
if (IS_ERR(new_opp)) {
dev_err(dev, "failed to get recommended opp instance\n");
return PTR_ERR(new_opp);
}
new_freq = dev_pm_opp_get_freq(new_opp);
dev_pm_opp_put(new_opp);
old_freq = bus->curr_freq;
if (old_freq == new_freq)
return 0;
/* Change the frequency according to new OPP level */
mutex_lock(&bus->lock);
ret = clk_set_rate(bus->clk, new_freq);
if (ret < 0) {
dev_err(dev, "failed to set the clock of bus\n");
goto out;
}
*freq = new_freq;
bus->curr_freq = new_freq;
dev_dbg(dev, "Set the frequency of bus (%luHz -> %luHz, %luHz)\n",
old_freq, new_freq, clk_get_rate(bus->clk));
out:
mutex_unlock(&bus->lock);
return ret;
}
static void
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