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 struct freq_attr *cpufreq_dt_attr[] = {
40 &cpufreq_freq_attr_scaling_available_freqs,
41 NULL, /* Extra space for boost-attr if required */
45 static int set_target(struct cpufreq_policy *policy, unsigned int index)
47 struct dev_pm_opp *opp;
48 struct cpufreq_frequency_table *freq_table = policy->freq_table;
49 struct clk *cpu_clk = policy->clk;
50 struct private_data *priv = policy->driver_data;
51 struct device *cpu_dev = priv->cpu_dev;
52 struct regulator *cpu_reg = priv->cpu_reg;
53 unsigned long volt = 0, volt_old = 0, tol = 0;
54 unsigned int old_freq, new_freq;
55 long freq_Hz, freq_exact;
58 freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
60 freq_Hz = freq_table[index].frequency * 1000;
63 new_freq = freq_Hz / 1000;
64 old_freq = clk_get_rate(cpu_clk) / 1000;
66 if (!IS_ERR(cpu_reg)) {
67 unsigned long opp_freq;
70 opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_Hz);
73 dev_err(cpu_dev, "failed to find OPP for %ld\n",
77 volt = dev_pm_opp_get_voltage(opp);
78 opp_freq = dev_pm_opp_get_freq(opp);
80 tol = volt * priv->voltage_tolerance / 100;
81 volt_old = regulator_get_voltage(cpu_reg);
82 dev_dbg(cpu_dev, "Found OPP: %ld kHz, %ld uV\n",
83 opp_freq / 1000, volt);
86 dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n",
87 old_freq / 1000, (volt_old > 0) ? volt_old / 1000 : -1,
88 new_freq / 1000, volt ? volt / 1000 : -1);
90 /* scaling up? scale voltage before frequency */
91 if (!IS_ERR(cpu_reg) && new_freq > old_freq) {
92 ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
94 dev_err(cpu_dev, "failed to scale voltage up: %d\n",
100 ret = clk_set_rate(cpu_clk, freq_exact);
102 dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
103 if (!IS_ERR(cpu_reg) && volt_old > 0)
104 regulator_set_voltage_tol(cpu_reg, volt_old, tol);
108 /* scaling down? scale voltage after frequency */
109 if (!IS_ERR(cpu_reg) && new_freq < old_freq) {
110 ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
112 dev_err(cpu_dev, "failed to scale voltage down: %d\n",
114 clk_set_rate(cpu_clk, old_freq * 1000);
121 static int allocate_resources(int cpu, struct device **cdev,
122 struct regulator **creg, struct clk **cclk)
124 struct device *cpu_dev;
125 struct regulator *cpu_reg;
128 char *reg_cpu0 = "cpu0", *reg_cpu = "cpu", *reg;
130 cpu_dev = get_cpu_device(cpu);
132 pr_err("failed to get cpu%d device\n", cpu);
136 /* Try "cpu0" for older DTs */
143 cpu_reg = regulator_get_optional(cpu_dev, reg);
144 if (IS_ERR(cpu_reg)) {
146 * If cpu's regulator supply node is present, but regulator is
147 * not yet registered, we should try defering probe.
149 if (PTR_ERR(cpu_reg) == -EPROBE_DEFER) {
150 dev_dbg(cpu_dev, "cpu%d regulator not ready, retry\n",
152 return -EPROBE_DEFER;
155 /* Try with "cpu-supply" */
156 if (reg == reg_cpu0) {
161 dev_dbg(cpu_dev, "no regulator for cpu%d: %ld\n",
162 cpu, PTR_ERR(cpu_reg));
165 cpu_clk = clk_get(cpu_dev, NULL);
166 if (IS_ERR(cpu_clk)) {
168 if (!IS_ERR(cpu_reg))
169 regulator_put(cpu_reg);
171 ret = PTR_ERR(cpu_clk);
174 * If cpu's clk node is present, but clock is not yet
175 * registered, we should try defering probe.
177 if (ret == -EPROBE_DEFER)
178 dev_dbg(cpu_dev, "cpu%d clock not ready, retry\n", cpu);
180 dev_err(cpu_dev, "failed to get cpu%d clock: %d\n", cpu,
191 static int cpufreq_init(struct cpufreq_policy *policy)
193 struct cpufreq_frequency_table *freq_table;
194 struct device_node *np;
195 struct private_data *priv;
196 struct device *cpu_dev;
197 struct regulator *cpu_reg;
199 unsigned long min_uV = ~0, max_uV = 0;
200 unsigned int transition_latency;
201 bool need_update = false;
204 ret = allocate_resources(policy->cpu, &cpu_dev, &cpu_reg, &cpu_clk);
206 pr_err("%s: Failed to allocate resources: %d\n", __func__, ret);
210 np = of_node_get(cpu_dev->of_node);
212 dev_err(cpu_dev, "failed to find cpu%d node\n", policy->cpu);
214 goto out_put_reg_clk;
217 /* Get OPP-sharing information from "operating-points-v2" bindings */
218 ret = of_get_cpus_sharing_opps(cpu_dev, policy->cpus);
221 * operating-points-v2 not supported, fallback to old method of
222 * finding shared-OPPs for backward compatibility.
231 * Initialize OPP tables for all policy->cpus. They will be shared by
232 * all CPUs which have marked their CPUs shared with OPP bindings.
234 * For platforms not using operating-points-v2 bindings, we do this
235 * before updating policy->cpus. Otherwise, we will end up creating
236 * duplicate OPPs for policy->cpus.
238 * OPPs might be populated at runtime, don't check for error here
240 of_cpumask_init_opp_table(policy->cpus);
243 struct cpufreq_dt_platform_data *pd = cpufreq_get_driver_data();
245 if (!pd || !pd->independent_clocks)
246 cpumask_setall(policy->cpus);
249 * OPP tables are initialized only for policy->cpu, do it for
252 set_cpus_sharing_opps(cpu_dev, policy->cpus);
254 of_property_read_u32(np, "clock-latency", &transition_latency);
256 transition_latency = dev_pm_opp_get_max_clock_latency(cpu_dev);
260 * But we need OPP table to function so if it is not there let's
261 * give platform code chance to provide it for us.
263 ret = dev_pm_opp_get_opp_count(cpu_dev);
265 pr_debug("OPP table is not ready, deferring probe\n");
270 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
276 of_property_read_u32(np, "voltage-tolerance", &priv->voltage_tolerance);
278 if (!transition_latency)
279 transition_latency = CPUFREQ_ETERNAL;
281 if (!IS_ERR(cpu_reg)) {
282 unsigned long opp_freq = 0;
285 * Disable any OPPs where the connected regulator isn't able to
286 * provide the specified voltage and record minimum and maximum
290 struct dev_pm_opp *opp;
291 unsigned long opp_uV, tol_uV;
294 opp = dev_pm_opp_find_freq_ceil(cpu_dev, &opp_freq);
299 opp_uV = dev_pm_opp_get_voltage(opp);
302 tol_uV = opp_uV * priv->voltage_tolerance / 100;
303 if (regulator_is_supported_voltage(cpu_reg, opp_uV,
310 dev_pm_opp_disable(cpu_dev, opp_freq);
316 ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV);
318 transition_latency += ret * 1000;
321 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
323 pr_err("failed to init cpufreq table: %d\n", ret);
327 priv->cpu_dev = cpu_dev;
328 priv->cpu_reg = cpu_reg;
329 policy->driver_data = priv;
331 policy->clk = cpu_clk;
332 ret = cpufreq_table_validate_and_show(policy, freq_table);
334 dev_err(cpu_dev, "%s: invalid frequency table: %d\n", __func__,
336 goto out_free_cpufreq_table;
339 /* Support turbo/boost mode */
340 if (policy_has_boost_freq(policy)) {
341 /* This gets disabled by core on driver unregister */
342 ret = cpufreq_enable_boost_support();
344 goto out_free_cpufreq_table;
345 cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
348 policy->cpuinfo.transition_latency = transition_latency;
354 out_free_cpufreq_table:
355 dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
359 of_cpumask_free_opp_table(policy->cpus);
364 if (!IS_ERR(cpu_reg))
365 regulator_put(cpu_reg);
370 static int cpufreq_exit(struct cpufreq_policy *policy)
372 struct private_data *priv = policy->driver_data;
374 cpufreq_cooling_unregister(priv->cdev);
375 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
376 of_cpumask_free_opp_table(policy->related_cpus);
377 clk_put(policy->clk);
378 if (!IS_ERR(priv->cpu_reg))
379 regulator_put(priv->cpu_reg);
385 static void cpufreq_ready(struct cpufreq_policy *policy)
387 struct private_data *priv = policy->driver_data;
388 struct device_node *np = of_node_get(priv->cpu_dev->of_node);
394 * For now, just loading the cooling device;
395 * thermal DT code takes care of matching them.
397 if (of_find_property(np, "#cooling-cells", NULL)) {
398 priv->cdev = of_cpufreq_cooling_register(np,
399 policy->related_cpus);
400 if (IS_ERR(priv->cdev)) {
401 dev_err(priv->cpu_dev,
402 "running cpufreq without cooling device: %ld\n",
403 PTR_ERR(priv->cdev));
412 static struct cpufreq_driver dt_cpufreq_driver = {
413 .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
414 .verify = cpufreq_generic_frequency_table_verify,
415 .target_index = set_target,
416 .get = cpufreq_generic_get,
417 .init = cpufreq_init,
418 .exit = cpufreq_exit,
419 .ready = cpufreq_ready,
420 .name = "cpufreq-dt",
421 .attr = cpufreq_dt_attr,
424 static int dt_cpufreq_probe(struct platform_device *pdev)
426 struct device *cpu_dev;
427 struct regulator *cpu_reg;
432 * All per-cluster (CPUs sharing clock/voltages) initialization is done
433 * from ->init(). In probe(), we just need to make sure that clk and
434 * regulators are available. Else defer probe and retry.
436 * FIXME: Is checking this only for CPU0 sufficient ?
438 ret = allocate_resources(0, &cpu_dev, &cpu_reg, &cpu_clk);
443 if (!IS_ERR(cpu_reg))
444 regulator_put(cpu_reg);
446 dt_cpufreq_driver.driver_data = dev_get_platdata(&pdev->dev);
448 ret = cpufreq_register_driver(&dt_cpufreq_driver);
450 dev_err(cpu_dev, "failed register driver: %d\n", ret);
455 static int dt_cpufreq_remove(struct platform_device *pdev)
457 cpufreq_unregister_driver(&dt_cpufreq_driver);
461 static struct platform_driver dt_cpufreq_platdrv = {
463 .name = "cpufreq-dt",
465 .probe = dt_cpufreq_probe,
466 .remove = dt_cpufreq_remove,
468 module_platform_driver(dt_cpufreq_platdrv);
470 MODULE_ALIAS("platform:cpufreq-dt");
471 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
472 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
473 MODULE_DESCRIPTION("Generic cpufreq driver");
474 MODULE_LICENSE("GPL");