linux/drivers/cpufreq/imx6q-cpufreq.c

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/*
* Copyright (C) 2013 Freescale Semiconductor, 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.
*/
#include <linux/clk.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/opp.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
#define PU_SOC_VOLTAGE_NORMAL 1250000
#define PU_SOC_VOLTAGE_HIGH 1275000
#define FREQ_1P2_GHZ 1200000000
static struct regulator *arm_reg;
static struct regulator *pu_reg;
static struct regulator *soc_reg;
static struct clk *arm_clk;
static struct clk *pll1_sys_clk;
static struct clk *pll1_sw_clk;
static struct clk *step_clk;
static struct clk *pll2_pfd2_396m_clk;
static struct device *cpu_dev;
static struct cpufreq_frequency_table *freq_table;
static unsigned int transition_latency;
static int imx6q_verify_speed(struct cpufreq_policy *policy)
{
return cpufreq_frequency_table_verify(policy, freq_table);
}
static unsigned int imx6q_get_speed(unsigned int cpu)
{
return clk_get_rate(arm_clk) / 1000;
}
static int imx6q_set_target(struct cpufreq_policy *policy,
unsigned int target_freq, unsigned int relation)
{
struct cpufreq_freqs freqs;
struct opp *opp;
unsigned long freq_hz, volt, volt_old;
unsigned int index;
int ret;
ret = cpufreq_frequency_table_target(policy, freq_table, target_freq,
relation, &index);
if (ret) {
dev_err(cpu_dev, "failed to match target frequency %d: %d\n",
target_freq, ret);
return ret;
}
freqs.new = freq_table[index].frequency;
freq_hz = freqs.new * 1000;
freqs.old = clk_get_rate(arm_clk) / 1000;
if (freqs.old == freqs.new)
return 0;
cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
rcu_read_lock();
opp = 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 = opp_get_voltage(opp);
rcu_read_unlock();
volt_old = regulator_get_voltage(arm_reg);
dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n",
freqs.old / 1000, volt_old / 1000,
freqs.new / 1000, volt / 1000);
/* scaling up? scale voltage before frequency */
if (freqs.new > freqs.old) {
ret = regulator_set_voltage_tol(arm_reg, volt, 0);
if (ret) {
dev_err(cpu_dev,
"failed to scale vddarm up: %d\n", ret);
return ret;
}
/*
* Need to increase vddpu and vddsoc for safety
* if we are about to run at 1.2 GHz.
*/
if (freqs.new == FREQ_1P2_GHZ / 1000) {
regulator_set_voltage_tol(pu_reg,
PU_SOC_VOLTAGE_HIGH, 0);
regulator_set_voltage_tol(soc_reg,
PU_SOC_VOLTAGE_HIGH, 0);
}
}
/*
* The setpoints are selected per PLL/PDF frequencies, so we need to
* reprogram PLL for frequency scaling. The procedure of reprogramming
* PLL1 is as below.
*
* - Enable pll2_pfd2_396m_clk and reparent pll1_sw_clk to it
* - Reprogram pll1_sys_clk and reparent pll1_sw_clk back to it
* - Disable pll2_pfd2_396m_clk
*/
clk_prepare_enable(pll2_pfd2_396m_clk);
clk_set_parent(step_clk, pll2_pfd2_396m_clk);
clk_set_parent(pll1_sw_clk, step_clk);
if (freq_hz > clk_get_rate(pll2_pfd2_396m_clk)) {
clk_set_rate(pll1_sys_clk, freqs.new * 1000);
/*
* If we are leaving 396 MHz set-point, we need to enable
* pll1_sys_clk and disable pll2_pfd2_396m_clk to keep
* their use count correct.
*/
if (freqs.old * 1000 <= clk_get_rate(pll2_pfd2_396m_clk)) {
clk_prepare_enable(pll1_sys_clk);
clk_disable_unprepare(pll2_pfd2_396m_clk);
}
clk_set_parent(pll1_sw_clk, pll1_sys_clk);
clk_disable_unprepare(pll2_pfd2_396m_clk);
} else {
/*
* Disable pll1_sys_clk if pll2_pfd2_396m_clk is sufficient
* to provide the frequency.
*/
clk_disable_unprepare(pll1_sys_clk);
}
/* Ensure the arm clock divider is what we expect */
ret = clk_set_rate(arm_clk, freqs.new * 1000);
if (ret) {
dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
regulator_set_voltage_tol(arm_reg, volt_old, 0);
return ret;
}
/* scaling down? scale voltage after frequency */
if (freqs.new < freqs.old) {
ret = regulator_set_voltage_tol(arm_reg, volt, 0);
if (ret)
dev_warn(cpu_dev,
"failed to scale vddarm down: %d\n", ret);
if (freqs.old == FREQ_1P2_GHZ / 1000) {
regulator_set_voltage_tol(pu_reg,
PU_SOC_VOLTAGE_NORMAL, 0);
regulator_set_voltage_tol(soc_reg,
PU_SOC_VOLTAGE_NORMAL, 0);
}
}
cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
return 0;
}
static int imx6q_cpufreq_init(struct cpufreq_policy *policy)
{
int ret;
ret = cpufreq_frequency_table_cpuinfo(policy, freq_table);
if (ret) {
dev_err(cpu_dev, "invalid frequency table: %d\n", ret);
return ret;
}
policy->cpuinfo.transition_latency = transition_latency;
policy->cur = clk_get_rate(arm_clk) / 1000;
cpumask_setall(policy->cpus);
cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
return 0;
}
static int imx6q_cpufreq_exit(struct cpufreq_policy *policy)
{
cpufreq_frequency_table_put_attr(policy->cpu);
return 0;
}
static struct freq_attr *imx6q_cpufreq_attr[] = {
&cpufreq_freq_attr_scaling_available_freqs,
NULL,
};
static struct cpufreq_driver imx6q_cpufreq_driver = {
.verify = imx6q_verify_speed,
.target = imx6q_set_target,
.get = imx6q_get_speed,
.init = imx6q_cpufreq_init,
.exit = imx6q_cpufreq_exit,
.name = "imx6q-cpufreq",
.attr = imx6q_cpufreq_attr,
};
static int imx6q_cpufreq_probe(struct platform_device *pdev)
{
struct device_node *np;
struct opp *opp;
unsigned long min_volt, max_volt;
int num, ret;
cpu_dev = &pdev->dev;
np = of_find_node_by_path("/cpus/cpu@0");
if (!np) {
dev_err(cpu_dev, "failed to find cpu0 node\n");
return -ENOENT;
}
cpu_dev->of_node = np;
arm_clk = devm_clk_get(cpu_dev, "arm");
pll1_sys_clk = devm_clk_get(cpu_dev, "pll1_sys");
pll1_sw_clk = devm_clk_get(cpu_dev, "pll1_sw");
step_clk = devm_clk_get(cpu_dev, "step");
pll2_pfd2_396m_clk = devm_clk_get(cpu_dev, "pll2_pfd2_396m");
if (IS_ERR(arm_clk) || IS_ERR(pll1_sys_clk) || IS_ERR(pll1_sw_clk) ||
IS_ERR(step_clk) || IS_ERR(pll2_pfd2_396m_clk)) {
dev_err(cpu_dev, "failed to get clocks\n");
ret = -ENOENT;
goto put_node;
}
arm_reg = devm_regulator_get(cpu_dev, "arm");
pu_reg = devm_regulator_get(cpu_dev, "pu");
soc_reg = devm_regulator_get(cpu_dev, "soc");
if (IS_ERR(arm_reg) || IS_ERR(pu_reg) || IS_ERR(soc_reg)) {
dev_err(cpu_dev, "failed to get regulators\n");
ret = -ENOENT;
goto put_node;
}
/* We expect an OPP table supplied by platform */
num = opp_get_opp_count(cpu_dev);
if (num < 0) {
ret = num;
dev_err(cpu_dev, "no OPP table is found: %d\n", ret);
goto put_node;
}
ret = opp_init_cpufreq_table(cpu_dev, &freq_table);
if (ret) {
dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
goto put_node;
}
if (of_property_read_u32(np, "clock-latency", &transition_latency))
transition_latency = CPUFREQ_ETERNAL;
/*
* OPP is maintained in order of increasing frequency, and
* freq_table initialised from OPP is therefore sorted in the
* same order.
*/
rcu_read_lock();
opp = opp_find_freq_exact(cpu_dev,
freq_table[0].frequency * 1000, true);
min_volt = opp_get_voltage(opp);
opp = opp_find_freq_exact(cpu_dev,
freq_table[--num].frequency * 1000, true);
max_volt = opp_get_voltage(opp);
rcu_read_unlock();
ret = regulator_set_voltage_time(arm_reg, min_volt, max_volt);
if (ret > 0)
transition_latency += ret * 1000;
/* Count vddpu and vddsoc latency in for 1.2 GHz support */
if (freq_table[num].frequency == FREQ_1P2_GHZ / 1000) {
ret = regulator_set_voltage_time(pu_reg, PU_SOC_VOLTAGE_NORMAL,
PU_SOC_VOLTAGE_HIGH);
if (ret > 0)
transition_latency += ret * 1000;
ret = regulator_set_voltage_time(soc_reg, PU_SOC_VOLTAGE_NORMAL,
PU_SOC_VOLTAGE_HIGH);
if (ret > 0)
transition_latency += ret * 1000;
}
ret = cpufreq_register_driver(&imx6q_cpufreq_driver);
if (ret) {
dev_err(cpu_dev, "failed register driver: %d\n", ret);
goto free_freq_table;
}
of_node_put(np);
return 0;
free_freq_table:
opp_free_cpufreq_table(cpu_dev, &freq_table);
put_node:
of_node_put(np);
return ret;
}
static int imx6q_cpufreq_remove(struct platform_device *pdev)
{
cpufreq_unregister_driver(&imx6q_cpufreq_driver);
opp_free_cpufreq_table(cpu_dev, &freq_table);
return 0;
}
static struct platform_driver imx6q_cpufreq_platdrv = {
.driver = {
.name = "imx6q-cpufreq",
.owner = THIS_MODULE,
},
.probe = imx6q_cpufreq_probe,
.remove = imx6q_cpufreq_remove,
};
module_platform_driver(imx6q_cpufreq_platdrv);
MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
MODULE_DESCRIPTION("Freescale i.MX6Q cpufreq driver");
MODULE_LICENSE("GPL");