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/*
* Copyright (C) 2012 Freescale Semiconductor, Inc.
*
* Copyright (C) 2014 Linaro.
* Viresh Kumar <viresh.kumar@linaro.org>
*
* The OPP code in function set_target() is reused from
* drivers/cpufreq/omap-cpufreq.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.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/clk.h>
#include <linux/cpu.h>
#include <linux/cpu_cooling.h>
#include <linux/cpufreq.h>
#include <linux/cpufreq-dt.h>
#include <linux/cpumask.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/pm_opp.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include <linux/thermal.h>
struct private_data {
struct device *cpu_dev;
struct regulator *cpu_reg;
struct thermal_cooling_device *cdev;
unsigned int voltage_tolerance; /* in percentage */
};
static int set_target(struct cpufreq_policy *policy, unsigned int index)
{
struct dev_pm_opp *opp;
struct cpufreq_frequency_table *freq_table = policy->freq_table;
struct clk *cpu_clk = policy->clk;
struct private_data *priv = policy->driver_data;
struct device *cpu_dev = priv->cpu_dev;
struct regulator *cpu_reg = priv->cpu_reg;
unsigned long volt = 0, volt_old = 0, tol = 0;
unsigned int old_freq, new_freq;
long freq_Hz, freq_exact;
int ret;
freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
if (freq_Hz <= 0)
freq_Hz = freq_table[index].frequency * 1000;
freq_exact = freq_Hz;
new_freq = freq_Hz / 1000;
old_freq = clk_get_rate(cpu_clk) / 1000;
if (!IS_ERR(cpu_reg)) {
unsigned long opp_freq;
rcu_read_lock();
opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_Hz);
if (IS_ERR(opp)) {
rcu_read_unlock();
dev_err(cpu_dev, "failed to find OPP for %ld\n",
freq_Hz);
return PTR_ERR(opp);
}
volt = dev_pm_opp_get_voltage(opp);
opp_freq = dev_pm_opp_get_freq(opp);
rcu_read_unlock();
tol = volt * priv->voltage_tolerance / 100;
volt_old = regulator_get_voltage(cpu_reg);
dev_dbg(cpu_dev, "Found OPP: %ld kHz, %ld uV\n",
opp_freq / 1000, volt);
}
dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n",
old_freq / 1000, (volt_old > 0) ? volt_old / 1000 : -1,
new_freq / 1000, volt ? volt / 1000 : -1);
/* scaling up? scale voltage before frequency */
if (!IS_ERR(cpu_reg) && new_freq > old_freq) {
ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
if (ret) {
dev_err(cpu_dev, "failed to scale voltage up: %d\n",
ret);
return ret;
}
}
ret = clk_set_rate(cpu_clk, freq_exact);
if (ret) {
dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
if (!IS_ERR(cpu_reg) && volt_old > 0)
regulator_set_voltage_tol(cpu_reg, volt_old, tol);
return ret;
}
/* scaling down? scale voltage after frequency */
if (!IS_ERR(cpu_reg) && new_freq < old_freq) {
ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
if (ret) {
dev_err(cpu_dev, "failed to scale voltage down: %d\n",
ret);
clk_set_rate(cpu_clk, old_freq * 1000);
}
}
return ret;
}
static int allocate_resources(int cpu, struct device **cdev,
struct regulator **creg, struct clk **cclk)
{
struct device *cpu_dev;
struct regulator *cpu_reg;
struct clk *cpu_clk;
int ret = 0;
char *reg_cpu0 = "cpu0", *reg_cpu = "cpu", *reg;
cpu_dev = get_cpu_device(cpu);
if (!cpu_dev) {
pr_err("failed to get cpu%d device\n", cpu);
return -ENODEV;
}
/* Try "cpu0" for older DTs */
if (!cpu)
reg = reg_cpu0;
else
reg = reg_cpu;
try_again:
cpu_reg = regulator_get_optional(cpu_dev, reg);
if (IS_ERR(cpu_reg)) {
/*
* If cpu's regulator supply node is present, but regulator is
* not yet registered, we should try defering probe.
*/
if (PTR_ERR(cpu_reg) == -EPROBE_DEFER) {
dev_dbg(cpu_dev, "cpu%d regulator not ready, retry\n",
cpu);
return -EPROBE_DEFER;
}
/* Try with "cpu-supply" */
if (reg == reg_cpu0) {
reg = reg_cpu;
goto try_again;
}
dev_dbg(cpu_dev, "no regulator for cpu%d: %ld\n",
cpu, PTR_ERR(cpu_reg));
}
cpu_clk = clk_get(cpu_dev, NULL);
if (IS_ERR(cpu_clk)) {
/* put regulator */
if (!IS_ERR(cpu_reg))
regulator_put(cpu_reg);
ret = PTR_ERR(cpu_clk);
/*
* If cpu's clk node is present, but clock is not yet
* registered, we should try defering probe.
*/
if (ret == -EPROBE_DEFER)
dev_dbg(cpu_dev, "cpu%d clock not ready, retry\n", cpu);
else
dev_err(cpu_dev, "failed to get cpu%d clock: %d\n", cpu,
ret);
} else {
*cdev = cpu_dev;
*creg = cpu_reg;
*cclk = cpu_clk;
}
return ret;
}
static int cpufreq_init(struct cpufreq_policy *policy)
{
struct cpufreq_dt_platform_data *pd;
struct cpufreq_frequency_table *freq_table;
struct device_node *np;
struct private_data *priv;
struct device *cpu_dev;
struct regulator *cpu_reg;
struct clk *cpu_clk;
unsigned long min_uV = ~0, max_uV = 0;
unsigned int transition_latency;
int ret;
ret = allocate_resources(policy->cpu, &cpu_dev, &cpu_reg, &cpu_clk);
if (ret) {
pr_err("%s: Failed to allocate resources: %d\n", __func__, ret);
return ret;
}
np = of_node_get(cpu_dev->of_node);
if (!np) {
dev_err(cpu_dev, "failed to find cpu%d node\n", policy->cpu);
ret = -ENOENT;
goto out_put_reg_clk;
}
/* OPPs might be populated at runtime, don't check for error here */
of_init_opp_table(cpu_dev);
/*
* But we need OPP table to function so if it is not there let's
* give platform code chance to provide it for us.
*/
ret = dev_pm_opp_get_opp_count(cpu_dev);
if (ret <= 0) {
pr_debug("OPP table is not ready, deferring probe\n");
ret = -EPROBE_DEFER;
goto out_free_opp;
}
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv) {
ret = -ENOMEM;
goto out_free_opp;
}
of_property_read_u32(np, "voltage-tolerance", &priv->voltage_tolerance);
if (of_property_read_u32(np, "clock-latency", &transition_latency))
transition_latency = CPUFREQ_ETERNAL;
if (!IS_ERR(cpu_reg)) {
unsigned long opp_freq = 0;
/*
* Disable any OPPs where the connected regulator isn't able to
* provide the specified voltage and record minimum and maximum
* voltage levels.
*/
while (1) {
struct dev_pm_opp *opp;
unsigned long opp_uV, tol_uV;
rcu_read_lock();
opp = dev_pm_opp_find_freq_ceil(cpu_dev, &opp_freq);
if (IS_ERR(opp)) {
rcu_read_unlock();
break
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