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Shawn Guo95ceafd2012-09-06 07:09:11 +00001/*
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>
Sudeep KarkadaNageshae1825b22013-09-10 18:59:46 +010015#include <linux/cpu.h>
Shawn Guo95ceafd2012-09-06 07:09:11 +000016#include <linux/cpufreq.h>
17#include <linux/err.h>
18#include <linux/module.h>
19#include <linux/of.h>
20#include <linux/opp.h>
Shawn Guo5553f9e2013-01-30 14:27:49 +000021#include <linux/platform_device.h>
Shawn Guo95ceafd2012-09-06 07:09:11 +000022#include <linux/regulator/consumer.h>
23#include <linux/slab.h>
24
25static unsigned int transition_latency;
26static unsigned int voltage_tolerance; /* in percentage */
27
28static struct device *cpu_dev;
29static struct clk *cpu_clk;
30static struct regulator *cpu_reg;
31static struct cpufreq_frequency_table *freq_table;
32
33static int cpu0_verify_speed(struct cpufreq_policy *policy)
34{
35 return cpufreq_frequency_table_verify(policy, freq_table);
36}
37
38static unsigned int cpu0_get_speed(unsigned int cpu)
39{
40 return clk_get_rate(cpu_clk) / 1000;
41}
42
43static int cpu0_set_target(struct cpufreq_policy *policy,
44 unsigned int target_freq, unsigned int relation)
45{
46 struct cpufreq_freqs freqs;
47 struct opp *opp;
jhbird.choi@samsung.com5df60552013-03-18 08:09:42 +000048 unsigned long volt = 0, volt_old = 0, tol = 0;
Guennadi Liakhovetski0ca68432013-02-25 18:22:37 +010049 long freq_Hz, freq_exact;
Viresh Kumarb43a7ff2013-03-24 11:56:43 +053050 unsigned int index;
Shawn Guo95ceafd2012-09-06 07:09:11 +000051 int ret;
52
53 ret = cpufreq_frequency_table_target(policy, freq_table, target_freq,
54 relation, &index);
55 if (ret) {
56 pr_err("failed to match target freqency %d: %d\n",
57 target_freq, ret);
58 return ret;
59 }
60
61 freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
62 if (freq_Hz < 0)
63 freq_Hz = freq_table[index].frequency * 1000;
Guennadi Liakhovetski0ca68432013-02-25 18:22:37 +010064 freq_exact = freq_Hz;
Shawn Guo95ceafd2012-09-06 07:09:11 +000065 freqs.new = freq_Hz / 1000;
66 freqs.old = clk_get_rate(cpu_clk) / 1000;
67
68 if (freqs.old == freqs.new)
69 return 0;
70
Viresh Kumarb43a7ff2013-03-24 11:56:43 +053071 cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
Shawn Guo95ceafd2012-09-06 07:09:11 +000072
Mark Brown4a511de2013-08-13 14:58:24 +020073 if (!IS_ERR(cpu_reg)) {
Nishanth Menon78e8eb82013-01-18 19:52:33 +000074 rcu_read_lock();
Shawn Guo95ceafd2012-09-06 07:09:11 +000075 opp = opp_find_freq_ceil(cpu_dev, &freq_Hz);
76 if (IS_ERR(opp)) {
Nishanth Menon78e8eb82013-01-18 19:52:33 +000077 rcu_read_unlock();
Shawn Guo95ceafd2012-09-06 07:09:11 +000078 pr_err("failed to find OPP for %ld\n", freq_Hz);
Viresh Kumarfd143b42013-04-01 12:57:44 +000079 freqs.new = freqs.old;
80 ret = PTR_ERR(opp);
81 goto post_notify;
Shawn Guo95ceafd2012-09-06 07:09:11 +000082 }
83 volt = opp_get_voltage(opp);
Nishanth Menon78e8eb82013-01-18 19:52:33 +000084 rcu_read_unlock();
Shawn Guo95ceafd2012-09-06 07:09:11 +000085 tol = volt * voltage_tolerance / 100;
86 volt_old = regulator_get_voltage(cpu_reg);
87 }
88
89 pr_debug("%u MHz, %ld mV --> %u MHz, %ld mV\n",
90 freqs.old / 1000, volt_old ? volt_old / 1000 : -1,
91 freqs.new / 1000, volt ? volt / 1000 : -1);
92
93 /* scaling up? scale voltage before frequency */
Mark Brown4a511de2013-08-13 14:58:24 +020094 if (!IS_ERR(cpu_reg) && freqs.new > freqs.old) {
Shawn Guo95ceafd2012-09-06 07:09:11 +000095 ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
96 if (ret) {
97 pr_err("failed to scale voltage up: %d\n", ret);
98 freqs.new = freqs.old;
Viresh Kumarfd143b42013-04-01 12:57:44 +000099 goto post_notify;
Shawn Guo95ceafd2012-09-06 07:09:11 +0000100 }
101 }
102
Guennadi Liakhovetski0ca68432013-02-25 18:22:37 +0100103 ret = clk_set_rate(cpu_clk, freq_exact);
Shawn Guo95ceafd2012-09-06 07:09:11 +0000104 if (ret) {
105 pr_err("failed to set clock rate: %d\n", ret);
Mark Brown4a511de2013-08-13 14:58:24 +0200106 if (!IS_ERR(cpu_reg))
Shawn Guo95ceafd2012-09-06 07:09:11 +0000107 regulator_set_voltage_tol(cpu_reg, volt_old, tol);
Viresh Kumarfd143b42013-04-01 12:57:44 +0000108 freqs.new = freqs.old;
109 goto post_notify;
Shawn Guo95ceafd2012-09-06 07:09:11 +0000110 }
111
112 /* scaling down? scale voltage after frequency */
Mark Brown4a511de2013-08-13 14:58:24 +0200113 if (!IS_ERR(cpu_reg) && freqs.new < freqs.old) {
Shawn Guo95ceafd2012-09-06 07:09:11 +0000114 ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
115 if (ret) {
116 pr_err("failed to scale voltage down: %d\n", ret);
117 clk_set_rate(cpu_clk, freqs.old * 1000);
118 freqs.new = freqs.old;
Shawn Guo95ceafd2012-09-06 07:09:11 +0000119 }
120 }
121
Viresh Kumarfd143b42013-04-01 12:57:44 +0000122post_notify:
Viresh Kumarb43a7ff2013-03-24 11:56:43 +0530123 cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
Shawn Guo95ceafd2012-09-06 07:09:11 +0000124
Viresh Kumarfd143b42013-04-01 12:57:44 +0000125 return ret;
Shawn Guo95ceafd2012-09-06 07:09:11 +0000126}
127
128static int cpu0_cpufreq_init(struct cpufreq_policy *policy)
129{
130 int ret;
131
Shawn Guo95ceafd2012-09-06 07:09:11 +0000132 ret = cpufreq_frequency_table_cpuinfo(policy, freq_table);
133 if (ret) {
134 pr_err("invalid frequency table: %d\n", ret);
135 return ret;
136 }
137
138 policy->cpuinfo.transition_latency = transition_latency;
139 policy->cur = clk_get_rate(cpu_clk) / 1000;
140
141 /*
142 * The driver only supports the SMP configuartion where all processors
143 * share the clock and voltage and clock. Use cpufreq affected_cpus
144 * interface to have all CPUs scaled together.
145 */
Shawn Guo95ceafd2012-09-06 07:09:11 +0000146 cpumask_setall(policy->cpus);
147
148 cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
149
150 return 0;
151}
152
153static int cpu0_cpufreq_exit(struct cpufreq_policy *policy)
154{
155 cpufreq_frequency_table_put_attr(policy->cpu);
156
157 return 0;
158}
159
160static struct freq_attr *cpu0_cpufreq_attr[] = {
161 &cpufreq_freq_attr_scaling_available_freqs,
162 NULL,
163};
164
165static struct cpufreq_driver cpu0_cpufreq_driver = {
166 .flags = CPUFREQ_STICKY,
167 .verify = cpu0_verify_speed,
168 .target = cpu0_set_target,
169 .get = cpu0_get_speed,
170 .init = cpu0_cpufreq_init,
171 .exit = cpu0_cpufreq_exit,
172 .name = "generic_cpu0",
173 .attr = cpu0_cpufreq_attr,
174};
175
Shawn Guo5553f9e2013-01-30 14:27:49 +0000176static int cpu0_cpufreq_probe(struct platform_device *pdev)
Shawn Guo95ceafd2012-09-06 07:09:11 +0000177{
Sudeep KarkadaNageshaf837a9b2013-06-17 15:04:19 +0100178 struct device_node *np;
Shawn Guo95ceafd2012-09-06 07:09:11 +0000179 int ret;
180
Sudeep KarkadaNageshae1825b22013-09-10 18:59:46 +0100181 cpu_dev = get_cpu_device(0);
182 if (!cpu_dev) {
183 pr_err("failed to get cpu0 device\n");
184 return -ENODEV;
185 }
Paolo Pisatif5c3ef22013-03-28 09:24:29 +0000186
Sudeep KarkadaNageshaf837a9b2013-06-17 15:04:19 +0100187 np = of_node_get(cpu_dev->of_node);
Shawn Guo95ceafd2012-09-06 07:09:11 +0000188 if (!np) {
189 pr_err("failed to find cpu0 node\n");
Sudeep KarkadaNageshaf837a9b2013-06-17 15:04:19 +0100190 return -ENOENT;
Shawn Guo95ceafd2012-09-06 07:09:11 +0000191 }
192
Mark Brown7d748972013-08-09 19:07:12 +0100193 cpu_reg = devm_regulator_get_optional(cpu_dev, "cpu0");
Nishanth Menonfc31d6f2013-05-01 13:38:12 +0000194 if (IS_ERR(cpu_reg)) {
195 /*
196 * If cpu0 regulator supply node is present, but regulator is
197 * not yet registered, we should try defering probe.
198 */
199 if (PTR_ERR(cpu_reg) == -EPROBE_DEFER) {
200 dev_err(cpu_dev, "cpu0 regulator not ready, retry\n");
201 ret = -EPROBE_DEFER;
202 goto out_put_node;
203 }
204 pr_warn("failed to get cpu0 regulator: %ld\n",
205 PTR_ERR(cpu_reg));
Nishanth Menonfc31d6f2013-05-01 13:38:12 +0000206 }
207
Shawn Guo5553f9e2013-01-30 14:27:49 +0000208 cpu_clk = devm_clk_get(cpu_dev, NULL);
Shawn Guo95ceafd2012-09-06 07:09:11 +0000209 if (IS_ERR(cpu_clk)) {
210 ret = PTR_ERR(cpu_clk);
211 pr_err("failed to get cpu0 clock: %d\n", ret);
212 goto out_put_node;
213 }
214
Shawn Guo95ceafd2012-09-06 07:09:11 +0000215 ret = of_init_opp_table(cpu_dev);
216 if (ret) {
217 pr_err("failed to init OPP table: %d\n", ret);
218 goto out_put_node;
219 }
220
221 ret = opp_init_cpufreq_table(cpu_dev, &freq_table);
222 if (ret) {
223 pr_err("failed to init cpufreq table: %d\n", ret);
224 goto out_put_node;
225 }
226
227 of_property_read_u32(np, "voltage-tolerance", &voltage_tolerance);
228
229 if (of_property_read_u32(np, "clock-latency", &transition_latency))
230 transition_latency = CPUFREQ_ETERNAL;
231
Philipp Zabel43c638e2013-09-26 11:19:37 +0200232 if (!IS_ERR(cpu_reg)) {
Shawn Guo95ceafd2012-09-06 07:09:11 +0000233 struct opp *opp;
234 unsigned long min_uV, max_uV;
235 int i;
236
237 /*
238 * OPP is maintained in order of increasing frequency, and
239 * freq_table initialised from OPP is therefore sorted in the
240 * same order.
241 */
242 for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++)
243 ;
Nishanth Menon78e8eb82013-01-18 19:52:33 +0000244 rcu_read_lock();
Shawn Guo95ceafd2012-09-06 07:09:11 +0000245 opp = opp_find_freq_exact(cpu_dev,
246 freq_table[0].frequency * 1000, true);
247 min_uV = opp_get_voltage(opp);
248 opp = opp_find_freq_exact(cpu_dev,
249 freq_table[i-1].frequency * 1000, true);
250 max_uV = opp_get_voltage(opp);
Nishanth Menon78e8eb82013-01-18 19:52:33 +0000251 rcu_read_unlock();
Shawn Guo95ceafd2012-09-06 07:09:11 +0000252 ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV);
253 if (ret > 0)
254 transition_latency += ret * 1000;
255 }
256
257 ret = cpufreq_register_driver(&cpu0_cpufreq_driver);
258 if (ret) {
259 pr_err("failed register driver: %d\n", ret);
260 goto out_free_table;
261 }
262
263 of_node_put(np);
264 return 0;
265
266out_free_table:
267 opp_free_cpufreq_table(cpu_dev, &freq_table);
268out_put_node:
269 of_node_put(np);
270 return ret;
271}
Shawn Guo5553f9e2013-01-30 14:27:49 +0000272
273static int cpu0_cpufreq_remove(struct platform_device *pdev)
274{
275 cpufreq_unregister_driver(&cpu0_cpufreq_driver);
276 opp_free_cpufreq_table(cpu_dev, &freq_table);
277
278 return 0;
279}
280
281static struct platform_driver cpu0_cpufreq_platdrv = {
282 .driver = {
283 .name = "cpufreq-cpu0",
284 .owner = THIS_MODULE,
285 },
286 .probe = cpu0_cpufreq_probe,
287 .remove = cpu0_cpufreq_remove,
288};
289module_platform_driver(cpu0_cpufreq_platdrv);
Shawn Guo95ceafd2012-09-06 07:09:11 +0000290
291MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
292MODULE_DESCRIPTION("Generic CPU0 cpufreq driver");
293MODULE_LICENSE("GPL");