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95ceafd4 SG |
1 | /* |
2 | * Copyright (C) 2012 Freescale Semiconductor, Inc. | |
3 | * | |
4 | * The OPP code in function cpu0_set_target() is reused from | |
5 | * drivers/cpufreq/omap-cpufreq.c | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | */ | |
11 | ||
12 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
13 | ||
14 | #include <linux/clk.h> | |
e1825b25 | 15 | #include <linux/cpu.h> |
95ceafd4 SG |
16 | #include <linux/cpufreq.h> |
17 | #include <linux/err.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/of.h> | |
e4db1c74 | 20 | #include <linux/pm_opp.h> |
5553f9e2 | 21 | #include <linux/platform_device.h> |
95ceafd4 SG |
22 | #include <linux/regulator/consumer.h> |
23 | #include <linux/slab.h> | |
24 | ||
25 | static unsigned int transition_latency; | |
26 | static unsigned int voltage_tolerance; /* in percentage */ | |
27 | ||
28 | static struct device *cpu_dev; | |
29 | static struct clk *cpu_clk; | |
30 | static struct regulator *cpu_reg; | |
31 | static struct cpufreq_frequency_table *freq_table; | |
32 | ||
95ceafd4 SG |
33 | static unsigned int cpu0_get_speed(unsigned int cpu) |
34 | { | |
35 | return clk_get_rate(cpu_clk) / 1000; | |
36 | } | |
37 | ||
9c0ebcf7 | 38 | static int cpu0_set_target(struct cpufreq_policy *policy, unsigned int index) |
95ceafd4 | 39 | { |
47d43ba7 | 40 | struct dev_pm_opp *opp; |
5df60559 | 41 | unsigned long volt = 0, volt_old = 0, tol = 0; |
d4019f0a | 42 | unsigned int old_freq, new_freq; |
0ca68436 | 43 | long freq_Hz, freq_exact; |
95ceafd4 SG |
44 | int ret; |
45 | ||
95ceafd4 SG |
46 | freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000); |
47 | if (freq_Hz < 0) | |
48 | freq_Hz = freq_table[index].frequency * 1000; | |
95ceafd4 | 49 | |
d4019f0a VK |
50 | freq_exact = freq_Hz; |
51 | new_freq = freq_Hz / 1000; | |
52 | old_freq = clk_get_rate(cpu_clk) / 1000; | |
95ceafd4 | 53 | |
4a511de9 | 54 | if (!IS_ERR(cpu_reg)) { |
78e8eb8f | 55 | rcu_read_lock(); |
5d4879cd | 56 | opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_Hz); |
95ceafd4 | 57 | if (IS_ERR(opp)) { |
78e8eb8f | 58 | rcu_read_unlock(); |
95ceafd4 | 59 | pr_err("failed to find OPP for %ld\n", freq_Hz); |
d4019f0a | 60 | return PTR_ERR(opp); |
95ceafd4 | 61 | } |
5d4879cd | 62 | volt = dev_pm_opp_get_voltage(opp); |
78e8eb8f | 63 | rcu_read_unlock(); |
95ceafd4 SG |
64 | tol = volt * voltage_tolerance / 100; |
65 | volt_old = regulator_get_voltage(cpu_reg); | |
66 | } | |
67 | ||
68 | pr_debug("%u MHz, %ld mV --> %u MHz, %ld mV\n", | |
d4019f0a VK |
69 | old_freq / 1000, volt_old ? volt_old / 1000 : -1, |
70 | new_freq / 1000, volt ? volt / 1000 : -1); | |
95ceafd4 SG |
71 | |
72 | /* scaling up? scale voltage before frequency */ | |
d4019f0a | 73 | if (!IS_ERR(cpu_reg) && new_freq > old_freq) { |
95ceafd4 SG |
74 | ret = regulator_set_voltage_tol(cpu_reg, volt, tol); |
75 | if (ret) { | |
76 | pr_err("failed to scale voltage up: %d\n", ret); | |
d4019f0a | 77 | return ret; |
95ceafd4 SG |
78 | } |
79 | } | |
80 | ||
0ca68436 | 81 | ret = clk_set_rate(cpu_clk, freq_exact); |
95ceafd4 SG |
82 | if (ret) { |
83 | pr_err("failed to set clock rate: %d\n", ret); | |
4a511de9 | 84 | if (!IS_ERR(cpu_reg)) |
95ceafd4 | 85 | regulator_set_voltage_tol(cpu_reg, volt_old, tol); |
d4019f0a | 86 | return ret; |
95ceafd4 SG |
87 | } |
88 | ||
89 | /* scaling down? scale voltage after frequency */ | |
d4019f0a | 90 | if (!IS_ERR(cpu_reg) && new_freq < old_freq) { |
95ceafd4 SG |
91 | ret = regulator_set_voltage_tol(cpu_reg, volt, tol); |
92 | if (ret) { | |
93 | pr_err("failed to scale voltage down: %d\n", ret); | |
d4019f0a | 94 | clk_set_rate(cpu_clk, old_freq * 1000); |
95ceafd4 SG |
95 | } |
96 | } | |
97 | ||
fd143b4d | 98 | return ret; |
95ceafd4 SG |
99 | } |
100 | ||
101 | static int cpu0_cpufreq_init(struct cpufreq_policy *policy) | |
102 | { | |
78b3d109 | 103 | return cpufreq_generic_init(policy, freq_table, transition_latency); |
95ceafd4 SG |
104 | } |
105 | ||
95ceafd4 SG |
106 | static struct cpufreq_driver cpu0_cpufreq_driver = { |
107 | .flags = CPUFREQ_STICKY, | |
f793d79f | 108 | .verify = cpufreq_generic_frequency_table_verify, |
9c0ebcf7 | 109 | .target_index = cpu0_set_target, |
95ceafd4 SG |
110 | .get = cpu0_get_speed, |
111 | .init = cpu0_cpufreq_init, | |
f793d79f | 112 | .exit = cpufreq_generic_exit, |
95ceafd4 | 113 | .name = "generic_cpu0", |
f793d79f | 114 | .attr = cpufreq_generic_attr, |
95ceafd4 SG |
115 | }; |
116 | ||
5553f9e2 | 117 | static int cpu0_cpufreq_probe(struct platform_device *pdev) |
95ceafd4 | 118 | { |
f837a9b5 | 119 | struct device_node *np; |
95ceafd4 SG |
120 | int ret; |
121 | ||
e1825b25 SK |
122 | cpu_dev = get_cpu_device(0); |
123 | if (!cpu_dev) { | |
124 | pr_err("failed to get cpu0 device\n"); | |
125 | return -ENODEV; | |
126 | } | |
6754f556 | 127 | |
f837a9b5 | 128 | np = of_node_get(cpu_dev->of_node); |
95ceafd4 SG |
129 | if (!np) { |
130 | pr_err("failed to find cpu0 node\n"); | |
f837a9b5 | 131 | return -ENOENT; |
95ceafd4 SG |
132 | } |
133 | ||
7d748971 | 134 | cpu_reg = devm_regulator_get_optional(cpu_dev, "cpu0"); |
fc31d6f5 NM |
135 | if (IS_ERR(cpu_reg)) { |
136 | /* | |
137 | * If cpu0 regulator supply node is present, but regulator is | |
138 | * not yet registered, we should try defering probe. | |
139 | */ | |
140 | if (PTR_ERR(cpu_reg) == -EPROBE_DEFER) { | |
141 | dev_err(cpu_dev, "cpu0 regulator not ready, retry\n"); | |
142 | ret = -EPROBE_DEFER; | |
143 | goto out_put_node; | |
144 | } | |
145 | pr_warn("failed to get cpu0 regulator: %ld\n", | |
146 | PTR_ERR(cpu_reg)); | |
fc31d6f5 NM |
147 | } |
148 | ||
5553f9e2 | 149 | cpu_clk = devm_clk_get(cpu_dev, NULL); |
95ceafd4 SG |
150 | if (IS_ERR(cpu_clk)) { |
151 | ret = PTR_ERR(cpu_clk); | |
152 | pr_err("failed to get cpu0 clock: %d\n", ret); | |
153 | goto out_put_node; | |
154 | } | |
155 | ||
95ceafd4 SG |
156 | ret = of_init_opp_table(cpu_dev); |
157 | if (ret) { | |
158 | pr_err("failed to init OPP table: %d\n", ret); | |
159 | goto out_put_node; | |
160 | } | |
161 | ||
5d4879cd | 162 | ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table); |
95ceafd4 SG |
163 | if (ret) { |
164 | pr_err("failed to init cpufreq table: %d\n", ret); | |
165 | goto out_put_node; | |
166 | } | |
167 | ||
168 | of_property_read_u32(np, "voltage-tolerance", &voltage_tolerance); | |
169 | ||
170 | if (of_property_read_u32(np, "clock-latency", &transition_latency)) | |
171 | transition_latency = CPUFREQ_ETERNAL; | |
172 | ||
43c638e3 | 173 | if (!IS_ERR(cpu_reg)) { |
47d43ba7 | 174 | struct dev_pm_opp *opp; |
95ceafd4 SG |
175 | unsigned long min_uV, max_uV; |
176 | int i; | |
177 | ||
178 | /* | |
179 | * OPP is maintained in order of increasing frequency, and | |
180 | * freq_table initialised from OPP is therefore sorted in the | |
181 | * same order. | |
182 | */ | |
183 | for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) | |
184 | ; | |
78e8eb8f | 185 | rcu_read_lock(); |
5d4879cd | 186 | opp = dev_pm_opp_find_freq_exact(cpu_dev, |
95ceafd4 | 187 | freq_table[0].frequency * 1000, true); |
5d4879cd NM |
188 | min_uV = dev_pm_opp_get_voltage(opp); |
189 | opp = dev_pm_opp_find_freq_exact(cpu_dev, | |
95ceafd4 | 190 | freq_table[i-1].frequency * 1000, true); |
5d4879cd | 191 | max_uV = dev_pm_opp_get_voltage(opp); |
78e8eb8f | 192 | rcu_read_unlock(); |
95ceafd4 SG |
193 | ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV); |
194 | if (ret > 0) | |
195 | transition_latency += ret * 1000; | |
196 | } | |
197 | ||
198 | ret = cpufreq_register_driver(&cpu0_cpufreq_driver); | |
199 | if (ret) { | |
200 | pr_err("failed register driver: %d\n", ret); | |
201 | goto out_free_table; | |
202 | } | |
203 | ||
204 | of_node_put(np); | |
205 | return 0; | |
206 | ||
207 | out_free_table: | |
5d4879cd | 208 | dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table); |
95ceafd4 SG |
209 | out_put_node: |
210 | of_node_put(np); | |
211 | return ret; | |
212 | } | |
5553f9e2 SG |
213 | |
214 | static int cpu0_cpufreq_remove(struct platform_device *pdev) | |
215 | { | |
216 | cpufreq_unregister_driver(&cpu0_cpufreq_driver); | |
5d4879cd | 217 | dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table); |
5553f9e2 SG |
218 | |
219 | return 0; | |
220 | } | |
221 | ||
222 | static struct platform_driver cpu0_cpufreq_platdrv = { | |
223 | .driver = { | |
224 | .name = "cpufreq-cpu0", | |
225 | .owner = THIS_MODULE, | |
226 | }, | |
227 | .probe = cpu0_cpufreq_probe, | |
228 | .remove = cpu0_cpufreq_remove, | |
229 | }; | |
230 | module_platform_driver(cpu0_cpufreq_platdrv); | |
95ceafd4 SG |
231 | |
232 | MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>"); | |
233 | MODULE_DESCRIPTION("Generic CPU0 cpufreq driver"); | |
234 | MODULE_LICENSE("GPL"); |