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Tony Lindgrenec6bced2005-07-10 19:58:20 +01001/*
Nishanth Menonffe4f0f2011-05-26 19:39:18 -07002 * CPU frequency scaling for OMAP using OPP information
Tony Lindgrenec6bced2005-07-10 19:58:20 +01003 *
4 * Copyright (C) 2005 Nokia Corporation
5 * Written by Tony Lindgren <tony@atomide.com>
6 *
7 * Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
8 *
Santosh Shilimkar731e0cc2010-08-11 17:02:43 -07009 * Copyright (C) 2007-2011 Texas Instruments, Inc.
10 * - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar
11 *
Tony Lindgrenec6bced2005-07-10 19:58:20 +010012 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2 as
14 * published by the Free Software Foundation.
15 */
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>
Russell Kingf8ce2542006-01-07 16:15:52 +000023#include <linux/clk.h>
Russell Kingfced80c2008-09-06 12:10:45 +010024#include <linux/io.h>
Nishanth Menone4db1c72013-09-19 16:03:52 -050025#include <linux/pm_opp.h>
Russell King46c12212011-09-21 16:53:00 -070026#include <linux/cpu.h>
Kevin Hilmanc1b547b2011-09-30 10:41:26 -070027#include <linux/module.h>
Nishanth Menon49ded522013-04-09 23:22:01 +000028#include <linux/platform_device.h>
Kevin Hilman53dfe8a2011-07-15 15:05:04 -070029#include <linux/regulator/consumer.h>
Santosh Shilimkar731e0cc2010-08-11 17:02:43 -070030
Santosh Shilimkar731e0cc2010-08-11 17:02:43 -070031#include <asm/smp_plat.h>
Russell King46c12212011-09-21 16:53:00 -070032#include <asm/cpu.h>
Santosh Shilimkar731e0cc2010-08-11 17:02:43 -070033
Afzal Mohammed42daffd2012-02-23 19:19:24 +053034/* OPP tolerance in percentage */
35#define OPP_TOLERANCE 4
36
Kevin Hilmanaeec2992009-01-27 19:13:38 -070037static struct cpufreq_frequency_table *freq_table;
Nishanth Menon1c782172011-05-26 19:39:20 -070038static atomic_t freq_table_users = ATOMIC_INIT(0);
Nishanth Menona820ffa2011-05-25 16:38:47 -070039static struct device *mpu_dev;
Kevin Hilman53dfe8a2011-07-15 15:05:04 -070040static struct regulator *mpu_reg;
Hiroshi DOYUb8488fb2007-08-30 12:46:39 +030041
Viresh Kumar9c0ebcf2013-10-25 19:45:48 +053042static int omap_target(struct cpufreq_policy *policy, unsigned int index)
Tony Lindgrenec6bced2005-07-10 19:58:20 +010043{
viresh kumar696d0b22013-11-13 15:39:23 +053044 int r, ret;
Nishanth Menon47d43ba2013-09-19 16:03:51 -050045 struct dev_pm_opp *opp;
Afzal Mohammed42daffd2012-02-23 19:19:24 +053046 unsigned long freq, volt = 0, volt_old = 0, tol = 0;
Viresh Kumard4019f02013-08-14 19:38:24 +053047 unsigned int old_freq, new_freq;
Tony Lindgrenec6bced2005-07-10 19:58:20 +010048
Viresh Kumar652ed952014-01-09 20:38:43 +053049 old_freq = policy->cur;
Viresh Kumard4019f02013-08-14 19:38:24 +053050 new_freq = freq_table[index].frequency;
Kevin Hilmanaeec2992009-01-27 19:13:38 -070051
Viresh Kumard4019f02013-08-14 19:38:24 +053052 freq = new_freq * 1000;
Viresh Kumar652ed952014-01-09 20:38:43 +053053 ret = clk_round_rate(policy->clk, freq);
Kevin Hilman8df0a662012-10-02 15:39:03 -070054 if (IS_ERR_VALUE(ret)) {
55 dev_warn(mpu_dev,
56 "CPUfreq: Cannot find matching frequency for %lu\n",
57 freq);
58 return ret;
59 }
60 freq = ret;
Kevin Hilman53dfe8a2011-07-15 15:05:04 -070061
62 if (mpu_reg) {
Nishanth Menonf44d1882013-01-18 19:52:32 +000063 rcu_read_lock();
Nishanth Menon5d4879c2013-09-19 16:03:50 -050064 opp = dev_pm_opp_find_freq_ceil(mpu_dev, &freq);
Kevin Hilman53dfe8a2011-07-15 15:05:04 -070065 if (IS_ERR(opp)) {
Nishanth Menonf44d1882013-01-18 19:52:32 +000066 rcu_read_unlock();
Kevin Hilman53dfe8a2011-07-15 15:05:04 -070067 dev_err(mpu_dev, "%s: unable to find MPU OPP for %d\n",
Viresh Kumard4019f02013-08-14 19:38:24 +053068 __func__, new_freq);
Kevin Hilman53dfe8a2011-07-15 15:05:04 -070069 return -EINVAL;
70 }
Nishanth Menon5d4879c2013-09-19 16:03:50 -050071 volt = dev_pm_opp_get_voltage(opp);
Nishanth Menonf44d1882013-01-18 19:52:32 +000072 rcu_read_unlock();
Afzal Mohammed42daffd2012-02-23 19:19:24 +053073 tol = volt * OPP_TOLERANCE / 100;
Kevin Hilman53dfe8a2011-07-15 15:05:04 -070074 volt_old = regulator_get_voltage(mpu_reg);
75 }
76
77 dev_dbg(mpu_dev, "cpufreq-omap: %u MHz, %ld mV --> %u MHz, %ld mV\n",
Viresh Kumard4019f02013-08-14 19:38:24 +053078 old_freq / 1000, volt_old ? volt_old / 1000 : -1,
79 new_freq / 1000, volt ? volt / 1000 : -1);
Viresh Kumar44a49a22013-06-19 11:18:20 +053080
Kevin Hilman53dfe8a2011-07-15 15:05:04 -070081 /* scaling up? scale voltage before frequency */
Viresh Kumard4019f02013-08-14 19:38:24 +053082 if (mpu_reg && (new_freq > old_freq)) {
Afzal Mohammed42daffd2012-02-23 19:19:24 +053083 r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
Kevin Hilman53dfe8a2011-07-15 15:05:04 -070084 if (r < 0) {
85 dev_warn(mpu_dev, "%s: unable to scale voltage up.\n",
86 __func__);
Viresh Kumard4019f02013-08-14 19:38:24 +053087 return r;
Kevin Hilman53dfe8a2011-07-15 15:05:04 -070088 }
89 }
Santosh Shilimkar731e0cc2010-08-11 17:02:43 -070090
Viresh Kumar652ed952014-01-09 20:38:43 +053091 ret = clk_set_rate(policy->clk, new_freq * 1000);
Santosh Shilimkar731e0cc2010-08-11 17:02:43 -070092
Kevin Hilman53dfe8a2011-07-15 15:05:04 -070093 /* scaling down? scale voltage after frequency */
Viresh Kumard4019f02013-08-14 19:38:24 +053094 if (mpu_reg && (new_freq < old_freq)) {
Afzal Mohammed42daffd2012-02-23 19:19:24 +053095 r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
Kevin Hilman53dfe8a2011-07-15 15:05:04 -070096 if (r < 0) {
97 dev_warn(mpu_dev, "%s: unable to scale voltage down.\n",
98 __func__);
Viresh Kumar652ed952014-01-09 20:38:43 +053099 clk_set_rate(policy->clk, old_freq * 1000);
Viresh Kumard4019f02013-08-14 19:38:24 +0530100 return r;
Kevin Hilman53dfe8a2011-07-15 15:05:04 -0700101 }
102 }
103
Tony Lindgrenec6bced2005-07-10 19:58:20 +0100104 return ret;
105}
106
Nishanth Menon1c782172011-05-26 19:39:20 -0700107static inline void freq_table_free(void)
108{
109 if (atomic_dec_and_test(&freq_table_users))
Nishanth Menon5d4879c2013-09-19 16:03:50 -0500110 dev_pm_opp_free_cpufreq_table(mpu_dev, &freq_table);
Nishanth Menon1c782172011-05-26 19:39:20 -0700111}
112
Paul Gortmaker27609842013-06-19 13:54:04 -0400113static int omap_cpu_init(struct cpufreq_policy *policy)
Tony Lindgrenec6bced2005-07-10 19:58:20 +0100114{
Viresh Kumar982bce12013-10-03 20:29:18 +0530115 int result;
Kevin Hilmanaeec2992009-01-27 19:13:38 -0700116
Viresh Kumar652ed952014-01-09 20:38:43 +0530117 policy->clk = clk_get(NULL, "cpufreq_ck");
118 if (IS_ERR(policy->clk))
119 return PTR_ERR(policy->clk);
Tony Lindgrenec6bced2005-07-10 19:58:20 +0100120
Viresh Kumar982bce12013-10-03 20:29:18 +0530121 if (!freq_table) {
Nishanth Menon5d4879c2013-09-19 16:03:50 -0500122 result = dev_pm_opp_init_cpufreq_table(mpu_dev, &freq_table);
Viresh Kumar982bce12013-10-03 20:29:18 +0530123 if (result) {
124 dev_err(mpu_dev,
125 "%s: cpu%d: failed creating freq table[%d]\n",
Nishanth Menonbf2a3592011-05-26 19:39:17 -0700126 __func__, policy->cpu, result);
Viresh Kumar982bce12013-10-03 20:29:18 +0530127 goto fail;
128 }
Kevin Hilmanaeec2992009-01-27 19:13:38 -0700129 }
130
Rajendra Nayak1b865212012-08-09 12:38:21 +0530131 atomic_inc_return(&freq_table_users);
132
Kevin Hilmanaeec2992009-01-27 19:13:38 -0700133 /* FIXME: what's the actual transition time? */
Viresh Kumar982bce12013-10-03 20:29:18 +0530134 result = cpufreq_generic_init(policy, freq_table, 300 * 1000);
135 if (!result)
136 return 0;
Tony Lindgrenec6bced2005-07-10 19:58:20 +0100137
Nishanth Menon1c782172011-05-26 19:39:20 -0700138 freq_table_free();
Viresh Kumar982bce12013-10-03 20:29:18 +0530139fail:
Viresh Kumar652ed952014-01-09 20:38:43 +0530140 clk_put(policy->clk);
Nishanth Menon11e04fd2011-05-26 19:39:19 -0700141 return result;
Tony Lindgrenec6bced2005-07-10 19:58:20 +0100142}
143
Hiroshi DOYUb8488fb2007-08-30 12:46:39 +0300144static int omap_cpu_exit(struct cpufreq_policy *policy)
145{
Nishanth Menon1c782172011-05-26 19:39:20 -0700146 freq_table_free();
Viresh Kumar652ed952014-01-09 20:38:43 +0530147 clk_put(policy->clk);
Hiroshi DOYUb8488fb2007-08-30 12:46:39 +0300148 return 0;
149}
150
Tony Lindgrenec6bced2005-07-10 19:58:20 +0100151static struct cpufreq_driver omap_driver = {
Viresh Kumarae6b4272013-12-03 11:20:45 +0530152 .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
Viresh Kumard5ca1642013-10-03 20:28:13 +0530153 .verify = cpufreq_generic_frequency_table_verify,
Viresh Kumar9c0ebcf2013-10-25 19:45:48 +0530154 .target_index = omap_target,
Viresh Kumar652ed952014-01-09 20:38:43 +0530155 .get = cpufreq_generic_get,
Tony Lindgrenec6bced2005-07-10 19:58:20 +0100156 .init = omap_cpu_init,
Hiroshi DOYUb8488fb2007-08-30 12:46:39 +0300157 .exit = omap_cpu_exit,
Tony Lindgrenec6bced2005-07-10 19:58:20 +0100158 .name = "omap",
Viresh Kumard5ca1642013-10-03 20:28:13 +0530159 .attr = cpufreq_generic_attr,
Tony Lindgrenec6bced2005-07-10 19:58:20 +0100160};
161
Nishanth Menon49ded522013-04-09 23:22:01 +0000162static int omap_cpufreq_probe(struct platform_device *pdev)
Tony Lindgrenec6bced2005-07-10 19:58:20 +0100163{
Kevin Hilman747a7f62012-09-06 14:22:44 -0700164 mpu_dev = get_cpu_device(0);
165 if (!mpu_dev) {
Nishanth Menona820ffa2011-05-25 16:38:47 -0700166 pr_warning("%s: unable to get the mpu device\n", __func__);
Kevin Hilman747a7f62012-09-06 14:22:44 -0700167 return -EINVAL;
Nishanth Menona820ffa2011-05-25 16:38:47 -0700168 }
169
Kevin Hilman53dfe8a2011-07-15 15:05:04 -0700170 mpu_reg = regulator_get(mpu_dev, "vcc");
171 if (IS_ERR(mpu_reg)) {
172 pr_warning("%s: unable to get MPU regulator\n", __func__);
173 mpu_reg = NULL;
174 } else {
175 /*
176 * Ensure physical regulator is present.
177 * (e.g. could be dummy regulator.)
178 */
179 if (regulator_get_voltage(mpu_reg) < 0) {
180 pr_warn("%s: physical regulator not present for MPU\n",
181 __func__);
182 regulator_put(mpu_reg);
183 mpu_reg = NULL;
184 }
185 }
186
Tony Lindgrenec6bced2005-07-10 19:58:20 +0100187 return cpufreq_register_driver(&omap_driver);
188}
189
Nishanth Menon49ded522013-04-09 23:22:01 +0000190static int omap_cpufreq_remove(struct platform_device *pdev)
Santosh Shilimkar731e0cc2010-08-11 17:02:43 -0700191{
Nishanth Menon49ded522013-04-09 23:22:01 +0000192 return cpufreq_unregister_driver(&omap_driver);
Santosh Shilimkar731e0cc2010-08-11 17:02:43 -0700193}
Kevin Hilmanaeec2992009-01-27 19:13:38 -0700194
Nishanth Menon49ded522013-04-09 23:22:01 +0000195static struct platform_driver omap_cpufreq_platdrv = {
196 .driver = {
197 .name = "omap-cpufreq",
Nishanth Menon49ded522013-04-09 23:22:01 +0000198 },
199 .probe = omap_cpufreq_probe,
200 .remove = omap_cpufreq_remove,
201};
202module_platform_driver(omap_cpufreq_platdrv);
203
Santosh Shilimkar731e0cc2010-08-11 17:02:43 -0700204MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
205MODULE_LICENSE("GPL");