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be2de99b | 1 | /* |
b3748ddd MB |
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 | #include <linux/kernel.h> | |
12 | #include <linux/types.h> | |
13 | #include <linux/init.h> | |
14 | #include <linux/cpufreq.h> | |
15 | #include <linux/clk.h> | |
16 | #include <linux/err.h> | |
17 | #include <linux/regulator/consumer.h> | |
a6ee8779 | 18 | #include <linux/module.h> |
b3748ddd MB |
19 | |
20 | static struct clk *armclk; | |
21 | static struct regulator *vddarm; | |
43f1069e | 22 | static unsigned long regulator_latency; |
b3748ddd MB |
23 | |
24 | #ifdef CONFIG_CPU_S3C6410 | |
25 | struct s3c64xx_dvfs { | |
26 | unsigned int vddarm_min; | |
27 | unsigned int vddarm_max; | |
28 | }; | |
29 | ||
30 | static struct s3c64xx_dvfs s3c64xx_dvfs_table[] = { | |
e9c08f0d MB |
31 | [0] = { 1000000, 1150000 }, |
32 | [1] = { 1050000, 1150000 }, | |
33 | [2] = { 1100000, 1150000 }, | |
34 | [3] = { 1200000, 1350000 }, | |
c6e2d685 | 35 | [4] = { 1300000, 1350000 }, |
b3748ddd MB |
36 | }; |
37 | ||
38 | static struct cpufreq_frequency_table s3c64xx_freq_table[] = { | |
39 | { 0, 66000 }, | |
ef993ef8 | 40 | { 0, 100000 }, |
b3748ddd | 41 | { 0, 133000 }, |
ef993ef8 | 42 | { 1, 200000 }, |
b3748ddd MB |
43 | { 1, 222000 }, |
44 | { 1, 266000 }, | |
45 | { 2, 333000 }, | |
46 | { 2, 400000 }, | |
e9c08f0d MB |
47 | { 2, 532000 }, |
48 | { 2, 533000 }, | |
49 | { 3, 667000 }, | |
c6e2d685 | 50 | { 4, 800000 }, |
b3748ddd MB |
51 | { 0, CPUFREQ_TABLE_END }, |
52 | }; | |
53 | #endif | |
54 | ||
55 | static int s3c64xx_cpufreq_verify_speed(struct cpufreq_policy *policy) | |
56 | { | |
57 | if (policy->cpu != 0) | |
58 | return -EINVAL; | |
59 | ||
60 | return cpufreq_frequency_table_verify(policy, s3c64xx_freq_table); | |
61 | } | |
62 | ||
63 | static unsigned int s3c64xx_cpufreq_get_speed(unsigned int cpu) | |
64 | { | |
65 | if (cpu != 0) | |
66 | return 0; | |
67 | ||
68 | return clk_get_rate(armclk) / 1000; | |
69 | } | |
70 | ||
71 | static int s3c64xx_cpufreq_set_target(struct cpufreq_policy *policy, | |
72 | unsigned int target_freq, | |
73 | unsigned int relation) | |
74 | { | |
75 | int ret; | |
76 | unsigned int i; | |
77 | struct cpufreq_freqs freqs; | |
78 | struct s3c64xx_dvfs *dvfs; | |
79 | ||
80 | ret = cpufreq_frequency_table_target(policy, s3c64xx_freq_table, | |
81 | target_freq, relation, &i); | |
82 | if (ret != 0) | |
83 | return ret; | |
84 | ||
85 | freqs.cpu = 0; | |
86 | freqs.old = clk_get_rate(armclk) / 1000; | |
87 | freqs.new = s3c64xx_freq_table[i].frequency; | |
88 | freqs.flags = 0; | |
89 | dvfs = &s3c64xx_dvfs_table[s3c64xx_freq_table[i].index]; | |
90 | ||
91 | if (freqs.old == freqs.new) | |
92 | return 0; | |
93 | ||
94 | pr_debug("cpufreq: Transition %d-%dkHz\n", freqs.old, freqs.new); | |
95 | ||
96 | cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); | |
97 | ||
98 | #ifdef CONFIG_REGULATOR | |
99 | if (vddarm && freqs.new > freqs.old) { | |
100 | ret = regulator_set_voltage(vddarm, | |
101 | dvfs->vddarm_min, | |
102 | dvfs->vddarm_max); | |
103 | if (ret != 0) { | |
104 | pr_err("cpufreq: Failed to set VDDARM for %dkHz: %d\n", | |
105 | freqs.new, ret); | |
106 | goto err; | |
107 | } | |
108 | } | |
109 | #endif | |
110 | ||
111 | ret = clk_set_rate(armclk, freqs.new * 1000); | |
112 | if (ret < 0) { | |
113 | pr_err("cpufreq: Failed to set rate %dkHz: %d\n", | |
114 | freqs.new, ret); | |
115 | goto err; | |
116 | } | |
117 | ||
fb3b1fef MB |
118 | cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); |
119 | ||
b3748ddd MB |
120 | #ifdef CONFIG_REGULATOR |
121 | if (vddarm && freqs.new < freqs.old) { | |
122 | ret = regulator_set_voltage(vddarm, | |
123 | dvfs->vddarm_min, | |
124 | dvfs->vddarm_max); | |
125 | if (ret != 0) { | |
126 | pr_err("cpufreq: Failed to set VDDARM for %dkHz: %d\n", | |
127 | freqs.new, ret); | |
128 | goto err_clk; | |
129 | } | |
130 | } | |
131 | #endif | |
132 | ||
b3748ddd MB |
133 | pr_debug("cpufreq: Set actual frequency %lukHz\n", |
134 | clk_get_rate(armclk) / 1000); | |
135 | ||
136 | return 0; | |
137 | ||
138 | err_clk: | |
139 | if (clk_set_rate(armclk, freqs.old * 1000) < 0) | |
140 | pr_err("Failed to restore original clock rate\n"); | |
141 | err: | |
142 | cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); | |
143 | ||
144 | return ret; | |
145 | } | |
146 | ||
147 | #ifdef CONFIG_REGULATOR | |
43f1069e | 148 | static void __init s3c64xx_cpufreq_config_regulator(void) |
b3748ddd MB |
149 | { |
150 | int count, v, i, found; | |
151 | struct cpufreq_frequency_table *freq; | |
152 | struct s3c64xx_dvfs *dvfs; | |
153 | ||
154 | count = regulator_count_voltages(vddarm); | |
155 | if (count < 0) { | |
156 | pr_err("cpufreq: Unable to check supported voltages\n"); | |
b3748ddd MB |
157 | } |
158 | ||
159 | freq = s3c64xx_freq_table; | |
43f1069e | 160 | while (count > 0 && freq->frequency != CPUFREQ_TABLE_END) { |
b3748ddd MB |
161 | if (freq->frequency == CPUFREQ_ENTRY_INVALID) |
162 | continue; | |
163 | ||
164 | dvfs = &s3c64xx_dvfs_table[freq->index]; | |
165 | found = 0; | |
166 | ||
167 | for (i = 0; i < count; i++) { | |
168 | v = regulator_list_voltage(vddarm, i); | |
169 | if (v >= dvfs->vddarm_min && v <= dvfs->vddarm_max) | |
170 | found = 1; | |
171 | } | |
172 | ||
173 | if (!found) { | |
174 | pr_debug("cpufreq: %dkHz unsupported by regulator\n", | |
175 | freq->frequency); | |
176 | freq->frequency = CPUFREQ_ENTRY_INVALID; | |
177 | } | |
178 | ||
179 | freq++; | |
180 | } | |
43f1069e MB |
181 | |
182 | /* Guess based on having to do an I2C/SPI write; in future we | |
183 | * will be able to query the regulator performance here. */ | |
184 | regulator_latency = 1 * 1000 * 1000; | |
b3748ddd MB |
185 | } |
186 | #endif | |
187 | ||
6d0de157 | 188 | static int s3c64xx_cpufreq_driver_init(struct cpufreq_policy *policy) |
b3748ddd MB |
189 | { |
190 | int ret; | |
191 | struct cpufreq_frequency_table *freq; | |
192 | ||
193 | if (policy->cpu != 0) | |
194 | return -EINVAL; | |
195 | ||
196 | if (s3c64xx_freq_table == NULL) { | |
197 | pr_err("cpufreq: No frequency information for this CPU\n"); | |
198 | return -ENODEV; | |
199 | } | |
200 | ||
201 | armclk = clk_get(NULL, "armclk"); | |
202 | if (IS_ERR(armclk)) { | |
203 | pr_err("cpufreq: Unable to obtain ARMCLK: %ld\n", | |
204 | PTR_ERR(armclk)); | |
205 | return PTR_ERR(armclk); | |
206 | } | |
207 | ||
208 | #ifdef CONFIG_REGULATOR | |
209 | vddarm = regulator_get(NULL, "vddarm"); | |
210 | if (IS_ERR(vddarm)) { | |
211 | ret = PTR_ERR(vddarm); | |
212 | pr_err("cpufreq: Failed to obtain VDDARM: %d\n", ret); | |
213 | pr_err("cpufreq: Only frequency scaling available\n"); | |
214 | vddarm = NULL; | |
215 | } else { | |
43f1069e | 216 | s3c64xx_cpufreq_config_regulator(); |
b3748ddd MB |
217 | } |
218 | #endif | |
219 | ||
220 | freq = s3c64xx_freq_table; | |
221 | while (freq->frequency != CPUFREQ_TABLE_END) { | |
222 | unsigned long r; | |
223 | ||
224 | /* Check for frequencies we can generate */ | |
225 | r = clk_round_rate(armclk, freq->frequency * 1000); | |
226 | r /= 1000; | |
383af9c2 MB |
227 | if (r != freq->frequency) { |
228 | pr_debug("cpufreq: %dkHz unsupported by clock\n", | |
229 | freq->frequency); | |
b3748ddd | 230 | freq->frequency = CPUFREQ_ENTRY_INVALID; |
383af9c2 | 231 | } |
b3748ddd MB |
232 | |
233 | /* If we have no regulator then assume startup | |
234 | * frequency is the maximum we can support. */ | |
235 | if (!vddarm && freq->frequency > s3c64xx_cpufreq_get_speed(0)) | |
236 | freq->frequency = CPUFREQ_ENTRY_INVALID; | |
237 | ||
238 | freq++; | |
239 | } | |
240 | ||
241 | policy->cur = clk_get_rate(armclk) / 1000; | |
242 | ||
43f1069e MB |
243 | /* Datasheet says PLL stabalisation time (if we were to use |
244 | * the PLLs, which we don't currently) is ~300us worst case, | |
245 | * but add some fudge. | |
246 | */ | |
247 | policy->cpuinfo.transition_latency = (500 * 1000) + regulator_latency; | |
b3748ddd MB |
248 | |
249 | ret = cpufreq_frequency_table_cpuinfo(policy, s3c64xx_freq_table); | |
250 | if (ret != 0) { | |
251 | pr_err("cpufreq: Failed to configure frequency table: %d\n", | |
252 | ret); | |
253 | regulator_put(vddarm); | |
254 | clk_put(armclk); | |
255 | } | |
256 | ||
257 | return ret; | |
258 | } | |
259 | ||
260 | static struct cpufreq_driver s3c64xx_cpufreq_driver = { | |
261 | .owner = THIS_MODULE, | |
262 | .flags = 0, | |
263 | .verify = s3c64xx_cpufreq_verify_speed, | |
264 | .target = s3c64xx_cpufreq_set_target, | |
265 | .get = s3c64xx_cpufreq_get_speed, | |
266 | .init = s3c64xx_cpufreq_driver_init, | |
267 | .name = "s3c", | |
268 | }; | |
269 | ||
270 | static int __init s3c64xx_cpufreq_init(void) | |
271 | { | |
272 | return cpufreq_register_driver(&s3c64xx_cpufreq_driver); | |
273 | } | |
274 | module_init(s3c64xx_cpufreq_init); |