xref: /linux/drivers/cpufreq/mediatek-cpufreq.c (revision 24168c5e6dfbdd5b414f048f47f75d64533296ca)
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 
19 struct 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  */
39 struct 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 
62 static struct platform_device *cpufreq_pdev;
63 
64 static LIST_HEAD(dvfs_info_list);
65 
66 static 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 
78 static 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 
162 static 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 
178 static 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 
200 static 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 
310 out:
311 	mutex_unlock(&info->reg_lock);
312 
313 	return ret;
314 }
315 
316 static 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 
368 static 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 
385 static 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 
525 out_disable_inter_clock:
526 	clk_disable_unprepare(info->inter_clk);
527 
528 out_disable_mux_clock:
529 	clk_disable_unprepare(info->cpu_clk);
530 
531 out_free_opp_table:
532 	dev_pm_opp_of_cpumask_remove_table(&info->cpus);
533 
534 out_disable_sram_reg:
535 	if (info->sram_reg)
536 		regulator_disable(info->sram_reg);
537 
538 out_free_sram_reg:
539 	if (info->sram_reg)
540 		regulator_put(info->sram_reg);
541 
542 out_disable_proc_reg:
543 	regulator_disable(info->proc_reg);
544 
545 out_free_proc_reg:
546 	regulator_put(info->proc_reg);
547 
548 out_free_inter_clock:
549 	clk_put(info->inter_clk);
550 
551 out_free_mux_clock:
552 	clk_put(info->cpu_clk);
553 
554 	return ret;
555 }
556 
557 static 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 
573 static 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 
602 static 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 
611 static 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 
625 static 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 
669 release_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 
678 static struct platform_driver mtk_cpufreq_platdrv = {
679 	.driver = {
680 		.name	= "mtk-cpufreq",
681 	},
682 	.probe		= mtk_cpufreq_probe,
683 };
684 
685 static 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 
694 static 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 
703 static 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 
710 static const struct mtk_cpufreq_platform_data mt7988_platform_data = {
711 	.min_volt_shift = 100000,
712 	.max_volt_shift = 200000,
713 	.proc_max_volt = 900000,
714 	.sram_min_volt = 0,
715 	.sram_max_volt = 1150000,
716 	.ccifreq_supported = true,
717 };
718 
719 static const struct mtk_cpufreq_platform_data mt8183_platform_data = {
720 	.min_volt_shift = 100000,
721 	.max_volt_shift = 200000,
722 	.proc_max_volt = 1150000,
723 	.sram_min_volt = 0,
724 	.sram_max_volt = 1150000,
725 	.ccifreq_supported = true,
726 };
727 
728 static const struct mtk_cpufreq_platform_data mt8186_platform_data = {
729 	.min_volt_shift = 100000,
730 	.max_volt_shift = 250000,
731 	.proc_max_volt = 1118750,
732 	.sram_min_volt = 850000,
733 	.sram_max_volt = 1118750,
734 	.ccifreq_supported = true,
735 };
736 
737 static const struct mtk_cpufreq_platform_data mt8516_platform_data = {
738 	.min_volt_shift = 100000,
739 	.max_volt_shift = 200000,
740 	.proc_max_volt = 1310000,
741 	.sram_min_volt = 0,
742 	.sram_max_volt = 1310000,
743 	.ccifreq_supported = false,
744 };
745 
746 /* List of machines supported by this driver */
747 static const struct of_device_id mtk_cpufreq_machines[] __initconst = {
748 	{ .compatible = "mediatek,mt2701", .data = &mt2701_platform_data },
749 	{ .compatible = "mediatek,mt2712", .data = &mt2701_platform_data },
750 	{ .compatible = "mediatek,mt7622", .data = &mt7622_platform_data },
751 	{ .compatible = "mediatek,mt7623", .data = &mt7623_platform_data },
752 	{ .compatible = "mediatek,mt7988a", .data = &mt7988_platform_data },
753 	{ .compatible = "mediatek,mt8167", .data = &mt8516_platform_data },
754 	{ .compatible = "mediatek,mt817x", .data = &mt2701_platform_data },
755 	{ .compatible = "mediatek,mt8173", .data = &mt2701_platform_data },
756 	{ .compatible = "mediatek,mt8176", .data = &mt2701_platform_data },
757 	{ .compatible = "mediatek,mt8183", .data = &mt8183_platform_data },
758 	{ .compatible = "mediatek,mt8186", .data = &mt8186_platform_data },
759 	{ .compatible = "mediatek,mt8365", .data = &mt2701_platform_data },
760 	{ .compatible = "mediatek,mt8516", .data = &mt8516_platform_data },
761 	{ }
762 };
763 MODULE_DEVICE_TABLE(of, mtk_cpufreq_machines);
764 
765 static int __init mtk_cpufreq_driver_init(void)
766 {
767 	struct device_node *np;
768 	const struct of_device_id *match;
769 	const struct mtk_cpufreq_platform_data *data;
770 	int err;
771 
772 	np = of_find_node_by_path("/");
773 	if (!np)
774 		return -ENODEV;
775 
776 	match = of_match_node(mtk_cpufreq_machines, np);
777 	of_node_put(np);
778 	if (!match) {
779 		pr_debug("Machine is not compatible with mtk-cpufreq\n");
780 		return -ENODEV;
781 	}
782 	data = match->data;
783 
784 	err = platform_driver_register(&mtk_cpufreq_platdrv);
785 	if (err)
786 		return err;
787 
788 	/*
789 	 * Since there's no place to hold device registration code and no
790 	 * device tree based way to match cpufreq driver yet, both the driver
791 	 * and the device registration codes are put here to handle defer
792 	 * probing.
793 	 */
794 	cpufreq_pdev = platform_device_register_data(NULL, "mtk-cpufreq", -1,
795 						     data, sizeof(*data));
796 	if (IS_ERR(cpufreq_pdev)) {
797 		pr_err("failed to register mtk-cpufreq platform device\n");
798 		platform_driver_unregister(&mtk_cpufreq_platdrv);
799 		return PTR_ERR(cpufreq_pdev);
800 	}
801 
802 	return 0;
803 }
804 module_init(mtk_cpufreq_driver_init)
805 
806 static void __exit mtk_cpufreq_driver_exit(void)
807 {
808 	platform_device_unregister(cpufreq_pdev);
809 	platform_driver_unregister(&mtk_cpufreq_platdrv);
810 }
811 module_exit(mtk_cpufreq_driver_exit)
812 
813 MODULE_DESCRIPTION("MediaTek CPUFreq driver");
814 MODULE_AUTHOR("Pi-Cheng Chen <pi-cheng.chen@linaro.org>");
815 MODULE_LICENSE("GPL v2");
816