/* * CPU frequency scaling for OMAP using OPP information * * Copyright (C) 2005 Nokia Corporation * Written by Tony Lindgren <tony@atomide.com> * * Based on cpu-sa1110.c, Copyright (C) 2001 Russell King * * Copyright (C) 2007-2011 Texas Instruments, Inc. * - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar * * 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/types.h> #include <linux/kernel.h> #include <linux/sched.h> #include <linux/cpufreq.h> #include <linux/delay.h> #include <linux/init.h> #include <linux/err.h> #include <linux/clk.h> #include <linux/io.h> #include <linux/pm_opp.h> #include <linux/cpu.h> #include <linux/module.h> #include <linux/platform_device.h> #include <linux/regulator/consumer.h> #include <asm/smp_plat.h> #include <asm/cpu.h> /* OPP tolerance in percentage */ #define OPP_TOLERANCE 4 static struct cpufreq_frequency_table *freq_table; static atomic_t freq_table_users = ATOMIC_INIT(0); static struct device *mpu_dev; static struct regulator *mpu_reg; static int omap_target(struct cpufreq_policy *policy, unsigned int index) { int r, ret; struct dev_pm_opp *opp; unsigned long freq, volt = 0, volt_old = 0, tol = 0; unsigned int old_freq, new_freq; old_freq = policy->cur; new_freq = freq_table[index].frequency; freq = new_freq * 1000; ret = clk_round_rate(policy->clk, freq); if (IS_ERR_VALUE(ret)) { dev_warn(mpu_dev, "CPUfreq: Cannot find matching frequency for %lu\n", freq); return ret; } freq = ret; if (mpu_reg) { rcu_read_lock(); opp = dev_pm_opp_find_freq_ceil(mpu_dev, &freq); if (IS_ERR(opp)) { rcu_read_unlock(); dev_err(mpu_dev, "%s: unable to find MPU OPP for %d\n", __func__, new_freq); return -EINVAL; } volt = dev_pm_opp_get_voltage(opp); rcu_read_unlock(); tol = volt * OPP_TOLERANCE / 100; volt_old = regulator_get_voltage(mpu_reg); } dev_dbg(mpu_dev, "cpufreq-omap: %u MHz, %ld mV --> %u MHz, %ld mV\n", old_freq / 1000, volt_old ? volt_old / 1000 : -1, new_freq / 1000, volt ? volt / 1000 : -1); /* scaling up? scale voltage before frequency */ if (mpu_reg && (new_freq > old_freq)) { r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol); if (r < 0) { dev_warn(mpu_dev, "%s: unable to scale voltage up.\n", __func__); return r; } } ret = clk_set_rate(policy->clk, new_freq * 1000); /* scaling down? scale voltage after frequency */ if (mpu_reg && (new_freq < old_freq)) { r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol); if (r < 0) { dev_warn(mpu_dev, "%s: unable to scale voltage down.\n", __func__); clk_set_rate(policy->clk, old_freq * 1000); return r; } } return ret; } static inline void freq_table_free(void) { if (atomic_dec_and_test(&freq_table_users)) dev_pm_opp_free_cpufreq_table(mpu_dev, &freq_table); } static int omap_cpu_init(struct cpufreq_policy *policy) { int result; policy->clk = clk_get(NULL, "cpufreq_ck"); if (IS_ERR(policy->clk)) return PTR_ERR(policy->clk); if (!freq_table) { result = dev_pm_opp_init_cpufreq_table(mpu_dev, &freq_table); if (result) { dev_err(mpu_dev, "%s: cpu%d: failed creating freq table[%d]\n", __func__, policy->cpu, result); goto fail; } } atomic_inc_return(&freq_table_users); /* FIXME: what's the actual transition time? */ result = cpufreq_generic_init(policy, freq_table, 300 * 1000); if (!result) return 0; freq_table_free(); fail: clk_put(policy->clk); return result; } static int omap_cpu_exit(struct cpufreq_policy *policy) { freq_table_free(); clk_put(policy->clk); return 0; } static struct cpufreq_driver omap_driver = { .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK, .verify = cpufreq_generic_frequency_table_verify, .target_index = omap_target, .get = cpufreq_generic_get, .init = omap_cpu_init, .exit = omap_cpu_exit, .name = "omap", .attr = cpufreq_generic_attr, }; static int omap_cpufreq_probe(struct platform_device *pdev) { mpu_dev = get_cpu_device(0); if (!mpu_dev) { pr_warning("%s: unable to get the mpu device\n", __func__); return -EINVAL; } mpu_reg = regulator_get(mpu_dev, "vcc"); if (IS_ERR(mpu_reg)) { pr_warning("%s: unable to get MPU regulator\n", __func__); mpu_reg = NULL; } else { /* * Ensure physical regulator is present. * (e.g. could be dummy regulator.) */ if (regulator_get_voltage(mpu_reg) < 0) { pr_warn("%s: physical regulator not present for MPU\n", __func__); regulator_put(mpu_reg); mpu_reg = NULL; } } return cpufreq_register_driver(&omap_driver); } static int omap_cpufreq_remove(struct platform_device *pdev) { return cpufreq_unregister_driver(&omap_driver); } static struct platform_driver omap_cpufreq_platdrv = { .driver = { .name = "omap-cpufreq", }, .probe = omap_cpufreq_probe, .remove = omap_cpufreq_remove, }; module_platform_driver(omap_cpufreq_platdrv); MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs"); MODULE_LICENSE("GPL");