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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2015 Linaro Ltd.
4 * Author: Pi-Cheng Chen <pi-cheng.chen@linaro.org>
5 */
6
7#include <linux/clk.h>
8#include <linux/cpu.h>
9#include <linux/cpufreq.h>
10#include <linux/cpumask.h>
11#include <linux/minmax.h>
12#include <linux/module.h>
13#include <linux/of.h>
14#include <linux/of_platform.h>
15#include <linux/platform_device.h>
16#include <linux/pm_opp.h>
17#include <linux/regulator/consumer.h>
18
19struct mtk_cpufreq_platform_data {
20 int min_volt_shift;
21 int max_volt_shift;
22 int proc_max_volt;
23 int sram_min_volt;
24 int sram_max_volt;
25 bool ccifreq_supported;
26};
27
28/*
29 * The struct mtk_cpu_dvfs_info holds necessary information for doing CPU DVFS
30 * on each CPU power/clock domain of Mediatek SoCs. Each CPU cluster in
31 * Mediatek SoCs has two voltage inputs, Vproc and Vsram. In some cases the two
32 * voltage inputs need to be controlled under a hardware limitation:
33 * 100mV < Vsram - Vproc < 200mV
34 *
35 * When scaling the clock frequency of a CPU clock domain, the clock source
36 * needs to be switched to another stable PLL clock temporarily until
37 * the original PLL becomes stable at target frequency.
38 */
39struct mtk_cpu_dvfs_info {
40 struct cpumask cpus;
41 struct device *cpu_dev;
42 struct device *cci_dev;
43 struct regulator *proc_reg;
44 struct regulator *sram_reg;
45 struct clk *cpu_clk;
46 struct clk *inter_clk;
47 struct list_head list_head;
48 int intermediate_voltage;
49 bool need_voltage_tracking;
50 int vproc_on_boot;
51 int pre_vproc;
52 /* Avoid race condition for regulators between notify and policy */
53 struct mutex reg_lock;
54 struct notifier_block opp_nb;
55 unsigned int opp_cpu;
56 unsigned long current_freq;
57 const struct mtk_cpufreq_platform_data *soc_data;
58 int vtrack_max;
59 bool ccifreq_bound;
60};
61
62static struct platform_device *cpufreq_pdev;
63
64static LIST_HEAD(dvfs_info_list);
65
66static struct mtk_cpu_dvfs_info *mtk_cpu_dvfs_info_lookup(int cpu)
67{
68 struct mtk_cpu_dvfs_info *info;
69
70 list_for_each_entry(info, &dvfs_info_list, list_head) {
71 if (cpumask_test_cpu(cpu, &info->cpus))
72 return info;
73 }
74
75 return NULL;
76}
77
78static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info,
79 int new_vproc)
80{
81 const struct mtk_cpufreq_platform_data *soc_data = info->soc_data;
82 struct regulator *proc_reg = info->proc_reg;
83 struct regulator *sram_reg = info->sram_reg;
84 int pre_vproc, pre_vsram, new_vsram, vsram, vproc, ret;
85 int retry = info->vtrack_max;
86
87 pre_vproc = regulator_get_voltage(proc_reg);
88 if (pre_vproc < 0) {
89 dev_err(info->cpu_dev,
90 "invalid Vproc value: %d\n", pre_vproc);
91 return pre_vproc;
92 }
93
94 pre_vsram = regulator_get_voltage(sram_reg);
95 if (pre_vsram < 0) {
96 dev_err(info->cpu_dev, "invalid Vsram value: %d\n", pre_vsram);
97 return pre_vsram;
98 }
99
100 new_vsram = clamp(new_vproc + soc_data->min_volt_shift,
101 soc_data->sram_min_volt, soc_data->sram_max_volt);
102
103 do {
104 if (pre_vproc <= new_vproc) {
105 vsram = clamp(pre_vproc + soc_data->max_volt_shift,
106 soc_data->sram_min_volt, new_vsram);
107 ret = regulator_set_voltage(sram_reg, vsram,
108 soc_data->sram_max_volt);
109
110 if (ret)
111 return ret;
112
113 if (vsram == soc_data->sram_max_volt ||
114 new_vsram == soc_data->sram_min_volt)
115 vproc = new_vproc;
116 else
117 vproc = vsram - soc_data->min_volt_shift;
118
119 ret = regulator_set_voltage(proc_reg, vproc,
120 soc_data->proc_max_volt);
121 if (ret) {
122 regulator_set_voltage(sram_reg, pre_vsram,
123 soc_data->sram_max_volt);
124 return ret;
125 }
126 } else if (pre_vproc > new_vproc) {
127 vproc = max(new_vproc,
128 pre_vsram - soc_data->max_volt_shift);
129 ret = regulator_set_voltage(proc_reg, vproc,
130 soc_data->proc_max_volt);
131 if (ret)
132 return ret;
133
134 if (vproc == new_vproc)
135 vsram = new_vsram;
136 else
137 vsram = max(new_vsram,
138 vproc + soc_data->min_volt_shift);
139
140 ret = regulator_set_voltage(sram_reg, vsram,
141 soc_data->sram_max_volt);
142 if (ret) {
143 regulator_set_voltage(proc_reg, pre_vproc,
144 soc_data->proc_max_volt);
145 return ret;
146 }
147 }
148
149 pre_vproc = vproc;
150 pre_vsram = vsram;
151
152 if (--retry < 0) {
153 dev_err(info->cpu_dev,
154 "over loop count, failed to set voltage\n");
155 return -EINVAL;
156 }
157 } while (vproc != new_vproc || vsram != new_vsram);
158
159 return 0;
160}
161
162static int mtk_cpufreq_set_voltage(struct mtk_cpu_dvfs_info *info, int vproc)
163{
164 const struct mtk_cpufreq_platform_data *soc_data = info->soc_data;
165 int ret;
166
167 if (info->need_voltage_tracking)
168 ret = mtk_cpufreq_voltage_tracking(info, vproc);
169 else
170 ret = regulator_set_voltage(info->proc_reg, vproc,
171 soc_data->proc_max_volt);
172 if (!ret)
173 info->pre_vproc = vproc;
174
175 return ret;
176}
177
178static bool is_ccifreq_ready(struct mtk_cpu_dvfs_info *info)
179{
180 struct device_link *sup_link;
181
182 if (info->ccifreq_bound)
183 return true;
184
185 sup_link = device_link_add(info->cpu_dev, info->cci_dev,
186 DL_FLAG_AUTOREMOVE_CONSUMER);
187 if (!sup_link) {
188 dev_err(info->cpu_dev, "cpu%d: sup_link is NULL\n", info->opp_cpu);
189 return false;
190 }
191
192 if (sup_link->supplier->links.status != DL_DEV_DRIVER_BOUND)
193 return false;
194
195 info->ccifreq_bound = true;
196
197 return true;
198}
199
200static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
201 unsigned int index)
202{
203 struct cpufreq_frequency_table *freq_table = policy->freq_table;
204 struct clk *cpu_clk = policy->clk;
205 struct clk *armpll = clk_get_parent(cpu_clk);
206 struct mtk_cpu_dvfs_info *info = policy->driver_data;
207 struct device *cpu_dev = info->cpu_dev;
208 struct dev_pm_opp *opp;
209 long freq_hz, pre_freq_hz;
210 int vproc, pre_vproc, inter_vproc, target_vproc, ret;
211
212 inter_vproc = info->intermediate_voltage;
213
214 pre_freq_hz = clk_get_rate(cpu_clk);
215
216 mutex_lock(&info->reg_lock);
217
218 if (unlikely(info->pre_vproc <= 0))
219 pre_vproc = regulator_get_voltage(info->proc_reg);
220 else
221 pre_vproc = info->pre_vproc;
222
223 if (pre_vproc < 0) {
224 dev_err(cpu_dev, "invalid Vproc value: %d\n", pre_vproc);
225 ret = pre_vproc;
226 goto out;
227 }
228
229 freq_hz = freq_table[index].frequency * 1000;
230
231 opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_hz);
232 if (IS_ERR(opp)) {
233 dev_err(cpu_dev, "cpu%d: failed to find OPP for %ld\n",
234 policy->cpu, freq_hz);
235 ret = PTR_ERR(opp);
236 goto out;
237 }
238 vproc = dev_pm_opp_get_voltage(opp);
239 dev_pm_opp_put(opp);
240
241 /*
242 * If MediaTek cci is supported but is not ready, we will use the value
243 * of max(target cpu voltage, booting voltage) to prevent high freqeuncy
244 * low voltage crash.
245 */
246 if (info->soc_data->ccifreq_supported && !is_ccifreq_ready(info))
247 vproc = max(vproc, info->vproc_on_boot);
248
249 /*
250 * If the new voltage or the intermediate voltage is higher than the
251 * current voltage, scale up voltage first.
252 */
253 target_vproc = max(inter_vproc, vproc);
254 if (pre_vproc <= target_vproc) {
255 ret = mtk_cpufreq_set_voltage(info, target_vproc);
256 if (ret) {
257 dev_err(cpu_dev,
258 "cpu%d: failed to scale up voltage!\n", policy->cpu);
259 mtk_cpufreq_set_voltage(info, pre_vproc);
260 goto out;
261 }
262 }
263
264 /* Reparent the CPU clock to intermediate clock. */
265 ret = clk_set_parent(cpu_clk, info->inter_clk);
266 if (ret) {
267 dev_err(cpu_dev,
268 "cpu%d: failed to re-parent cpu clock!\n", policy->cpu);
269 mtk_cpufreq_set_voltage(info, pre_vproc);
270 goto out;
271 }
272
273 /* Set the original PLL to target rate. */
274 ret = clk_set_rate(armpll, freq_hz);
275 if (ret) {
276 dev_err(cpu_dev,
277 "cpu%d: failed to scale cpu clock rate!\n", policy->cpu);
278 clk_set_parent(cpu_clk, armpll);
279 mtk_cpufreq_set_voltage(info, pre_vproc);
280 goto out;
281 }
282
283 /* Set parent of CPU clock back to the original PLL. */
284 ret = clk_set_parent(cpu_clk, armpll);
285 if (ret) {
286 dev_err(cpu_dev,
287 "cpu%d: failed to re-parent cpu clock!\n", policy->cpu);
288 mtk_cpufreq_set_voltage(info, inter_vproc);
289 goto out;
290 }
291
292 /*
293 * If the new voltage is lower than the intermediate voltage or the
294 * original voltage, scale down to the new voltage.
295 */
296 if (vproc < inter_vproc || vproc < pre_vproc) {
297 ret = mtk_cpufreq_set_voltage(info, vproc);
298 if (ret) {
299 dev_err(cpu_dev,
300 "cpu%d: failed to scale down voltage!\n", policy->cpu);
301 clk_set_parent(cpu_clk, info->inter_clk);
302 clk_set_rate(armpll, pre_freq_hz);
303 clk_set_parent(cpu_clk, armpll);
304 goto out;
305 }
306 }
307
308 info->current_freq = freq_hz;
309
310out:
311 mutex_unlock(&info->reg_lock);
312
313 return ret;
314}
315
316static int mtk_cpufreq_opp_notifier(struct notifier_block *nb,
317 unsigned long event, void *data)
318{
319 struct dev_pm_opp *opp = data;
320 struct dev_pm_opp *new_opp;
321 struct mtk_cpu_dvfs_info *info;
322 unsigned long freq, volt;
323 struct cpufreq_policy *policy;
324 int ret = 0;
325
326 info = container_of(nb, struct mtk_cpu_dvfs_info, opp_nb);
327
328 if (event == OPP_EVENT_ADJUST_VOLTAGE) {
329 freq = dev_pm_opp_get_freq(opp);
330
331 mutex_lock(&info->reg_lock);
332 if (info->current_freq == freq) {
333 volt = dev_pm_opp_get_voltage(opp);
334 ret = mtk_cpufreq_set_voltage(info, volt);
335 if (ret)
336 dev_err(info->cpu_dev,
337 "failed to scale voltage: %d\n", ret);
338 }
339 mutex_unlock(&info->reg_lock);
340 } else if (event == OPP_EVENT_DISABLE) {
341 freq = dev_pm_opp_get_freq(opp);
342
343 /* case of current opp item is disabled */
344 if (info->current_freq == freq) {
345 freq = 1;
346 new_opp = dev_pm_opp_find_freq_ceil(info->cpu_dev,
347 &freq);
348 if (IS_ERR(new_opp)) {
349 dev_err(info->cpu_dev,
350 "all opp items are disabled\n");
351 ret = PTR_ERR(new_opp);
352 return notifier_from_errno(ret);
353 }
354
355 dev_pm_opp_put(new_opp);
356 policy = cpufreq_cpu_get(info->opp_cpu);
357 if (policy) {
358 cpufreq_driver_target(policy, freq / 1000,
359 CPUFREQ_RELATION_L);
360 cpufreq_cpu_put(policy);
361 }
362 }
363 }
364
365 return notifier_from_errno(ret);
366}
367
368static struct device *of_get_cci(struct device *cpu_dev)
369{
370 struct device_node *np;
371 struct platform_device *pdev;
372
373 np = of_parse_phandle(cpu_dev->of_node, "mediatek,cci", 0);
374 if (!np)
375 return ERR_PTR(-ENODEV);
376
377 pdev = of_find_device_by_node(np);
378 of_node_put(np);
379 if (!pdev)
380 return ERR_PTR(-ENODEV);
381
382 return &pdev->dev;
383}
384
385static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
386{
387 struct device *cpu_dev;
388 struct dev_pm_opp *opp;
389 unsigned long rate;
390 int ret;
391
392 cpu_dev = get_cpu_device(cpu);
393 if (!cpu_dev) {
394 dev_err(cpu_dev, "failed to get cpu%d device\n", cpu);
395 return -ENODEV;
396 }
397 info->cpu_dev = cpu_dev;
398
399 info->ccifreq_bound = false;
400 if (info->soc_data->ccifreq_supported) {
401 info->cci_dev = of_get_cci(info->cpu_dev);
402 if (IS_ERR(info->cci_dev)) {
403 ret = PTR_ERR(info->cci_dev);
404 dev_err(cpu_dev, "cpu%d: failed to get cci device\n", cpu);
405 return -ENODEV;
406 }
407 }
408
409 info->cpu_clk = clk_get(cpu_dev, "cpu");
410 if (IS_ERR(info->cpu_clk)) {
411 ret = PTR_ERR(info->cpu_clk);
412 return dev_err_probe(cpu_dev, ret,
413 "cpu%d: failed to get cpu clk\n", cpu);
414 }
415
416 info->inter_clk = clk_get(cpu_dev, "intermediate");
417 if (IS_ERR(info->inter_clk)) {
418 ret = PTR_ERR(info->inter_clk);
419 dev_err_probe(cpu_dev, ret,
420 "cpu%d: failed to get intermediate clk\n", cpu);
421 goto out_free_mux_clock;
422 }
423
424 info->proc_reg = regulator_get_optional(cpu_dev, "proc");
425 if (IS_ERR(info->proc_reg)) {
426 ret = PTR_ERR(info->proc_reg);
427 dev_err_probe(cpu_dev, ret,
428 "cpu%d: failed to get proc regulator\n", cpu);
429 goto out_free_inter_clock;
430 }
431
432 ret = regulator_enable(info->proc_reg);
433 if (ret) {
434 dev_warn(cpu_dev, "cpu%d: failed to enable vproc\n", cpu);
435 goto out_free_proc_reg;
436 }
437
438 /* Both presence and absence of sram regulator are valid cases. */
439 info->sram_reg = regulator_get_optional(cpu_dev, "sram");
440 if (IS_ERR(info->sram_reg)) {
441 ret = PTR_ERR(info->sram_reg);
442 if (ret == -EPROBE_DEFER)
443 goto out_disable_proc_reg;
444
445 info->sram_reg = NULL;
446 } else {
447 ret = regulator_enable(info->sram_reg);
448 if (ret) {
449 dev_warn(cpu_dev, "cpu%d: failed to enable vsram\n", cpu);
450 goto out_free_sram_reg;
451 }
452 }
453
454 /* Get OPP-sharing information from "operating-points-v2" bindings */
455 ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, &info->cpus);
456 if (ret) {
457 dev_err(cpu_dev,
458 "cpu%d: failed to get OPP-sharing information\n", cpu);
459 goto out_disable_sram_reg;
460 }
461
462 ret = dev_pm_opp_of_cpumask_add_table(&info->cpus);
463 if (ret) {
464 dev_warn(cpu_dev, "cpu%d: no OPP table\n", cpu);
465 goto out_disable_sram_reg;
466 }
467
468 ret = clk_prepare_enable(info->cpu_clk);
469 if (ret)
470 goto out_free_opp_table;
471
472 ret = clk_prepare_enable(info->inter_clk);
473 if (ret)
474 goto out_disable_mux_clock;
475
476 if (info->soc_data->ccifreq_supported) {
477 info->vproc_on_boot = regulator_get_voltage(info->proc_reg);
478 if (info->vproc_on_boot < 0) {
479 ret = info->vproc_on_boot;
480 dev_err(info->cpu_dev,
481 "invalid Vproc value: %d\n", info->vproc_on_boot);
482 goto out_disable_inter_clock;
483 }
484 }
485
486 /* Search a safe voltage for intermediate frequency. */
487 rate = clk_get_rate(info->inter_clk);
488 opp = dev_pm_opp_find_freq_ceil(cpu_dev, &rate);
489 if (IS_ERR(opp)) {
490 dev_err(cpu_dev, "cpu%d: failed to get intermediate opp\n", cpu);
491 ret = PTR_ERR(opp);
492 goto out_disable_inter_clock;
493 }
494 info->intermediate_voltage = dev_pm_opp_get_voltage(opp);
495 dev_pm_opp_put(opp);
496
497 mutex_init(&info->reg_lock);
498 info->current_freq = clk_get_rate(info->cpu_clk);
499
500 info->opp_cpu = cpu;
501 info->opp_nb.notifier_call = mtk_cpufreq_opp_notifier;
502 ret = dev_pm_opp_register_notifier(cpu_dev, &info->opp_nb);
503 if (ret) {
504 dev_err(cpu_dev, "cpu%d: failed to register opp notifier\n", cpu);
505 goto out_disable_inter_clock;
506 }
507
508 /*
509 * If SRAM regulator is present, software "voltage tracking" is needed
510 * for this CPU power domain.
511 */
512 info->need_voltage_tracking = (info->sram_reg != NULL);
513
514 /*
515 * We assume min voltage is 0 and tracking target voltage using
516 * min_volt_shift for each iteration.
517 * The vtrack_max is 3 times of expeted iteration count.
518 */
519 info->vtrack_max = 3 * DIV_ROUND_UP(max(info->soc_data->sram_max_volt,
520 info->soc_data->proc_max_volt),
521 info->soc_data->min_volt_shift);
522
523 return 0;
524
525out_disable_inter_clock:
526 clk_disable_unprepare(info->inter_clk);
527
528out_disable_mux_clock:
529 clk_disable_unprepare(info->cpu_clk);
530
531out_free_opp_table:
532 dev_pm_opp_of_cpumask_remove_table(&info->cpus);
533
534out_disable_sram_reg:
535 if (info->sram_reg)
536 regulator_disable(info->sram_reg);
537
538out_free_sram_reg:
539 if (info->sram_reg)
540 regulator_put(info->sram_reg);
541
542out_disable_proc_reg:
543 regulator_disable(info->proc_reg);
544
545out_free_proc_reg:
546 regulator_put(info->proc_reg);
547
548out_free_inter_clock:
549 clk_put(info->inter_clk);
550
551out_free_mux_clock:
552 clk_put(info->cpu_clk);
553
554 return ret;
555}
556
557static void mtk_cpu_dvfs_info_release(struct mtk_cpu_dvfs_info *info)
558{
559 regulator_disable(info->proc_reg);
560 regulator_put(info->proc_reg);
561 if (info->sram_reg) {
562 regulator_disable(info->sram_reg);
563 regulator_put(info->sram_reg);
564 }
565 clk_disable_unprepare(info->cpu_clk);
566 clk_put(info->cpu_clk);
567 clk_disable_unprepare(info->inter_clk);
568 clk_put(info->inter_clk);
569 dev_pm_opp_of_cpumask_remove_table(&info->cpus);
570 dev_pm_opp_unregister_notifier(info->cpu_dev, &info->opp_nb);
571}
572
573static int mtk_cpufreq_init(struct cpufreq_policy *policy)
574{
575 struct mtk_cpu_dvfs_info *info;
576 struct cpufreq_frequency_table *freq_table;
577 int ret;
578
579 info = mtk_cpu_dvfs_info_lookup(policy->cpu);
580 if (!info) {
581 pr_err("dvfs info for cpu%d is not initialized.\n",
582 policy->cpu);
583 return -EINVAL;
584 }
585
586 ret = dev_pm_opp_init_cpufreq_table(info->cpu_dev, &freq_table);
587 if (ret) {
588 dev_err(info->cpu_dev,
589 "failed to init cpufreq table for cpu%d: %d\n",
590 policy->cpu, ret);
591 return ret;
592 }
593
594 cpumask_copy(policy->cpus, &info->cpus);
595 policy->freq_table = freq_table;
596 policy->driver_data = info;
597 policy->clk = info->cpu_clk;
598
599 return 0;
600}
601
602static int mtk_cpufreq_exit(struct cpufreq_policy *policy)
603{
604 struct mtk_cpu_dvfs_info *info = policy->driver_data;
605
606 dev_pm_opp_free_cpufreq_table(info->cpu_dev, &policy->freq_table);
607
608 return 0;
609}
610
611static struct cpufreq_driver mtk_cpufreq_driver = {
612 .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK |
613 CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
614 CPUFREQ_IS_COOLING_DEV,
615 .verify = cpufreq_generic_frequency_table_verify,
616 .target_index = mtk_cpufreq_set_target,
617 .get = cpufreq_generic_get,
618 .init = mtk_cpufreq_init,
619 .exit = mtk_cpufreq_exit,
620 .register_em = cpufreq_register_em_with_opp,
621 .name = "mtk-cpufreq",
622 .attr = cpufreq_generic_attr,
623};
624
625static int mtk_cpufreq_probe(struct platform_device *pdev)
626{
627 const struct mtk_cpufreq_platform_data *data;
628 struct mtk_cpu_dvfs_info *info, *tmp;
629 int cpu, ret;
630
631 data = dev_get_platdata(&pdev->dev);
632 if (!data) {
633 dev_err(&pdev->dev,
634 "failed to get mtk cpufreq platform data\n");
635 return -ENODEV;
636 }
637
638 for_each_possible_cpu(cpu) {
639 info = mtk_cpu_dvfs_info_lookup(cpu);
640 if (info)
641 continue;
642
643 info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
644 if (!info) {
645 ret = -ENOMEM;
646 goto release_dvfs_info_list;
647 }
648
649 info->soc_data = data;
650 ret = mtk_cpu_dvfs_info_init(info, cpu);
651 if (ret) {
652 dev_err(&pdev->dev,
653 "failed to initialize dvfs info for cpu%d\n",
654 cpu);
655 goto release_dvfs_info_list;
656 }
657
658 list_add(&info->list_head, &dvfs_info_list);
659 }
660
661 ret = cpufreq_register_driver(&mtk_cpufreq_driver);
662 if (ret) {
663 dev_err(&pdev->dev, "failed to register mtk cpufreq driver\n");
664 goto release_dvfs_info_list;
665 }
666
667 return 0;
668
669release_dvfs_info_list:
670 list_for_each_entry_safe(info, tmp, &dvfs_info_list, list_head) {
671 mtk_cpu_dvfs_info_release(info);
672 list_del(&info->list_head);
673 }
674
675 return ret;
676}
677
678static struct platform_driver mtk_cpufreq_platdrv = {
679 .driver = {
680 .name = "mtk-cpufreq",
681 },
682 .probe = mtk_cpufreq_probe,
683};
684
685static const struct mtk_cpufreq_platform_data mt2701_platform_data = {
686 .min_volt_shift = 100000,
687 .max_volt_shift = 200000,
688 .proc_max_volt = 1150000,
689 .sram_min_volt = 0,
690 .sram_max_volt = 1150000,
691 .ccifreq_supported = false,
692};
693
694static const struct mtk_cpufreq_platform_data mt7622_platform_data = {
695 .min_volt_shift = 100000,
696 .max_volt_shift = 200000,
697 .proc_max_volt = 1350000,
698 .sram_min_volt = 0,
699 .sram_max_volt = 1350000,
700 .ccifreq_supported = false,
701};
702
703static const struct mtk_cpufreq_platform_data mt7623_platform_data = {
704 .min_volt_shift = 100000,
705 .max_volt_shift = 200000,
706 .proc_max_volt = 1300000,
707 .ccifreq_supported = false,
708};
709
710static const struct mtk_cpufreq_platform_data mt8183_platform_data = {
711 .min_volt_shift = 100000,
712 .max_volt_shift = 200000,
713 .proc_max_volt = 1150000,
714 .sram_min_volt = 0,
715 .sram_max_volt = 1150000,
716 .ccifreq_supported = true,
717};
718
719static const struct mtk_cpufreq_platform_data mt8186_platform_data = {
720 .min_volt_shift = 100000,
721 .max_volt_shift = 250000,
722 .proc_max_volt = 1118750,
723 .sram_min_volt = 850000,
724 .sram_max_volt = 1118750,
725 .ccifreq_supported = true,
726};
727
728static const struct mtk_cpufreq_platform_data mt8516_platform_data = {
729 .min_volt_shift = 100000,
730 .max_volt_shift = 200000,
731 .proc_max_volt = 1310000,
732 .sram_min_volt = 0,
733 .sram_max_volt = 1310000,
734 .ccifreq_supported = false,
735};
736
737/* List of machines supported by this driver */
738static const struct of_device_id mtk_cpufreq_machines[] __initconst = {
739 { .compatible = "mediatek,mt2701", .data = &mt2701_platform_data },
740 { .compatible = "mediatek,mt2712", .data = &mt2701_platform_data },
741 { .compatible = "mediatek,mt7622", .data = &mt7622_platform_data },
742 { .compatible = "mediatek,mt7623", .data = &mt7623_platform_data },
743 { .compatible = "mediatek,mt8167", .data = &mt8516_platform_data },
744 { .compatible = "mediatek,mt817x", .data = &mt2701_platform_data },
745 { .compatible = "mediatek,mt8173", .data = &mt2701_platform_data },
746 { .compatible = "mediatek,mt8176", .data = &mt2701_platform_data },
747 { .compatible = "mediatek,mt8183", .data = &mt8183_platform_data },
748 { .compatible = "mediatek,mt8186", .data = &mt8186_platform_data },
749 { .compatible = "mediatek,mt8365", .data = &mt2701_platform_data },
750 { .compatible = "mediatek,mt8516", .data = &mt8516_platform_data },
751 { }
752};
753MODULE_DEVICE_TABLE(of, mtk_cpufreq_machines);
754
755static int __init mtk_cpufreq_driver_init(void)
756{
757 struct device_node *np;
758 const struct of_device_id *match;
759 const struct mtk_cpufreq_platform_data *data;
760 int err;
761
762 np = of_find_node_by_path("/");
763 if (!np)
764 return -ENODEV;
765
766 match = of_match_node(mtk_cpufreq_machines, np);
767 of_node_put(np);
768 if (!match) {
769 pr_debug("Machine is not compatible with mtk-cpufreq\n");
770 return -ENODEV;
771 }
772 data = match->data;
773
774 err = platform_driver_register(&mtk_cpufreq_platdrv);
775 if (err)
776 return err;
777
778 /*
779 * Since there's no place to hold device registration code and no
780 * device tree based way to match cpufreq driver yet, both the driver
781 * and the device registration codes are put here to handle defer
782 * probing.
783 */
784 cpufreq_pdev = platform_device_register_data(NULL, "mtk-cpufreq", -1,
785 data, sizeof(*data));
786 if (IS_ERR(cpufreq_pdev)) {
787 pr_err("failed to register mtk-cpufreq platform device\n");
788 platform_driver_unregister(&mtk_cpufreq_platdrv);
789 return PTR_ERR(cpufreq_pdev);
790 }
791
792 return 0;
793}
794module_init(mtk_cpufreq_driver_init)
795
796static void __exit mtk_cpufreq_driver_exit(void)
797{
798 platform_device_unregister(cpufreq_pdev);
799 platform_driver_unregister(&mtk_cpufreq_platdrv);
800}
801module_exit(mtk_cpufreq_driver_exit)
802
803MODULE_DESCRIPTION("MediaTek CPUFreq driver");
804MODULE_AUTHOR("Pi-Cheng Chen <pi-cheng.chen@linaro.org>");
805MODULE_LICENSE("GPL v2");
1/*
2 * Copyright (c) 2015 Linaro Ltd.
3 * Author: Pi-Cheng Chen <pi-cheng.chen@linaro.org>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 */
14
15#include <linux/clk.h>
16#include <linux/cpu.h>
17#include <linux/cpu_cooling.h>
18#include <linux/cpufreq.h>
19#include <linux/cpumask.h>
20#include <linux/module.h>
21#include <linux/of.h>
22#include <linux/platform_device.h>
23#include <linux/pm_opp.h>
24#include <linux/regulator/consumer.h>
25#include <linux/slab.h>
26#include <linux/thermal.h>
27
28#define MIN_VOLT_SHIFT (100000)
29#define MAX_VOLT_SHIFT (200000)
30#define MAX_VOLT_LIMIT (1150000)
31#define VOLT_TOL (10000)
32
33/*
34 * The struct mtk_cpu_dvfs_info holds necessary information for doing CPU DVFS
35 * on each CPU power/clock domain of Mediatek SoCs. Each CPU cluster in
36 * Mediatek SoCs has two voltage inputs, Vproc and Vsram. In some cases the two
37 * voltage inputs need to be controlled under a hardware limitation:
38 * 100mV < Vsram - Vproc < 200mV
39 *
40 * When scaling the clock frequency of a CPU clock domain, the clock source
41 * needs to be switched to another stable PLL clock temporarily until
42 * the original PLL becomes stable at target frequency.
43 */
44struct mtk_cpu_dvfs_info {
45 struct cpumask cpus;
46 struct device *cpu_dev;
47 struct regulator *proc_reg;
48 struct regulator *sram_reg;
49 struct clk *cpu_clk;
50 struct clk *inter_clk;
51 struct thermal_cooling_device *cdev;
52 struct list_head list_head;
53 int intermediate_voltage;
54 bool need_voltage_tracking;
55};
56
57static LIST_HEAD(dvfs_info_list);
58
59static struct mtk_cpu_dvfs_info *mtk_cpu_dvfs_info_lookup(int cpu)
60{
61 struct mtk_cpu_dvfs_info *info;
62
63 list_for_each_entry(info, &dvfs_info_list, list_head) {
64 if (cpumask_test_cpu(cpu, &info->cpus))
65 return info;
66 }
67
68 return NULL;
69}
70
71static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info,
72 int new_vproc)
73{
74 struct regulator *proc_reg = info->proc_reg;
75 struct regulator *sram_reg = info->sram_reg;
76 int old_vproc, old_vsram, new_vsram, vsram, vproc, ret;
77
78 old_vproc = regulator_get_voltage(proc_reg);
79 if (old_vproc < 0) {
80 pr_err("%s: invalid Vproc value: %d\n", __func__, old_vproc);
81 return old_vproc;
82 }
83 /* Vsram should not exceed the maximum allowed voltage of SoC. */
84 new_vsram = min(new_vproc + MIN_VOLT_SHIFT, MAX_VOLT_LIMIT);
85
86 if (old_vproc < new_vproc) {
87 /*
88 * When scaling up voltages, Vsram and Vproc scale up step
89 * by step. At each step, set Vsram to (Vproc + 200mV) first,
90 * then set Vproc to (Vsram - 100mV).
91 * Keep doing it until Vsram and Vproc hit target voltages.
92 */
93 do {
94 old_vsram = regulator_get_voltage(sram_reg);
95 if (old_vsram < 0) {
96 pr_err("%s: invalid Vsram value: %d\n",
97 __func__, old_vsram);
98 return old_vsram;
99 }
100 old_vproc = regulator_get_voltage(proc_reg);
101 if (old_vproc < 0) {
102 pr_err("%s: invalid Vproc value: %d\n",
103 __func__, old_vproc);
104 return old_vproc;
105 }
106
107 vsram = min(new_vsram, old_vproc + MAX_VOLT_SHIFT);
108
109 if (vsram + VOLT_TOL >= MAX_VOLT_LIMIT) {
110 vsram = MAX_VOLT_LIMIT;
111
112 /*
113 * If the target Vsram hits the maximum voltage,
114 * try to set the exact voltage value first.
115 */
116 ret = regulator_set_voltage(sram_reg, vsram,
117 vsram);
118 if (ret)
119 ret = regulator_set_voltage(sram_reg,
120 vsram - VOLT_TOL,
121 vsram);
122
123 vproc = new_vproc;
124 } else {
125 ret = regulator_set_voltage(sram_reg, vsram,
126 vsram + VOLT_TOL);
127
128 vproc = vsram - MIN_VOLT_SHIFT;
129 }
130 if (ret)
131 return ret;
132
133 ret = regulator_set_voltage(proc_reg, vproc,
134 vproc + VOLT_TOL);
135 if (ret) {
136 regulator_set_voltage(sram_reg, old_vsram,
137 old_vsram);
138 return ret;
139 }
140 } while (vproc < new_vproc || vsram < new_vsram);
141 } else if (old_vproc > new_vproc) {
142 /*
143 * When scaling down voltages, Vsram and Vproc scale down step
144 * by step. At each step, set Vproc to (Vsram - 200mV) first,
145 * then set Vproc to (Vproc + 100mV).
146 * Keep doing it until Vsram and Vproc hit target voltages.
147 */
148 do {
149 old_vproc = regulator_get_voltage(proc_reg);
150 if (old_vproc < 0) {
151 pr_err("%s: invalid Vproc value: %d\n",
152 __func__, old_vproc);
153 return old_vproc;
154 }
155 old_vsram = regulator_get_voltage(sram_reg);
156 if (old_vsram < 0) {
157 pr_err("%s: invalid Vsram value: %d\n",
158 __func__, old_vsram);
159 return old_vsram;
160 }
161
162 vproc = max(new_vproc, old_vsram - MAX_VOLT_SHIFT);
163 ret = regulator_set_voltage(proc_reg, vproc,
164 vproc + VOLT_TOL);
165 if (ret)
166 return ret;
167
168 if (vproc == new_vproc)
169 vsram = new_vsram;
170 else
171 vsram = max(new_vsram, vproc + MIN_VOLT_SHIFT);
172
173 if (vsram + VOLT_TOL >= MAX_VOLT_LIMIT) {
174 vsram = MAX_VOLT_LIMIT;
175
176 /*
177 * If the target Vsram hits the maximum voltage,
178 * try to set the exact voltage value first.
179 */
180 ret = regulator_set_voltage(sram_reg, vsram,
181 vsram);
182 if (ret)
183 ret = regulator_set_voltage(sram_reg,
184 vsram - VOLT_TOL,
185 vsram);
186 } else {
187 ret = regulator_set_voltage(sram_reg, vsram,
188 vsram + VOLT_TOL);
189 }
190
191 if (ret) {
192 regulator_set_voltage(proc_reg, old_vproc,
193 old_vproc);
194 return ret;
195 }
196 } while (vproc > new_vproc + VOLT_TOL ||
197 vsram > new_vsram + VOLT_TOL);
198 }
199
200 return 0;
201}
202
203static int mtk_cpufreq_set_voltage(struct mtk_cpu_dvfs_info *info, int vproc)
204{
205 if (info->need_voltage_tracking)
206 return mtk_cpufreq_voltage_tracking(info, vproc);
207 else
208 return regulator_set_voltage(info->proc_reg, vproc,
209 vproc + VOLT_TOL);
210}
211
212static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
213 unsigned int index)
214{
215 struct cpufreq_frequency_table *freq_table = policy->freq_table;
216 struct clk *cpu_clk = policy->clk;
217 struct clk *armpll = clk_get_parent(cpu_clk);
218 struct mtk_cpu_dvfs_info *info = policy->driver_data;
219 struct device *cpu_dev = info->cpu_dev;
220 struct dev_pm_opp *opp;
221 long freq_hz, old_freq_hz;
222 int vproc, old_vproc, inter_vproc, target_vproc, ret;
223
224 inter_vproc = info->intermediate_voltage;
225
226 old_freq_hz = clk_get_rate(cpu_clk);
227 old_vproc = regulator_get_voltage(info->proc_reg);
228 if (old_vproc < 0) {
229 pr_err("%s: invalid Vproc value: %d\n", __func__, old_vproc);
230 return old_vproc;
231 }
232
233 freq_hz = freq_table[index].frequency * 1000;
234
235 opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_hz);
236 if (IS_ERR(opp)) {
237 pr_err("cpu%d: failed to find OPP for %ld\n",
238 policy->cpu, freq_hz);
239 return PTR_ERR(opp);
240 }
241 vproc = dev_pm_opp_get_voltage(opp);
242 dev_pm_opp_put(opp);
243
244 /*
245 * If the new voltage or the intermediate voltage is higher than the
246 * current voltage, scale up voltage first.
247 */
248 target_vproc = (inter_vproc > vproc) ? inter_vproc : vproc;
249 if (old_vproc < target_vproc) {
250 ret = mtk_cpufreq_set_voltage(info, target_vproc);
251 if (ret) {
252 pr_err("cpu%d: failed to scale up voltage!\n",
253 policy->cpu);
254 mtk_cpufreq_set_voltage(info, old_vproc);
255 return ret;
256 }
257 }
258
259 /* Reparent the CPU clock to intermediate clock. */
260 ret = clk_set_parent(cpu_clk, info->inter_clk);
261 if (ret) {
262 pr_err("cpu%d: failed to re-parent cpu clock!\n",
263 policy->cpu);
264 mtk_cpufreq_set_voltage(info, old_vproc);
265 WARN_ON(1);
266 return ret;
267 }
268
269 /* Set the original PLL to target rate. */
270 ret = clk_set_rate(armpll, freq_hz);
271 if (ret) {
272 pr_err("cpu%d: failed to scale cpu clock rate!\n",
273 policy->cpu);
274 clk_set_parent(cpu_clk, armpll);
275 mtk_cpufreq_set_voltage(info, old_vproc);
276 return ret;
277 }
278
279 /* Set parent of CPU clock back to the original PLL. */
280 ret = clk_set_parent(cpu_clk, armpll);
281 if (ret) {
282 pr_err("cpu%d: failed to re-parent cpu clock!\n",
283 policy->cpu);
284 mtk_cpufreq_set_voltage(info, inter_vproc);
285 WARN_ON(1);
286 return ret;
287 }
288
289 /*
290 * If the new voltage is lower than the intermediate voltage or the
291 * original voltage, scale down to the new voltage.
292 */
293 if (vproc < inter_vproc || vproc < old_vproc) {
294 ret = mtk_cpufreq_set_voltage(info, vproc);
295 if (ret) {
296 pr_err("cpu%d: failed to scale down voltage!\n",
297 policy->cpu);
298 clk_set_parent(cpu_clk, info->inter_clk);
299 clk_set_rate(armpll, old_freq_hz);
300 clk_set_parent(cpu_clk, armpll);
301 return ret;
302 }
303 }
304
305 return 0;
306}
307
308#define DYNAMIC_POWER "dynamic-power-coefficient"
309
310static void mtk_cpufreq_ready(struct cpufreq_policy *policy)
311{
312 struct mtk_cpu_dvfs_info *info = policy->driver_data;
313
314 info->cdev = of_cpufreq_cooling_register(policy);
315}
316
317static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
318{
319 struct device *cpu_dev;
320 struct regulator *proc_reg = ERR_PTR(-ENODEV);
321 struct regulator *sram_reg = ERR_PTR(-ENODEV);
322 struct clk *cpu_clk = ERR_PTR(-ENODEV);
323 struct clk *inter_clk = ERR_PTR(-ENODEV);
324 struct dev_pm_opp *opp;
325 unsigned long rate;
326 int ret;
327
328 cpu_dev = get_cpu_device(cpu);
329 if (!cpu_dev) {
330 pr_err("failed to get cpu%d device\n", cpu);
331 return -ENODEV;
332 }
333
334 cpu_clk = clk_get(cpu_dev, "cpu");
335 if (IS_ERR(cpu_clk)) {
336 if (PTR_ERR(cpu_clk) == -EPROBE_DEFER)
337 pr_warn("cpu clk for cpu%d not ready, retry.\n", cpu);
338 else
339 pr_err("failed to get cpu clk for cpu%d\n", cpu);
340
341 ret = PTR_ERR(cpu_clk);
342 return ret;
343 }
344
345 inter_clk = clk_get(cpu_dev, "intermediate");
346 if (IS_ERR(inter_clk)) {
347 if (PTR_ERR(inter_clk) == -EPROBE_DEFER)
348 pr_warn("intermediate clk for cpu%d not ready, retry.\n",
349 cpu);
350 else
351 pr_err("failed to get intermediate clk for cpu%d\n",
352 cpu);
353
354 ret = PTR_ERR(inter_clk);
355 goto out_free_resources;
356 }
357
358 proc_reg = regulator_get_exclusive(cpu_dev, "proc");
359 if (IS_ERR(proc_reg)) {
360 if (PTR_ERR(proc_reg) == -EPROBE_DEFER)
361 pr_warn("proc regulator for cpu%d not ready, retry.\n",
362 cpu);
363 else
364 pr_err("failed to get proc regulator for cpu%d\n",
365 cpu);
366
367 ret = PTR_ERR(proc_reg);
368 goto out_free_resources;
369 }
370
371 /* Both presence and absence of sram regulator are valid cases. */
372 sram_reg = regulator_get_exclusive(cpu_dev, "sram");
373
374 /* Get OPP-sharing information from "operating-points-v2" bindings */
375 ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, &info->cpus);
376 if (ret) {
377 pr_err("failed to get OPP-sharing information for cpu%d\n",
378 cpu);
379 goto out_free_resources;
380 }
381
382 ret = dev_pm_opp_of_cpumask_add_table(&info->cpus);
383 if (ret) {
384 pr_warn("no OPP table for cpu%d\n", cpu);
385 goto out_free_resources;
386 }
387
388 /* Search a safe voltage for intermediate frequency. */
389 rate = clk_get_rate(inter_clk);
390 opp = dev_pm_opp_find_freq_ceil(cpu_dev, &rate);
391 if (IS_ERR(opp)) {
392 pr_err("failed to get intermediate opp for cpu%d\n", cpu);
393 ret = PTR_ERR(opp);
394 goto out_free_opp_table;
395 }
396 info->intermediate_voltage = dev_pm_opp_get_voltage(opp);
397 dev_pm_opp_put(opp);
398
399 info->cpu_dev = cpu_dev;
400 info->proc_reg = proc_reg;
401 info->sram_reg = IS_ERR(sram_reg) ? NULL : sram_reg;
402 info->cpu_clk = cpu_clk;
403 info->inter_clk = inter_clk;
404
405 /*
406 * If SRAM regulator is present, software "voltage tracking" is needed
407 * for this CPU power domain.
408 */
409 info->need_voltage_tracking = !IS_ERR(sram_reg);
410
411 return 0;
412
413out_free_opp_table:
414 dev_pm_opp_of_cpumask_remove_table(&info->cpus);
415
416out_free_resources:
417 if (!IS_ERR(proc_reg))
418 regulator_put(proc_reg);
419 if (!IS_ERR(sram_reg))
420 regulator_put(sram_reg);
421 if (!IS_ERR(cpu_clk))
422 clk_put(cpu_clk);
423 if (!IS_ERR(inter_clk))
424 clk_put(inter_clk);
425
426 return ret;
427}
428
429static void mtk_cpu_dvfs_info_release(struct mtk_cpu_dvfs_info *info)
430{
431 if (!IS_ERR(info->proc_reg))
432 regulator_put(info->proc_reg);
433 if (!IS_ERR(info->sram_reg))
434 regulator_put(info->sram_reg);
435 if (!IS_ERR(info->cpu_clk))
436 clk_put(info->cpu_clk);
437 if (!IS_ERR(info->inter_clk))
438 clk_put(info->inter_clk);
439
440 dev_pm_opp_of_cpumask_remove_table(&info->cpus);
441}
442
443static int mtk_cpufreq_init(struct cpufreq_policy *policy)
444{
445 struct mtk_cpu_dvfs_info *info;
446 struct cpufreq_frequency_table *freq_table;
447 int ret;
448
449 info = mtk_cpu_dvfs_info_lookup(policy->cpu);
450 if (!info) {
451 pr_err("dvfs info for cpu%d is not initialized.\n",
452 policy->cpu);
453 return -EINVAL;
454 }
455
456 ret = dev_pm_opp_init_cpufreq_table(info->cpu_dev, &freq_table);
457 if (ret) {
458 pr_err("failed to init cpufreq table for cpu%d: %d\n",
459 policy->cpu, ret);
460 return ret;
461 }
462
463 cpumask_copy(policy->cpus, &info->cpus);
464 policy->freq_table = freq_table;
465 policy->driver_data = info;
466 policy->clk = info->cpu_clk;
467
468 return 0;
469}
470
471static int mtk_cpufreq_exit(struct cpufreq_policy *policy)
472{
473 struct mtk_cpu_dvfs_info *info = policy->driver_data;
474
475 cpufreq_cooling_unregister(info->cdev);
476 dev_pm_opp_free_cpufreq_table(info->cpu_dev, &policy->freq_table);
477
478 return 0;
479}
480
481static struct cpufreq_driver mtk_cpufreq_driver = {
482 .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK |
483 CPUFREQ_HAVE_GOVERNOR_PER_POLICY,
484 .verify = cpufreq_generic_frequency_table_verify,
485 .target_index = mtk_cpufreq_set_target,
486 .get = cpufreq_generic_get,
487 .init = mtk_cpufreq_init,
488 .exit = mtk_cpufreq_exit,
489 .ready = mtk_cpufreq_ready,
490 .name = "mtk-cpufreq",
491 .attr = cpufreq_generic_attr,
492};
493
494static int mtk_cpufreq_probe(struct platform_device *pdev)
495{
496 struct mtk_cpu_dvfs_info *info, *tmp;
497 int cpu, ret;
498
499 for_each_possible_cpu(cpu) {
500 info = mtk_cpu_dvfs_info_lookup(cpu);
501 if (info)
502 continue;
503
504 info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
505 if (!info) {
506 ret = -ENOMEM;
507 goto release_dvfs_info_list;
508 }
509
510 ret = mtk_cpu_dvfs_info_init(info, cpu);
511 if (ret) {
512 dev_err(&pdev->dev,
513 "failed to initialize dvfs info for cpu%d\n",
514 cpu);
515 goto release_dvfs_info_list;
516 }
517
518 list_add(&info->list_head, &dvfs_info_list);
519 }
520
521 ret = cpufreq_register_driver(&mtk_cpufreq_driver);
522 if (ret) {
523 dev_err(&pdev->dev, "failed to register mtk cpufreq driver\n");
524 goto release_dvfs_info_list;
525 }
526
527 return 0;
528
529release_dvfs_info_list:
530 list_for_each_entry_safe(info, tmp, &dvfs_info_list, list_head) {
531 mtk_cpu_dvfs_info_release(info);
532 list_del(&info->list_head);
533 }
534
535 return ret;
536}
537
538static struct platform_driver mtk_cpufreq_platdrv = {
539 .driver = {
540 .name = "mtk-cpufreq",
541 },
542 .probe = mtk_cpufreq_probe,
543};
544
545/* List of machines supported by this driver */
546static const struct of_device_id mtk_cpufreq_machines[] __initconst = {
547 { .compatible = "mediatek,mt2701", },
548 { .compatible = "mediatek,mt2712", },
549 { .compatible = "mediatek,mt7622", },
550 { .compatible = "mediatek,mt7623", },
551 { .compatible = "mediatek,mt817x", },
552 { .compatible = "mediatek,mt8173", },
553 { .compatible = "mediatek,mt8176", },
554
555 { }
556};
557
558static int __init mtk_cpufreq_driver_init(void)
559{
560 struct device_node *np;
561 const struct of_device_id *match;
562 struct platform_device *pdev;
563 int err;
564
565 np = of_find_node_by_path("/");
566 if (!np)
567 return -ENODEV;
568
569 match = of_match_node(mtk_cpufreq_machines, np);
570 of_node_put(np);
571 if (!match) {
572 pr_debug("Machine is not compatible with mtk-cpufreq\n");
573 return -ENODEV;
574 }
575
576 err = platform_driver_register(&mtk_cpufreq_platdrv);
577 if (err)
578 return err;
579
580 /*
581 * Since there's no place to hold device registration code and no
582 * device tree based way to match cpufreq driver yet, both the driver
583 * and the device registration codes are put here to handle defer
584 * probing.
585 */
586 pdev = platform_device_register_simple("mtk-cpufreq", -1, NULL, 0);
587 if (IS_ERR(pdev)) {
588 pr_err("failed to register mtk-cpufreq platform device\n");
589 return PTR_ERR(pdev);
590 }
591
592 return 0;
593}
594device_initcall(mtk_cpufreq_driver_init);
595
596MODULE_DESCRIPTION("MediaTek CPUFreq driver");
597MODULE_AUTHOR("Pi-Cheng Chen <pi-cheng.chen@linaro.org>");
598MODULE_LICENSE("GPL v2");