292 lines
6.9 KiB
C
292 lines
6.9 KiB
C
/*
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* CPU frequency scaling for OMAP using OPP information
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*
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* Copyright (C) 2005 Nokia Corporation
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* Written by Tony Lindgren <tony@atomide.com>
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*
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* Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
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*
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* Copyright (C) 2007-2011 Texas Instruments, Inc.
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* - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/cpufreq.h>
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/err.h>
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#include <linux/clk.h>
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#include <linux/io.h>
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#include <linux/opp.h>
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#include <linux/cpu.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/regulator/consumer.h>
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#include <asm/smp_plat.h>
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#include <asm/cpu.h>
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/* OPP tolerance in percentage */
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#define OPP_TOLERANCE 4
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static struct cpufreq_frequency_table *freq_table;
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static atomic_t freq_table_users = ATOMIC_INIT(0);
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static struct clk *mpu_clk;
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static struct device *mpu_dev;
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static struct regulator *mpu_reg;
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static int omap_verify_speed(struct cpufreq_policy *policy)
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{
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if (!freq_table)
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return -EINVAL;
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return cpufreq_frequency_table_verify(policy, freq_table);
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}
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static unsigned int omap_getspeed(unsigned int cpu)
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{
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unsigned long rate;
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if (cpu >= NR_CPUS)
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return 0;
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rate = clk_get_rate(mpu_clk) / 1000;
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return rate;
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}
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static int omap_target(struct cpufreq_policy *policy,
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unsigned int target_freq,
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unsigned int relation)
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{
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unsigned int i;
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int r, ret = 0;
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struct cpufreq_freqs freqs;
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struct opp *opp;
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unsigned long freq, volt = 0, volt_old = 0, tol = 0;
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if (!freq_table) {
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dev_err(mpu_dev, "%s: cpu%d: no freq table!\n", __func__,
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policy->cpu);
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return -EINVAL;
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}
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ret = cpufreq_frequency_table_target(policy, freq_table, target_freq,
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relation, &i);
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if (ret) {
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dev_dbg(mpu_dev, "%s: cpu%d: no freq match for %d(ret=%d)\n",
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__func__, policy->cpu, target_freq, ret);
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return ret;
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}
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freqs.new = freq_table[i].frequency;
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if (!freqs.new) {
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dev_err(mpu_dev, "%s: cpu%d: no match for freq %d\n", __func__,
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policy->cpu, target_freq);
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return -EINVAL;
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}
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freqs.old = omap_getspeed(policy->cpu);
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if (freqs.old == freqs.new && policy->cur == freqs.new)
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return ret;
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freq = freqs.new * 1000;
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ret = clk_round_rate(mpu_clk, freq);
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if (IS_ERR_VALUE(ret)) {
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dev_warn(mpu_dev,
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"CPUfreq: Cannot find matching frequency for %lu\n",
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freq);
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return ret;
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}
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freq = ret;
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if (mpu_reg) {
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rcu_read_lock();
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opp = opp_find_freq_ceil(mpu_dev, &freq);
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if (IS_ERR(opp)) {
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rcu_read_unlock();
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dev_err(mpu_dev, "%s: unable to find MPU OPP for %d\n",
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__func__, freqs.new);
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return -EINVAL;
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}
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volt = opp_get_voltage(opp);
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rcu_read_unlock();
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tol = volt * OPP_TOLERANCE / 100;
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volt_old = regulator_get_voltage(mpu_reg);
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}
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dev_dbg(mpu_dev, "cpufreq-omap: %u MHz, %ld mV --> %u MHz, %ld mV\n",
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freqs.old / 1000, volt_old ? volt_old / 1000 : -1,
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freqs.new / 1000, volt ? volt / 1000 : -1);
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/* notifiers */
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cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
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/* scaling up? scale voltage before frequency */
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if (mpu_reg && (freqs.new > freqs.old)) {
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r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
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if (r < 0) {
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dev_warn(mpu_dev, "%s: unable to scale voltage up.\n",
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__func__);
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freqs.new = freqs.old;
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goto done;
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}
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}
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ret = clk_set_rate(mpu_clk, freqs.new * 1000);
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/* scaling down? scale voltage after frequency */
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if (mpu_reg && (freqs.new < freqs.old)) {
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r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
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if (r < 0) {
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dev_warn(mpu_dev, "%s: unable to scale voltage down.\n",
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__func__);
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ret = clk_set_rate(mpu_clk, freqs.old * 1000);
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freqs.new = freqs.old;
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goto done;
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}
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}
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freqs.new = omap_getspeed(policy->cpu);
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done:
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/* notifiers */
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cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
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return ret;
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}
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static inline void freq_table_free(void)
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{
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if (atomic_dec_and_test(&freq_table_users))
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opp_free_cpufreq_table(mpu_dev, &freq_table);
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}
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static int omap_cpu_init(struct cpufreq_policy *policy)
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{
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int result = 0;
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mpu_clk = clk_get(NULL, "cpufreq_ck");
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if (IS_ERR(mpu_clk))
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return PTR_ERR(mpu_clk);
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if (policy->cpu >= NR_CPUS) {
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result = -EINVAL;
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goto fail_ck;
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}
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policy->cur = omap_getspeed(policy->cpu);
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if (!freq_table)
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result = opp_init_cpufreq_table(mpu_dev, &freq_table);
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if (result) {
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dev_err(mpu_dev, "%s: cpu%d: failed creating freq table[%d]\n",
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__func__, policy->cpu, result);
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goto fail_ck;
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}
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atomic_inc_return(&freq_table_users);
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result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
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if (result)
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goto fail_table;
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cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
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policy->cur = omap_getspeed(policy->cpu);
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/*
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* On OMAP SMP configuartion, both processors share the voltage
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* and clock. So both CPUs needs to be scaled together and hence
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* needs software co-ordination. Use cpufreq affected_cpus
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* interface to handle this scenario. Additional is_smp() check
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* is to keep SMP_ON_UP build working.
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*/
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if (is_smp())
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cpumask_setall(policy->cpus);
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/* FIXME: what's the actual transition time? */
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policy->cpuinfo.transition_latency = 300 * 1000;
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return 0;
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fail_table:
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freq_table_free();
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fail_ck:
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clk_put(mpu_clk);
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return result;
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}
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static int omap_cpu_exit(struct cpufreq_policy *policy)
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{
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freq_table_free();
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clk_put(mpu_clk);
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return 0;
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}
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static struct freq_attr *omap_cpufreq_attr[] = {
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&cpufreq_freq_attr_scaling_available_freqs,
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NULL,
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};
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static struct cpufreq_driver omap_driver = {
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.flags = CPUFREQ_STICKY,
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.verify = omap_verify_speed,
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.target = omap_target,
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.get = omap_getspeed,
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.init = omap_cpu_init,
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.exit = omap_cpu_exit,
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.name = "omap",
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.attr = omap_cpufreq_attr,
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};
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static int omap_cpufreq_probe(struct platform_device *pdev)
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{
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mpu_dev = get_cpu_device(0);
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if (!mpu_dev) {
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pr_warning("%s: unable to get the mpu device\n", __func__);
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return -EINVAL;
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}
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mpu_reg = regulator_get(mpu_dev, "vcc");
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if (IS_ERR(mpu_reg)) {
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pr_warning("%s: unable to get MPU regulator\n", __func__);
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mpu_reg = NULL;
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} else {
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/*
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* Ensure physical regulator is present.
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* (e.g. could be dummy regulator.)
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*/
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if (regulator_get_voltage(mpu_reg) < 0) {
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pr_warn("%s: physical regulator not present for MPU\n",
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__func__);
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regulator_put(mpu_reg);
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mpu_reg = NULL;
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}
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}
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return cpufreq_register_driver(&omap_driver);
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}
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static int omap_cpufreq_remove(struct platform_device *pdev)
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{
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return cpufreq_unregister_driver(&omap_driver);
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}
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static struct platform_driver omap_cpufreq_platdrv = {
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.driver = {
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.name = "omap-cpufreq",
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.owner = THIS_MODULE,
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},
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.probe = omap_cpufreq_probe,
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.remove = omap_cpufreq_remove,
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};
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module_platform_driver(omap_cpufreq_platdrv);
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MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
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MODULE_LICENSE("GPL");
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