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 */
40 static struct freq_attr *cpufreq_dt_attr[] = {
41 &cpufreq_freq_attr_scaling_available_freqs,
42 NULL, /* Extra space for boost-attr if required */
46 static int set_target(struct cpufreq_policy *policy, unsigned int index)
48 struct dev_pm_opp *opp;
49 struct cpufreq_frequency_table *freq_table = policy->freq_table;
50 struct clk *cpu_clk = policy->clk;
51 struct private_data *priv = policy->driver_data;
52 struct device *cpu_dev = priv->cpu_dev;
53 struct regulator *cpu_reg = priv->cpu_reg;
54 unsigned long volt = 0, tol = 0;
56 unsigned int old_freq, new_freq;
57 long freq_Hz, freq_exact;
60 freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
62 freq_Hz = freq_table[index].frequency * 1000;
65 new_freq = freq_Hz / 1000;
66 old_freq = clk_get_rate(cpu_clk) / 1000;
68 if (!IS_ERR(cpu_reg)) {
69 unsigned long opp_freq;
72 opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_Hz);
75 dev_err(cpu_dev, "failed to find OPP for %ld\n",
79 volt = dev_pm_opp_get_voltage(opp);
80 opp_freq = dev_pm_opp_get_freq(opp);
82 tol = volt * priv->voltage_tolerance / 100;
83 volt_old = regulator_get_voltage(cpu_reg);
84 dev_dbg(cpu_dev, "Found OPP: %ld kHz, %ld uV\n",
85 opp_freq / 1000, volt);
88 dev_dbg(cpu_dev, "%u MHz, %d mV --> %u MHz, %ld mV\n",
89 old_freq / 1000, (volt_old > 0) ? volt_old / 1000 : -1,
90 new_freq / 1000, volt ? volt / 1000 : -1);
92 /* scaling up? scale voltage before frequency */
93 if (!IS_ERR(cpu_reg) && new_freq > old_freq) {
94 ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
96 dev_err(cpu_dev, "failed to scale voltage up: %d\n",
102 ret = clk_set_rate(cpu_clk, freq_exact);
104 dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
105 if (!IS_ERR(cpu_reg) && volt_old > 0)
106 regulator_set_voltage_tol(cpu_reg, volt_old, tol);
110 /* scaling down? scale voltage after frequency */
111 if (!IS_ERR(cpu_reg) && new_freq < old_freq) {
112 ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
114 dev_err(cpu_dev, "failed to scale voltage down: %d\n",
116 clk_set_rate(cpu_clk, old_freq * 1000);
124 * An earlier version of opp-v1 bindings used to name the regulator
125 * "cpu0-supply", we still need to handle that for backwards compatibility.
127 static const char *find_supply_name(struct device *dev, struct device_node *np)
132 /* Try "cpu0" for older DTs */
134 pp = of_find_property(np, "cpu0-supply", NULL);
139 pp = of_find_property(np, "cpu-supply", NULL);
143 dev_dbg(dev, "no regulator for cpu%d\n", cpu);
147 static int allocate_resources(int cpu, struct device **cdev,
148 struct regulator **creg, struct clk **cclk)
150 struct device *cpu_dev;
151 struct regulator *cpu_reg;
154 char *reg_cpu0 = "cpu0", *reg_cpu = "cpu", *reg;
156 cpu_dev = get_cpu_device(cpu);
158 pr_err("failed to get cpu%d device\n", cpu);
162 /* Try "cpu0" for older DTs */
169 cpu_reg = regulator_get_optional(cpu_dev, reg);
170 ret = PTR_ERR_OR_ZERO(cpu_reg);
173 * If cpu's regulator supply node is present, but regulator is
174 * not yet registered, we should try defering probe.
176 if (ret == -EPROBE_DEFER) {
177 dev_dbg(cpu_dev, "cpu%d regulator not ready, retry\n",
182 /* Try with "cpu-supply" */
183 if (reg == reg_cpu0) {
188 dev_dbg(cpu_dev, "no regulator for cpu%d: %d\n", cpu, ret);
191 cpu_clk = clk_get(cpu_dev, NULL);
192 ret = PTR_ERR_OR_ZERO(cpu_clk);
195 if (!IS_ERR(cpu_reg))
196 regulator_put(cpu_reg);
199 * If cpu's clk node is present, but clock is not yet
200 * registered, we should try defering probe.
202 if (ret == -EPROBE_DEFER)
203 dev_dbg(cpu_dev, "cpu%d clock not ready, retry\n", cpu);
205 dev_err(cpu_dev, "failed to get cpu%d clock: %d\n", cpu,
216 static int cpufreq_init(struct cpufreq_policy *policy)
218 struct cpufreq_frequency_table *freq_table;
219 struct device_node *np;
220 struct private_data *priv;
221 struct device *cpu_dev;
222 struct regulator *cpu_reg;
224 struct dev_pm_opp *suspend_opp;
225 unsigned int transition_latency;
230 ret = allocate_resources(policy->cpu, &cpu_dev, &cpu_reg, &cpu_clk);
232 pr_err("%s: Failed to allocate resources: %d\n", __func__, ret);
236 np = of_node_get(cpu_dev->of_node);
238 dev_err(cpu_dev, "failed to find cpu%d node\n", policy->cpu);
240 goto out_put_reg_clk;
243 /* Get OPP-sharing information from "operating-points-v2" bindings */
244 ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, policy->cpus);
247 * operating-points-v2 not supported, fallback to old method of
248 * finding shared-OPPs for backward compatibility.
257 * OPP layer will be taking care of regulators now, but it needs to know
258 * the name of the regulator first.
260 name = find_supply_name(cpu_dev, np);
262 ret = dev_pm_opp_set_regulator(cpu_dev, name);
264 dev_err(cpu_dev, "Failed to set regulator for cpu%d: %d\n",
271 * Initialize OPP tables for all policy->cpus. They will be shared by
272 * all CPUs which have marked their CPUs shared with OPP bindings.
274 * For platforms not using operating-points-v2 bindings, we do this
275 * before updating policy->cpus. Otherwise, we will end up creating
276 * duplicate OPPs for policy->cpus.
278 * OPPs might be populated at runtime, don't check for error here
280 dev_pm_opp_of_cpumask_add_table(policy->cpus);
283 * But we need OPP table to function so if it is not there let's
284 * give platform code chance to provide it for us.
286 ret = dev_pm_opp_get_opp_count(cpu_dev);
288 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
294 struct cpufreq_dt_platform_data *pd = cpufreq_get_driver_data();
296 if (!pd || !pd->independent_clocks)
297 cpumask_setall(policy->cpus);
300 * OPP tables are initialized only for policy->cpu, do it for
303 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
305 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
309 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
315 priv->reg_name = name;
316 of_property_read_u32(np, "voltage-tolerance", &priv->voltage_tolerance);
318 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
320 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
324 priv->cpu_dev = cpu_dev;
325 priv->cpu_reg = cpu_reg;
326 policy->driver_data = priv;
328 policy->clk = cpu_clk;
331 suspend_opp = dev_pm_opp_get_suspend_opp(cpu_dev);
333 policy->suspend_freq = dev_pm_opp_get_freq(suspend_opp) / 1000;
336 ret = cpufreq_table_validate_and_show(policy, freq_table);
338 dev_err(cpu_dev, "%s: invalid frequency table: %d\n", __func__,
340 goto out_free_cpufreq_table;
343 /* Support turbo/boost mode */
344 if (policy_has_boost_freq(policy)) {
345 /* This gets disabled by core on driver unregister */
346 ret = cpufreq_enable_boost_support();
348 goto out_free_cpufreq_table;
349 cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
352 transition_latency = dev_pm_opp_get_max_transition_latency(cpu_dev);
353 if (!transition_latency)
354 transition_latency = CPUFREQ_ETERNAL;
356 policy->cpuinfo.transition_latency = transition_latency;
362 out_free_cpufreq_table:
363 dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
367 dev_pm_opp_of_cpumask_remove_table(policy->cpus);
369 dev_pm_opp_put_regulator(cpu_dev);
374 if (!IS_ERR(cpu_reg))
375 regulator_put(cpu_reg);
380 static int cpufreq_exit(struct cpufreq_policy *policy)
382 struct private_data *priv = policy->driver_data;
384 cpufreq_cooling_unregister(priv->cdev);
385 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
386 dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
388 dev_pm_opp_put_regulator(priv->cpu_dev);
390 clk_put(policy->clk);
391 if (!IS_ERR(priv->cpu_reg))
392 regulator_put(priv->cpu_reg);
398 static void cpufreq_ready(struct cpufreq_policy *policy)
400 struct private_data *priv = policy->driver_data;
401 struct device_node *np = of_node_get(priv->cpu_dev->of_node);
407 * For now, just loading the cooling device;
408 * thermal DT code takes care of matching them.
410 if (of_find_property(np, "#cooling-cells", NULL)) {
411 u32 power_coefficient = 0;
413 of_property_read_u32(np, "dynamic-power-coefficient",
416 priv->cdev = of_cpufreq_power_cooling_register(np,
417 policy->related_cpus, power_coefficient, NULL);
418 if (IS_ERR(priv->cdev)) {
419 dev_err(priv->cpu_dev,
420 "running cpufreq without cooling device: %ld\n",
421 PTR_ERR(priv->cdev));
430 static struct cpufreq_driver dt_cpufreq_driver = {
431 .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
432 .verify = cpufreq_generic_frequency_table_verify,
433 .target_index = set_target,
434 .get = cpufreq_generic_get,
435 .init = cpufreq_init,
436 .exit = cpufreq_exit,
437 .ready = cpufreq_ready,
438 .name = "cpufreq-dt",
439 .attr = cpufreq_dt_attr,
440 .suspend = cpufreq_generic_suspend,
443 static int dt_cpufreq_probe(struct platform_device *pdev)
445 struct device *cpu_dev;
446 struct regulator *cpu_reg;
451 * All per-cluster (CPUs sharing clock/voltages) initialization is done
452 * from ->init(). In probe(), we just need to make sure that clk and
453 * regulators are available. Else defer probe and retry.
455 * FIXME: Is checking this only for CPU0 sufficient ?
457 ret = allocate_resources(0, &cpu_dev, &cpu_reg, &cpu_clk);
462 if (!IS_ERR(cpu_reg))
463 regulator_put(cpu_reg);
465 dt_cpufreq_driver.driver_data = dev_get_platdata(&pdev->dev);
467 ret = cpufreq_register_driver(&dt_cpufreq_driver);
469 dev_err(cpu_dev, "failed register driver: %d\n", ret);
474 static int dt_cpufreq_remove(struct platform_device *pdev)
476 cpufreq_unregister_driver(&dt_cpufreq_driver);
480 static struct platform_driver dt_cpufreq_platdrv = {
482 .name = "cpufreq-dt",
484 .probe = dt_cpufreq_probe,
485 .remove = dt_cpufreq_remove,
487 module_platform_driver(dt_cpufreq_platdrv);
489 MODULE_ALIAS("platform:cpufreq-dt");
490 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
491 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
492 MODULE_DESCRIPTION("Generic cpufreq driver");
493 MODULE_LICENSE("GPL");