2 * Copyright (C) 2012 Freescale Semiconductor, Inc.
4 * Copyright (C) 2014 Linaro.
5 * Viresh Kumar <viresh.kumar@linaro.org>
7 * The OPP code in function set_target() is reused from
8 * drivers/cpufreq/omap-cpufreq.c
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
15 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17 #include <linux/clk.h>
18 #include <linux/cpu.h>
19 #include <linux/cpu_cooling.h>
20 #include <linux/cpufreq.h>
21 #include <linux/cpufreq-dt.h>
22 #include <linux/cpumask.h>
23 #include <linux/err.h>
24 #include <linux/module.h>
26 #include <linux/pm_opp.h>
27 #include <linux/platform_device.h>
28 #include <linux/regulator/consumer.h>
29 #include <linux/slab.h>
30 #include <linux/thermal.h>
33 struct device *cpu_dev;
34 struct regulator *cpu_reg;
35 struct thermal_cooling_device *cdev;
36 unsigned int voltage_tolerance; /* in percentage */
39 static int set_target(struct cpufreq_policy *policy, unsigned int index)
41 struct dev_pm_opp *opp;
42 struct cpufreq_frequency_table *freq_table = policy->freq_table;
43 struct clk *cpu_clk = policy->clk;
44 struct private_data *priv = policy->driver_data;
45 struct device *cpu_dev = priv->cpu_dev;
46 struct regulator *cpu_reg = priv->cpu_reg;
47 unsigned long volt = 0, volt_old = 0, tol = 0;
48 unsigned int old_freq, new_freq;
49 long freq_Hz, freq_exact;
52 freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
54 freq_Hz = freq_table[index].frequency * 1000;
57 new_freq = freq_Hz / 1000;
58 old_freq = clk_get_rate(cpu_clk) / 1000;
60 if (!IS_ERR(cpu_reg)) {
61 unsigned long opp_freq;
64 opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_Hz);
67 dev_err(cpu_dev, "failed to find OPP for %ld\n",
71 volt = dev_pm_opp_get_voltage(opp);
72 opp_freq = dev_pm_opp_get_freq(opp);
74 tol = volt * priv->voltage_tolerance / 100;
75 volt_old = regulator_get_voltage(cpu_reg);
76 dev_dbg(cpu_dev, "Found OPP: %ld kHz, %ld uV\n",
77 opp_freq / 1000, volt);
80 dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n",
81 old_freq / 1000, (volt_old > 0) ? volt_old / 1000 : -1,
82 new_freq / 1000, volt ? volt / 1000 : -1);
84 /* scaling up? scale voltage before frequency */
85 if (!IS_ERR(cpu_reg) && new_freq > old_freq) {
86 ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
88 dev_err(cpu_dev, "failed to scale voltage up: %d\n",
94 ret = clk_set_rate(cpu_clk, freq_exact);
96 dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
97 if (!IS_ERR(cpu_reg) && volt_old > 0)
98 regulator_set_voltage_tol(cpu_reg, volt_old, tol);
102 /* scaling down? scale voltage after frequency */
103 if (!IS_ERR(cpu_reg) && new_freq < old_freq) {
104 ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
106 dev_err(cpu_dev, "failed to scale voltage down: %d\n",
108 clk_set_rate(cpu_clk, old_freq * 1000);
115 static int allocate_resources(int cpu, struct device **cdev,
116 struct regulator **creg, struct clk **cclk)
118 struct device *cpu_dev;
119 struct regulator *cpu_reg;
122 char *reg_cpu0 = "cpu0", *reg_cpu = "cpu", *reg;
124 cpu_dev = get_cpu_device(cpu);
126 pr_err("failed to get cpu%d device\n", cpu);
130 /* Try "cpu0" for older DTs */
137 cpu_reg = regulator_get_optional(cpu_dev, reg);
138 if (IS_ERR(cpu_reg)) {
140 * If cpu's regulator supply node is present, but regulator is
141 * not yet registered, we should try defering probe.
143 if (PTR_ERR(cpu_reg) == -EPROBE_DEFER) {
144 dev_dbg(cpu_dev, "cpu%d regulator not ready, retry\n",
146 return -EPROBE_DEFER;
149 /* Try with "cpu-supply" */
150 if (reg == reg_cpu0) {
155 dev_dbg(cpu_dev, "no regulator for cpu%d: %ld\n",
156 cpu, PTR_ERR(cpu_reg));
159 cpu_clk = clk_get(cpu_dev, NULL);
160 if (IS_ERR(cpu_clk)) {
162 if (!IS_ERR(cpu_reg))
163 regulator_put(cpu_reg);
165 ret = PTR_ERR(cpu_clk);
168 * If cpu's clk node is present, but clock is not yet
169 * registered, we should try defering probe.
171 if (ret == -EPROBE_DEFER)
172 dev_dbg(cpu_dev, "cpu%d clock not ready, retry\n", cpu);
174 dev_err(cpu_dev, "failed to get cpu%d clock: %d\n", cpu,
185 static int cpufreq_init(struct cpufreq_policy *policy)
187 struct cpufreq_dt_platform_data *pd;
188 struct cpufreq_frequency_table *freq_table;
189 struct device_node *np;
190 struct private_data *priv;
191 struct device *cpu_dev;
192 struct regulator *cpu_reg;
194 unsigned long min_uV = ~0, max_uV = 0;
195 unsigned int transition_latency;
198 ret = allocate_resources(policy->cpu, &cpu_dev, &cpu_reg, &cpu_clk);
200 pr_err("%s: Failed to allocate resources: %d\n", __func__, ret);
204 np = of_node_get(cpu_dev->of_node);
206 dev_err(cpu_dev, "failed to find cpu%d node\n", policy->cpu);
208 goto out_put_reg_clk;
211 /* OPPs might be populated at runtime, don't check for error here */
212 of_init_opp_table(cpu_dev);
214 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
220 of_property_read_u32(np, "voltage-tolerance", &priv->voltage_tolerance);
222 if (of_property_read_u32(np, "clock-latency", &transition_latency))
223 transition_latency = CPUFREQ_ETERNAL;
225 if (!IS_ERR(cpu_reg)) {
226 unsigned long opp_freq = 0;
229 * Disable any OPPs where the connected regulator isn't able to
230 * provide the specified voltage and record minimum and maximum
234 struct dev_pm_opp *opp;
235 unsigned long opp_uV, tol_uV;
238 opp = dev_pm_opp_find_freq_ceil(cpu_dev, &opp_freq);
243 opp_uV = dev_pm_opp_get_voltage(opp);
246 tol_uV = opp_uV * priv->voltage_tolerance / 100;
247 if (regulator_is_supported_voltage(cpu_reg, opp_uV,
254 dev_pm_opp_disable(cpu_dev, opp_freq);
260 ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV);
262 transition_latency += ret * 1000;
265 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
267 pr_err("failed to init cpufreq table: %d\n", ret);
271 priv->cpu_dev = cpu_dev;
272 priv->cpu_reg = cpu_reg;
273 policy->driver_data = priv;
275 policy->clk = cpu_clk;
276 ret = cpufreq_table_validate_and_show(policy, freq_table);
278 dev_err(cpu_dev, "%s: invalid frequency table: %d\n", __func__,
280 goto out_free_cpufreq_table;
283 policy->cpuinfo.transition_latency = transition_latency;
285 pd = cpufreq_get_driver_data();
286 if (!pd || !pd->independent_clocks)
287 cpumask_setall(policy->cpus);
293 out_free_cpufreq_table:
294 dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
298 of_free_opp_table(cpu_dev);
302 if (!IS_ERR(cpu_reg))
303 regulator_put(cpu_reg);
308 static int cpufreq_exit(struct cpufreq_policy *policy)
310 struct private_data *priv = policy->driver_data;
313 cpufreq_cooling_unregister(priv->cdev);
314 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
315 of_free_opp_table(priv->cpu_dev);
316 clk_put(policy->clk);
317 if (!IS_ERR(priv->cpu_reg))
318 regulator_put(priv->cpu_reg);
324 static void cpufreq_ready(struct cpufreq_policy *policy)
326 struct private_data *priv = policy->driver_data;
327 struct device_node *np = of_node_get(priv->cpu_dev->of_node);
333 * For now, just loading the cooling device;
334 * thermal DT code takes care of matching them.
336 if (of_find_property(np, "#cooling-cells", NULL)) {
337 priv->cdev = of_cpufreq_cooling_register(np,
338 policy->related_cpus);
339 if (IS_ERR(priv->cdev)) {
340 dev_err(priv->cpu_dev,
341 "running cpufreq without cooling device: %ld\n",
342 PTR_ERR(priv->cdev));
351 static struct cpufreq_driver dt_cpufreq_driver = {
352 .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
353 .verify = cpufreq_generic_frequency_table_verify,
354 .target_index = set_target,
355 .get = cpufreq_generic_get,
356 .init = cpufreq_init,
357 .exit = cpufreq_exit,
358 .ready = cpufreq_ready,
359 .name = "cpufreq-dt",
360 .attr = cpufreq_generic_attr,
363 static int dt_cpufreq_probe(struct platform_device *pdev)
365 struct device *cpu_dev;
366 struct regulator *cpu_reg;
371 * All per-cluster (CPUs sharing clock/voltages) initialization is done
372 * from ->init(). In probe(), we just need to make sure that clk and
373 * regulators are available. Else defer probe and retry.
375 * FIXME: Is checking this only for CPU0 sufficient ?
377 ret = allocate_resources(0, &cpu_dev, &cpu_reg, &cpu_clk);
382 if (!IS_ERR(cpu_reg))
383 regulator_put(cpu_reg);
385 dt_cpufreq_driver.driver_data = dev_get_platdata(&pdev->dev);
387 ret = cpufreq_register_driver(&dt_cpufreq_driver);
389 dev_err(cpu_dev, "failed register driver: %d\n", ret);
394 static int dt_cpufreq_remove(struct platform_device *pdev)
396 cpufreq_unregister_driver(&dt_cpufreq_driver);
400 static struct platform_driver dt_cpufreq_platdrv = {
402 .name = "cpufreq-dt",
403 .owner = THIS_MODULE,
405 .probe = dt_cpufreq_probe,
406 .remove = dt_cpufreq_remove,
408 module_platform_driver(dt_cpufreq_platdrv);
410 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
411 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
412 MODULE_DESCRIPTION("Generic cpufreq driver");
413 MODULE_LICENSE("GPL");