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1 | /* | |
2 | * Copyright 2009 Wolfson Microelectronics plc | |
3 | * | |
4 | * S3C64xx CPUfreq Support | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | */ | |
10 | ||
11 | #define pr_fmt(fmt) "cpufreq: " fmt | |
12 | ||
13 | #include <linux/kernel.h> | |
14 | #include <linux/types.h> | |
15 | #include <linux/init.h> | |
16 | #include <linux/cpufreq.h> | |
17 | #include <linux/clk.h> | |
18 | #include <linux/err.h> | |
19 | #include <linux/regulator/consumer.h> | |
20 | #include <linux/module.h> | |
21 | ||
22 | static struct clk *armclk; | |
23 | static struct regulator *vddarm; | |
24 | static unsigned long regulator_latency; | |
25 | ||
26 | #ifdef CONFIG_CPU_S3C6410 | |
27 | struct s3c64xx_dvfs { | |
28 | unsigned int vddarm_min; | |
29 | unsigned int vddarm_max; | |
30 | }; | |
31 | ||
32 | static struct s3c64xx_dvfs s3c64xx_dvfs_table[] = { | |
33 | [0] = { 1000000, 1150000 }, | |
34 | [1] = { 1050000, 1150000 }, | |
35 | [2] = { 1100000, 1150000 }, | |
36 | [3] = { 1200000, 1350000 }, | |
37 | [4] = { 1300000, 1350000 }, | |
38 | }; | |
39 | ||
40 | static struct cpufreq_frequency_table s3c64xx_freq_table[] = { | |
41 | { 0, 66000 }, | |
42 | { 0, 100000 }, | |
43 | { 0, 133000 }, | |
44 | { 1, 200000 }, | |
45 | { 1, 222000 }, | |
46 | { 1, 266000 }, | |
47 | { 2, 333000 }, | |
48 | { 2, 400000 }, | |
49 | { 2, 532000 }, | |
50 | { 2, 533000 }, | |
51 | { 3, 667000 }, | |
52 | { 4, 800000 }, | |
53 | { 0, CPUFREQ_TABLE_END }, | |
54 | }; | |
55 | #endif | |
56 | ||
57 | static unsigned int s3c64xx_cpufreq_get_speed(unsigned int cpu) | |
58 | { | |
59 | if (cpu != 0) | |
60 | return 0; | |
61 | ||
62 | return clk_get_rate(armclk) / 1000; | |
63 | } | |
64 | ||
65 | static int s3c64xx_cpufreq_set_target(struct cpufreq_policy *policy, | |
66 | unsigned int index) | |
67 | { | |
68 | struct s3c64xx_dvfs *dvfs; | |
69 | unsigned int old_freq, new_freq; | |
70 | int ret; | |
71 | ||
72 | old_freq = clk_get_rate(armclk) / 1000; | |
73 | new_freq = s3c64xx_freq_table[index].frequency; | |
74 | dvfs = &s3c64xx_dvfs_table[s3c64xx_freq_table[index].driver_data]; | |
75 | ||
76 | #ifdef CONFIG_REGULATOR | |
77 | if (vddarm && new_freq > old_freq) { | |
78 | ret = regulator_set_voltage(vddarm, | |
79 | dvfs->vddarm_min, | |
80 | dvfs->vddarm_max); | |
81 | if (ret != 0) { | |
82 | pr_err("Failed to set VDDARM for %dkHz: %d\n", | |
83 | new_freq, ret); | |
84 | return ret; | |
85 | } | |
86 | } | |
87 | #endif | |
88 | ||
89 | ret = clk_set_rate(armclk, new_freq * 1000); | |
90 | if (ret < 0) { | |
91 | pr_err("Failed to set rate %dkHz: %d\n", | |
92 | new_freq, ret); | |
93 | return ret; | |
94 | } | |
95 | ||
96 | #ifdef CONFIG_REGULATOR | |
97 | if (vddarm && new_freq < old_freq) { | |
98 | ret = regulator_set_voltage(vddarm, | |
99 | dvfs->vddarm_min, | |
100 | dvfs->vddarm_max); | |
101 | if (ret != 0) { | |
102 | pr_err("Failed to set VDDARM for %dkHz: %d\n", | |
103 | new_freq, ret); | |
104 | if (clk_set_rate(armclk, old_freq * 1000) < 0) | |
105 | pr_err("Failed to restore original clock rate\n"); | |
106 | ||
107 | return ret; | |
108 | } | |
109 | } | |
110 | #endif | |
111 | ||
112 | pr_debug("Set actual frequency %lukHz\n", | |
113 | clk_get_rate(armclk) / 1000); | |
114 | ||
115 | return 0; | |
116 | } | |
117 | ||
118 | #ifdef CONFIG_REGULATOR | |
119 | static void __init s3c64xx_cpufreq_config_regulator(void) | |
120 | { | |
121 | int count, v, i, found; | |
122 | struct cpufreq_frequency_table *freq; | |
123 | struct s3c64xx_dvfs *dvfs; | |
124 | ||
125 | count = regulator_count_voltages(vddarm); | |
126 | if (count < 0) { | |
127 | pr_err("Unable to check supported voltages\n"); | |
128 | } | |
129 | ||
130 | freq = s3c64xx_freq_table; | |
131 | while (count > 0 && freq->frequency != CPUFREQ_TABLE_END) { | |
132 | if (freq->frequency == CPUFREQ_ENTRY_INVALID) | |
133 | continue; | |
134 | ||
135 | dvfs = &s3c64xx_dvfs_table[freq->driver_data]; | |
136 | found = 0; | |
137 | ||
138 | for (i = 0; i < count; i++) { | |
139 | v = regulator_list_voltage(vddarm, i); | |
140 | if (v >= dvfs->vddarm_min && v <= dvfs->vddarm_max) | |
141 | found = 1; | |
142 | } | |
143 | ||
144 | if (!found) { | |
145 | pr_debug("%dkHz unsupported by regulator\n", | |
146 | freq->frequency); | |
147 | freq->frequency = CPUFREQ_ENTRY_INVALID; | |
148 | } | |
149 | ||
150 | freq++; | |
151 | } | |
152 | ||
153 | /* Guess based on having to do an I2C/SPI write; in future we | |
154 | * will be able to query the regulator performance here. */ | |
155 | regulator_latency = 1 * 1000 * 1000; | |
156 | } | |
157 | #endif | |
158 | ||
159 | static int s3c64xx_cpufreq_driver_init(struct cpufreq_policy *policy) | |
160 | { | |
161 | int ret; | |
162 | struct cpufreq_frequency_table *freq; | |
163 | ||
164 | if (policy->cpu != 0) | |
165 | return -EINVAL; | |
166 | ||
167 | if (s3c64xx_freq_table == NULL) { | |
168 | pr_err("No frequency information for this CPU\n"); | |
169 | return -ENODEV; | |
170 | } | |
171 | ||
172 | armclk = clk_get(NULL, "armclk"); | |
173 | if (IS_ERR(armclk)) { | |
174 | pr_err("Unable to obtain ARMCLK: %ld\n", | |
175 | PTR_ERR(armclk)); | |
176 | return PTR_ERR(armclk); | |
177 | } | |
178 | ||
179 | #ifdef CONFIG_REGULATOR | |
180 | vddarm = regulator_get(NULL, "vddarm"); | |
181 | if (IS_ERR(vddarm)) { | |
182 | ret = PTR_ERR(vddarm); | |
183 | pr_err("Failed to obtain VDDARM: %d\n", ret); | |
184 | pr_err("Only frequency scaling available\n"); | |
185 | vddarm = NULL; | |
186 | } else { | |
187 | s3c64xx_cpufreq_config_regulator(); | |
188 | } | |
189 | #endif | |
190 | ||
191 | freq = s3c64xx_freq_table; | |
192 | while (freq->frequency != CPUFREQ_TABLE_END) { | |
193 | unsigned long r; | |
194 | ||
195 | /* Check for frequencies we can generate */ | |
196 | r = clk_round_rate(armclk, freq->frequency * 1000); | |
197 | r /= 1000; | |
198 | if (r != freq->frequency) { | |
199 | pr_debug("%dkHz unsupported by clock\n", | |
200 | freq->frequency); | |
201 | freq->frequency = CPUFREQ_ENTRY_INVALID; | |
202 | } | |
203 | ||
204 | /* If we have no regulator then assume startup | |
205 | * frequency is the maximum we can support. */ | |
206 | if (!vddarm && freq->frequency > s3c64xx_cpufreq_get_speed(0)) | |
207 | freq->frequency = CPUFREQ_ENTRY_INVALID; | |
208 | ||
209 | freq++; | |
210 | } | |
211 | ||
212 | /* Datasheet says PLL stabalisation time (if we were to use | |
213 | * the PLLs, which we don't currently) is ~300us worst case, | |
214 | * but add some fudge. | |
215 | */ | |
216 | ret = cpufreq_generic_init(policy, s3c64xx_freq_table, | |
217 | (500 * 1000) + regulator_latency); | |
218 | if (ret != 0) { | |
219 | pr_err("Failed to configure frequency table: %d\n", | |
220 | ret); | |
221 | regulator_put(vddarm); | |
222 | clk_put(armclk); | |
223 | } | |
224 | ||
225 | return ret; | |
226 | } | |
227 | ||
228 | static struct cpufreq_driver s3c64xx_cpufreq_driver = { | |
229 | .flags = 0, | |
230 | .verify = cpufreq_generic_frequency_table_verify, | |
231 | .target_index = s3c64xx_cpufreq_set_target, | |
232 | .get = s3c64xx_cpufreq_get_speed, | |
233 | .init = s3c64xx_cpufreq_driver_init, | |
234 | .name = "s3c", | |
235 | }; | |
236 | ||
237 | static int __init s3c64xx_cpufreq_init(void) | |
238 | { | |
239 | return cpufreq_register_driver(&s3c64xx_cpufreq_driver); | |
240 | } | |
241 | module_init(s3c64xx_cpufreq_init); |