dt-bindings: can: flexcan: list supported processors
[linux-2.6-microblaze.git] / drivers / cpufreq / omap-cpufreq.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  CPU frequency scaling for OMAP using OPP information
4  *
5  *  Copyright (C) 2005 Nokia Corporation
6  *  Written by Tony Lindgren <tony@atomide.com>
7  *
8  *  Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
9  *
10  * Copyright (C) 2007-2011 Texas Instruments, Inc.
11  * - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar
12  */
13
14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
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 #include <asm/smp_plat.h>
32 #include <asm/cpu.h>
33
34 /* OPP tolerance in percentage */
35 #define OPP_TOLERANCE   4
36
37 static struct cpufreq_frequency_table *freq_table;
38 static atomic_t freq_table_users = ATOMIC_INIT(0);
39 static struct device *mpu_dev;
40 static struct regulator *mpu_reg;
41
42 static int omap_target(struct cpufreq_policy *policy, unsigned int index)
43 {
44         int r, ret;
45         struct dev_pm_opp *opp;
46         unsigned long freq, volt = 0, volt_old = 0, tol = 0;
47         unsigned int old_freq, new_freq;
48
49         old_freq = policy->cur;
50         new_freq = freq_table[index].frequency;
51
52         freq = new_freq * 1000;
53         ret = clk_round_rate(policy->clk, freq);
54         if (ret < 0) {
55                 dev_warn(mpu_dev,
56                          "CPUfreq: Cannot find matching frequency for %lu\n",
57                          freq);
58                 return ret;
59         }
60         freq = ret;
61
62         if (mpu_reg) {
63                 opp = dev_pm_opp_find_freq_ceil(mpu_dev, &freq);
64                 if (IS_ERR(opp)) {
65                         dev_err(mpu_dev, "%s: unable to find MPU OPP for %d\n",
66                                 __func__, new_freq);
67                         return -EINVAL;
68                 }
69                 volt = dev_pm_opp_get_voltage(opp);
70                 dev_pm_opp_put(opp);
71                 tol = volt * OPP_TOLERANCE / 100;
72                 volt_old = regulator_get_voltage(mpu_reg);
73         }
74
75         dev_dbg(mpu_dev, "cpufreq-omap: %u MHz, %ld mV --> %u MHz, %ld mV\n", 
76                 old_freq / 1000, volt_old ? volt_old / 1000 : -1,
77                 new_freq / 1000, volt ? volt / 1000 : -1);
78
79         /* scaling up?  scale voltage before frequency */
80         if (mpu_reg && (new_freq > old_freq)) {
81                 r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
82                 if (r < 0) {
83                         dev_warn(mpu_dev, "%s: unable to scale voltage up.\n",
84                                  __func__);
85                         return r;
86                 }
87         }
88
89         ret = clk_set_rate(policy->clk, new_freq * 1000);
90
91         /* scaling down?  scale voltage after frequency */
92         if (mpu_reg && (new_freq < old_freq)) {
93                 r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
94                 if (r < 0) {
95                         dev_warn(mpu_dev, "%s: unable to scale voltage down.\n",
96                                  __func__);
97                         clk_set_rate(policy->clk, old_freq * 1000);
98                         return r;
99                 }
100         }
101
102         return ret;
103 }
104
105 static inline void freq_table_free(void)
106 {
107         if (atomic_dec_and_test(&freq_table_users))
108                 dev_pm_opp_free_cpufreq_table(mpu_dev, &freq_table);
109 }
110
111 static int omap_cpu_init(struct cpufreq_policy *policy)
112 {
113         int result;
114
115         policy->clk = clk_get(NULL, "cpufreq_ck");
116         if (IS_ERR(policy->clk))
117                 return PTR_ERR(policy->clk);
118
119         if (!freq_table) {
120                 result = dev_pm_opp_init_cpufreq_table(mpu_dev, &freq_table);
121                 if (result) {
122                         dev_err(mpu_dev,
123                                 "%s: cpu%d: failed creating freq table[%d]\n",
124                                 __func__, policy->cpu, result);
125                         clk_put(policy->clk);
126                         return result;
127                 }
128         }
129
130         atomic_inc_return(&freq_table_users);
131
132         /* FIXME: what's the actual transition time? */
133         cpufreq_generic_init(policy, freq_table, 300 * 1000);
134         dev_pm_opp_of_register_em(mpu_dev, policy->cpus);
135
136         return 0;
137 }
138
139 static int omap_cpu_exit(struct cpufreq_policy *policy)
140 {
141         freq_table_free();
142         clk_put(policy->clk);
143         return 0;
144 }
145
146 static struct cpufreq_driver omap_driver = {
147         .flags          = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
148         .verify         = cpufreq_generic_frequency_table_verify,
149         .target_index   = omap_target,
150         .get            = cpufreq_generic_get,
151         .init           = omap_cpu_init,
152         .exit           = omap_cpu_exit,
153         .name           = "omap",
154         .attr           = cpufreq_generic_attr,
155 };
156
157 static int omap_cpufreq_probe(struct platform_device *pdev)
158 {
159         mpu_dev = get_cpu_device(0);
160         if (!mpu_dev) {
161                 pr_warn("%s: unable to get the MPU device\n", __func__);
162                 return -EINVAL;
163         }
164
165         mpu_reg = regulator_get(mpu_dev, "vcc");
166         if (IS_ERR(mpu_reg)) {
167                 pr_warn("%s: unable to get MPU regulator\n", __func__);
168                 mpu_reg = NULL;
169         } else {
170                 /* 
171                  * Ensure physical regulator is present.
172                  * (e.g. could be dummy regulator.)
173                  */
174                 if (regulator_get_voltage(mpu_reg) < 0) {
175                         pr_warn("%s: physical regulator not present for MPU\n",
176                                 __func__);
177                         regulator_put(mpu_reg);
178                         mpu_reg = NULL;
179                 }
180         }
181
182         return cpufreq_register_driver(&omap_driver);
183 }
184
185 static int omap_cpufreq_remove(struct platform_device *pdev)
186 {
187         return cpufreq_unregister_driver(&omap_driver);
188 }
189
190 static struct platform_driver omap_cpufreq_platdrv = {
191         .driver = {
192                 .name   = "omap-cpufreq",
193         },
194         .probe          = omap_cpufreq_probe,
195         .remove         = omap_cpufreq_remove,
196 };
197 module_platform_driver(omap_cpufreq_platdrv);
198
199 MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
200 MODULE_LICENSE("GPL");