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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * CPU frequency scaling for OMAP using OPP information4 *5 * Copyright (C) 2005 Nokia Corporation6 * Written by Tony Lindgren <tony@atomide.com>7 *8 * Based on cpu-sa1110.c, Copyright (C) 2001 Russell King9 *10 * Copyright (C) 2007-2011 Texas Instruments, Inc.11 * - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar12 */13 14#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt15 16#include <linux/types.h>17#include <linux/kernel.h>18#include <linux/sched.h>19#include <linux/cpufreq.h>20#include <linux/delay.h>21#include <linux/init.h>22#include <linux/err.h>23#include <linux/clk.h>24#include <linux/io.h>25#include <linux/pm_opp.h>26#include <linux/cpu.h>27#include <linux/module.h>28#include <linux/platform_device.h>29#include <linux/regulator/consumer.h>30 31/* OPP tolerance in percentage */32#define OPP_TOLERANCE 433 34static struct cpufreq_frequency_table *freq_table;35static atomic_t freq_table_users = ATOMIC_INIT(0);36static struct device *mpu_dev;37static struct regulator *mpu_reg;38 39static int omap_target(struct cpufreq_policy *policy, unsigned int index)40{41 int r, ret;42 struct dev_pm_opp *opp;43 unsigned long freq, volt = 0, volt_old = 0, tol = 0;44 unsigned int old_freq, new_freq;45 46 old_freq = policy->cur;47 new_freq = freq_table[index].frequency;48 49 freq = new_freq * 1000;50 ret = clk_round_rate(policy->clk, freq);51 if (ret < 0) {52 dev_warn(mpu_dev,53 "CPUfreq: Cannot find matching frequency for %lu\n",54 freq);55 return ret;56 }57 freq = ret;58 59 if (mpu_reg) {60 opp = dev_pm_opp_find_freq_ceil(mpu_dev, &freq);61 if (IS_ERR(opp)) {62 dev_err(mpu_dev, "%s: unable to find MPU OPP for %d\n",63 __func__, new_freq);64 return -EINVAL;65 }66 volt = dev_pm_opp_get_voltage(opp);67 dev_pm_opp_put(opp);68 tol = volt * OPP_TOLERANCE / 100;69 volt_old = regulator_get_voltage(mpu_reg);70 }71 72 dev_dbg(mpu_dev, "cpufreq-omap: %u MHz, %ld mV --> %u MHz, %ld mV\n", 73 old_freq / 1000, volt_old ? volt_old / 1000 : -1,74 new_freq / 1000, volt ? volt / 1000 : -1);75 76 /* scaling up? scale voltage before frequency */77 if (mpu_reg && (new_freq > old_freq)) {78 r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);79 if (r < 0) {80 dev_warn(mpu_dev, "%s: unable to scale voltage up.\n",81 __func__);82 return r;83 }84 }85 86 ret = clk_set_rate(policy->clk, new_freq * 1000);87 88 /* scaling down? scale voltage after frequency */89 if (mpu_reg && (new_freq < old_freq)) {90 r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);91 if (r < 0) {92 dev_warn(mpu_dev, "%s: unable to scale voltage down.\n",93 __func__);94 clk_set_rate(policy->clk, old_freq * 1000);95 return r;96 }97 }98 99 return ret;100}101 102static inline void freq_table_free(void)103{104 if (atomic_dec_and_test(&freq_table_users))105 dev_pm_opp_free_cpufreq_table(mpu_dev, &freq_table);106}107 108static int omap_cpu_init(struct cpufreq_policy *policy)109{110 int result;111 112 policy->clk = clk_get(NULL, "cpufreq_ck");113 if (IS_ERR(policy->clk))114 return PTR_ERR(policy->clk);115 116 if (!freq_table) {117 result = dev_pm_opp_init_cpufreq_table(mpu_dev, &freq_table);118 if (result) {119 dev_err(mpu_dev,120 "%s: cpu%d: failed creating freq table[%d]\n",121 __func__, policy->cpu, result);122 clk_put(policy->clk);123 return result;124 }125 }126 127 atomic_inc_return(&freq_table_users);128 129 /* FIXME: what's the actual transition time? */130 cpufreq_generic_init(policy, freq_table, 300 * 1000);131 132 return 0;133}134 135static void omap_cpu_exit(struct cpufreq_policy *policy)136{137 freq_table_free();138 clk_put(policy->clk);139}140 141static struct cpufreq_driver omap_driver = {142 .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,143 .verify = cpufreq_generic_frequency_table_verify,144 .target_index = omap_target,145 .get = cpufreq_generic_get,146 .init = omap_cpu_init,147 .exit = omap_cpu_exit,148 .register_em = cpufreq_register_em_with_opp,149 .name = "omap",150 .attr = cpufreq_generic_attr,151};152 153static int omap_cpufreq_probe(struct platform_device *pdev)154{155 mpu_dev = get_cpu_device(0);156 if (!mpu_dev) {157 pr_warn("%s: unable to get the MPU device\n", __func__);158 return -EINVAL;159 }160 161 mpu_reg = regulator_get(mpu_dev, "vcc");162 if (IS_ERR(mpu_reg)) {163 pr_warn("%s: unable to get MPU regulator\n", __func__);164 mpu_reg = NULL;165 } else {166 /* 167 * Ensure physical regulator is present.168 * (e.g. could be dummy regulator.)169 */170 if (regulator_get_voltage(mpu_reg) < 0) {171 pr_warn("%s: physical regulator not present for MPU\n",172 __func__);173 regulator_put(mpu_reg);174 mpu_reg = NULL;175 }176 }177 178 return cpufreq_register_driver(&omap_driver);179}180 181static void omap_cpufreq_remove(struct platform_device *pdev)182{183 cpufreq_unregister_driver(&omap_driver);184}185 186static struct platform_driver omap_cpufreq_platdrv = {187 .driver = {188 .name = "omap-cpufreq",189 },190 .probe = omap_cpufreq_probe,191 .remove_new = omap_cpufreq_remove,192};193module_platform_driver(omap_cpufreq_platdrv);194 195MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");196MODULE_LICENSE("GPL");197