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17#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18
19#include <linux/types.h>
20#include <linux/kernel.h>
21#include <linux/sched.h>
22#include <linux/cpufreq.h>
23#include <linux/delay.h>
24#include <linux/init.h>
25#include <linux/err.h>
26#include <linux/clk.h>
27#include <linux/io.h>
28#include <linux/pm_opp.h>
29#include <linux/cpu.h>
30#include <linux/module.h>
31#include <linux/platform_device.h>
32#include <linux/regulator/consumer.h>
33
34#include <asm/smp_plat.h>
35#include <asm/cpu.h>
36
37
38#define OPP_TOLERANCE 4
39
40static struct cpufreq_frequency_table *freq_table;
41static atomic_t freq_table_users = ATOMIC_INIT(0);
42static struct device *mpu_dev;
43static struct regulator *mpu_reg;
44
45static int omap_target(struct cpufreq_policy *policy, unsigned int index)
46{
47 int r, ret;
48 struct dev_pm_opp *opp;
49 unsigned long freq, volt = 0, volt_old = 0, tol = 0;
50 unsigned int old_freq, new_freq;
51
52 old_freq = policy->cur;
53 new_freq = freq_table[index].frequency;
54
55 freq = new_freq * 1000;
56 ret = clk_round_rate(policy->clk, freq);
57 if (ret < 0) {
58 dev_warn(mpu_dev,
59 "CPUfreq: Cannot find matching frequency for %lu\n",
60 freq);
61 return ret;
62 }
63 freq = ret;
64
65 if (mpu_reg) {
66 rcu_read_lock();
67 opp = dev_pm_opp_find_freq_ceil(mpu_dev, &freq);
68 if (IS_ERR(opp)) {
69 rcu_read_unlock();
70 dev_err(mpu_dev, "%s: unable to find MPU OPP for %d\n",
71 __func__, new_freq);
72 return -EINVAL;
73 }
74 volt = dev_pm_opp_get_voltage(opp);
75 rcu_read_unlock();
76 tol = volt * OPP_TOLERANCE / 100;
77 volt_old = regulator_get_voltage(mpu_reg);
78 }
79
80 dev_dbg(mpu_dev, "cpufreq-omap: %u MHz, %ld mV --> %u MHz, %ld mV\n",
81 old_freq / 1000, volt_old ? volt_old / 1000 : -1,
82 new_freq / 1000, volt ? volt / 1000 : -1);
83
84
85 if (mpu_reg && (new_freq > old_freq)) {
86 r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
87 if (r < 0) {
88 dev_warn(mpu_dev, "%s: unable to scale voltage up.\n",
89 __func__);
90 return r;
91 }
92 }
93
94 ret = clk_set_rate(policy->clk, new_freq * 1000);
95
96
97 if (mpu_reg && (new_freq < old_freq)) {
98 r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
99 if (r < 0) {
100 dev_warn(mpu_dev, "%s: unable to scale voltage down.\n",
101 __func__);
102 clk_set_rate(policy->clk, old_freq * 1000);
103 return r;
104 }
105 }
106
107 return ret;
108}
109
110static inline void freq_table_free(void)
111{
112 if (atomic_dec_and_test(&freq_table_users))
113 dev_pm_opp_free_cpufreq_table(mpu_dev, &freq_table);
114}
115
116static int omap_cpu_init(struct cpufreq_policy *policy)
117{
118 int result;
119
120 policy->clk = clk_get(NULL, "cpufreq_ck");
121 if (IS_ERR(policy->clk))
122 return PTR_ERR(policy->clk);
123
124 if (!freq_table) {
125 result = dev_pm_opp_init_cpufreq_table(mpu_dev, &freq_table);
126 if (result) {
127 dev_err(mpu_dev,
128 "%s: cpu%d: failed creating freq table[%d]\n",
129 __func__, policy->cpu, result);
130 goto fail;
131 }
132 }
133
134 atomic_inc_return(&freq_table_users);
135
136
137 result = cpufreq_generic_init(policy, freq_table, 300 * 1000);
138 if (!result)
139 return 0;
140
141 freq_table_free();
142fail:
143 clk_put(policy->clk);
144 return result;
145}
146
147static int omap_cpu_exit(struct cpufreq_policy *policy)
148{
149 freq_table_free();
150 clk_put(policy->clk);
151 return 0;
152}
153
154static struct cpufreq_driver omap_driver = {
155 .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
156 .verify = cpufreq_generic_frequency_table_verify,
157 .target_index = omap_target,
158 .get = cpufreq_generic_get,
159 .init = omap_cpu_init,
160 .exit = omap_cpu_exit,
161 .name = "omap",
162 .attr = cpufreq_generic_attr,
163};
164
165static int omap_cpufreq_probe(struct platform_device *pdev)
166{
167 mpu_dev = get_cpu_device(0);
168 if (!mpu_dev) {
169 pr_warn("%s: unable to get the MPU device\n", __func__);
170 return -EINVAL;
171 }
172
173 mpu_reg = regulator_get(mpu_dev, "vcc");
174 if (IS_ERR(mpu_reg)) {
175 pr_warn("%s: unable to get MPU regulator\n", __func__);
176 mpu_reg = NULL;
177 } else {
178
179
180
181
182 if (regulator_get_voltage(mpu_reg) < 0) {
183 pr_warn("%s: physical regulator not present for MPU\n",
184 __func__);
185 regulator_put(mpu_reg);
186 mpu_reg = NULL;
187 }
188 }
189
190 return cpufreq_register_driver(&omap_driver);
191}
192
193static int omap_cpufreq_remove(struct platform_device *pdev)
194{
195 return cpufreq_unregister_driver(&omap_driver);
196}
197
198static struct platform_driver omap_cpufreq_platdrv = {
199 .driver = {
200 .name = "omap-cpufreq",
201 },
202 .probe = omap_cpufreq_probe,
203 .remove = omap_cpufreq_remove,
204};
205module_platform_driver(omap_cpufreq_platdrv);
206
207MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
208MODULE_LICENSE("GPL");
209
