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 #define DYNAMIC_POWER "dynamic-power-coefficient"
317 
318 static int mtk_cpufreq_opp_notifier(struct notifier_block *nb,
319 				    unsigned long event, void *data)
320 {
321 	struct dev_pm_opp *opp = data;
322 	struct dev_pm_opp *new_opp;
323 	struct mtk_cpu_dvfs_info *info;
324 	unsigned long freq, volt;
325 	struct cpufreq_policy *policy;
326 	int ret = 0;
327 
328 	info = container_of(nb, struct mtk_cpu_dvfs_info, opp_nb);
329 
330 	if (event == OPP_EVENT_ADJUST_VOLTAGE) {
331 		freq = dev_pm_opp_get_freq(opp);
332 
333 		mutex_lock(&info->reg_lock);
334 		if (info->current_freq == freq) {
335 			volt = dev_pm_opp_get_voltage(opp);
336 			ret = mtk_cpufreq_set_voltage(info, volt);
337 			if (ret)
338 				dev_err(info->cpu_dev,
339 					"failed to scale voltage: %d\n", ret);
340 		}
341 		mutex_unlock(&info->reg_lock);
342 	} else if (event == OPP_EVENT_DISABLE) {
343 		freq = dev_pm_opp_get_freq(opp);
344 
345 		/* case of current opp item is disabled */
346 		if (info->current_freq == freq) {
347 			freq = 1;
348 			new_opp = dev_pm_opp_find_freq_ceil(info->cpu_dev,
349 							    &freq);
350 			if (IS_ERR(new_opp)) {
351 				dev_err(info->cpu_dev,
352 					"all opp items are disabled\n");
353 				ret = PTR_ERR(new_opp);
354 				return notifier_from_errno(ret);
355 			}
356 
357 			dev_pm_opp_put(new_opp);
358 			policy = cpufreq_cpu_get(info->opp_cpu);
359 			if (policy) {
360 				cpufreq_driver_target(policy, freq / 1000,
361 						      CPUFREQ_RELATION_L);
362 				cpufreq_cpu_put(policy);
363 			}
364 		}
365 	}
366 
367 	return notifier_from_errno(ret);
368 }
369 
370 static struct device *of_get_cci(struct device *cpu_dev)
371 {
372 	struct device_node *np;
373 	struct platform_device *pdev;
374 
375 	np = of_parse_phandle(cpu_dev->of_node, "mediatek,cci", 0);
376 	if (IS_ERR_OR_NULL(np))
377 		return NULL;
378 
379 	pdev = of_find_device_by_node(np);
380 	of_node_put(np);
381 	if (IS_ERR_OR_NULL(pdev))
382 		return NULL;
383 
384 	return &pdev->dev;
385 }
386 
387 static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
388 {
389 	struct device *cpu_dev;
390 	struct dev_pm_opp *opp;
391 	unsigned long rate;
392 	int ret;
393 
394 	cpu_dev = get_cpu_device(cpu);
395 	if (!cpu_dev) {
396 		dev_err(cpu_dev, "failed to get cpu%d device\n", cpu);
397 		return -ENODEV;
398 	}
399 	info->cpu_dev = cpu_dev;
400 
401 	info->ccifreq_bound = false;
402 	if (info->soc_data->ccifreq_supported) {
403 		info->cci_dev = of_get_cci(info->cpu_dev);
404 		if (IS_ERR_OR_NULL(info->cci_dev)) {
405 			ret = PTR_ERR(info->cci_dev);
406 			dev_err(cpu_dev, "cpu%d: failed to get cci device\n", cpu);
407 			return -ENODEV;
408 		}
409 	}
410 
411 	info->cpu_clk = clk_get(cpu_dev, "cpu");
412 	if (IS_ERR(info->cpu_clk)) {
413 		ret = PTR_ERR(info->cpu_clk);
414 		return dev_err_probe(cpu_dev, ret,
415 				     "cpu%d: failed to get cpu clk\n", cpu);
416 	}
417 
418 	info->inter_clk = clk_get(cpu_dev, "intermediate");
419 	if (IS_ERR(info->inter_clk)) {
420 		ret = PTR_ERR(info->inter_clk);
421 		dev_err_probe(cpu_dev, ret,
422 			      "cpu%d: failed to get intermediate clk\n", cpu);
423 		goto out_free_resources;
424 	}
425 
426 	info->proc_reg = regulator_get_optional(cpu_dev, "proc");
427 	if (IS_ERR(info->proc_reg)) {
428 		ret = PTR_ERR(info->proc_reg);
429 		dev_err_probe(cpu_dev, ret,
430 			      "cpu%d: failed to get proc regulator\n", cpu);
431 		goto out_free_resources;
432 	}
433 
434 	ret = regulator_enable(info->proc_reg);
435 	if (ret) {
436 		dev_warn(cpu_dev, "cpu%d: failed to enable vproc\n", cpu);
437 		goto out_free_resources;
438 	}
439 
440 	/* Both presence and absence of sram regulator are valid cases. */
441 	info->sram_reg = regulator_get_optional(cpu_dev, "sram");
442 	if (IS_ERR(info->sram_reg))
443 		info->sram_reg = NULL;
444 	else {
445 		ret = regulator_enable(info->sram_reg);
446 		if (ret) {
447 			dev_warn(cpu_dev, "cpu%d: failed to enable vsram\n", cpu);
448 			goto out_free_resources;
449 		}
450 	}
451 
452 	/* Get OPP-sharing information from "operating-points-v2" bindings */
453 	ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, &info->cpus);
454 	if (ret) {
455 		dev_err(cpu_dev,
456 			"cpu%d: failed to get OPP-sharing information\n", cpu);
457 		goto out_free_resources;
458 	}
459 
460 	ret = dev_pm_opp_of_cpumask_add_table(&info->cpus);
461 	if (ret) {
462 		dev_warn(cpu_dev, "cpu%d: no OPP table\n", cpu);
463 		goto out_free_resources;
464 	}
465 
466 	ret = clk_prepare_enable(info->cpu_clk);
467 	if (ret)
468 		goto out_free_opp_table;
469 
470 	ret = clk_prepare_enable(info->inter_clk);
471 	if (ret)
472 		goto out_disable_mux_clock;
473 
474 	if (info->soc_data->ccifreq_supported) {
475 		info->vproc_on_boot = regulator_get_voltage(info->proc_reg);
476 		if (info->vproc_on_boot < 0) {
477 			dev_err(info->cpu_dev,
478 				"invalid Vproc value: %d\n", info->vproc_on_boot);
479 			goto out_disable_inter_clock;
480 		}
481 	}
482 
483 	/* Search a safe voltage for intermediate frequency. */
484 	rate = clk_get_rate(info->inter_clk);
485 	opp = dev_pm_opp_find_freq_ceil(cpu_dev, &rate);
486 	if (IS_ERR(opp)) {
487 		dev_err(cpu_dev, "cpu%d: failed to get intermediate opp\n", cpu);
488 		ret = PTR_ERR(opp);
489 		goto out_disable_inter_clock;
490 	}
491 	info->intermediate_voltage = dev_pm_opp_get_voltage(opp);
492 	dev_pm_opp_put(opp);
493 
494 	mutex_init(&info->reg_lock);
495 	info->current_freq = clk_get_rate(info->cpu_clk);
496 
497 	info->opp_cpu = cpu;
498 	info->opp_nb.notifier_call = mtk_cpufreq_opp_notifier;
499 	ret = dev_pm_opp_register_notifier(cpu_dev, &info->opp_nb);
500 	if (ret) {
501 		dev_err(cpu_dev, "cpu%d: failed to register opp notifier\n", cpu);
502 		goto out_disable_inter_clock;
503 	}
504 
505 	/*
506 	 * If SRAM regulator is present, software "voltage tracking" is needed
507 	 * for this CPU power domain.
508 	 */
509 	info->need_voltage_tracking = (info->sram_reg != NULL);
510 
511 	/*
512 	 * We assume min voltage is 0 and tracking target voltage using
513 	 * min_volt_shift for each iteration.
514 	 * The vtrack_max is 3 times of expeted iteration count.
515 	 */
516 	info->vtrack_max = 3 * DIV_ROUND_UP(max(info->soc_data->sram_max_volt,
517 						info->soc_data->proc_max_volt),
518 					    info->soc_data->min_volt_shift);
519 
520 	return 0;
521 
522 out_disable_inter_clock:
523 	clk_disable_unprepare(info->inter_clk);
524 
525 out_disable_mux_clock:
526 	clk_disable_unprepare(info->cpu_clk);
527 
528 out_free_opp_table:
529 	dev_pm_opp_of_cpumask_remove_table(&info->cpus);
530 
531 out_free_resources:
532 	if (regulator_is_enabled(info->proc_reg))
533 		regulator_disable(info->proc_reg);
534 	if (info->sram_reg && regulator_is_enabled(info->sram_reg))
535 		regulator_disable(info->sram_reg);
536 
537 	if (!IS_ERR(info->proc_reg))
538 		regulator_put(info->proc_reg);
539 	if (!IS_ERR(info->sram_reg))
540 		regulator_put(info->sram_reg);
541 	if (!IS_ERR(info->cpu_clk))
542 		clk_put(info->cpu_clk);
543 	if (!IS_ERR(info->inter_clk))
544 		clk_put(info->inter_clk);
545 
546 	return ret;
547 }
548 
549 static void mtk_cpu_dvfs_info_release(struct mtk_cpu_dvfs_info *info)
550 {
551 	if (!IS_ERR(info->proc_reg)) {
552 		regulator_disable(info->proc_reg);
553 		regulator_put(info->proc_reg);
554 	}
555 	if (!IS_ERR(info->sram_reg)) {
556 		regulator_disable(info->sram_reg);
557 		regulator_put(info->sram_reg);
558 	}
559 	if (!IS_ERR(info->cpu_clk)) {
560 		clk_disable_unprepare(info->cpu_clk);
561 		clk_put(info->cpu_clk);
562 	}
563 	if (!IS_ERR(info->inter_clk)) {
564 		clk_disable_unprepare(info->inter_clk);
565 		clk_put(info->inter_clk);
566 	}
567 
568 	dev_pm_opp_of_cpumask_remove_table(&info->cpus);
569 	dev_pm_opp_unregister_notifier(info->cpu_dev, &info->opp_nb);
570 }
571 
572 static int mtk_cpufreq_init(struct cpufreq_policy *policy)
573 {
574 	struct mtk_cpu_dvfs_info *info;
575 	struct cpufreq_frequency_table *freq_table;
576 	int ret;
577 
578 	info = mtk_cpu_dvfs_info_lookup(policy->cpu);
579 	if (!info) {
580 		pr_err("dvfs info for cpu%d is not initialized.\n",
581 			policy->cpu);
582 		return -EINVAL;
583 	}
584 
585 	ret = dev_pm_opp_init_cpufreq_table(info->cpu_dev, &freq_table);
586 	if (ret) {
587 		dev_err(info->cpu_dev,
588 			"failed to init cpufreq table for cpu%d: %d\n",
589 			policy->cpu, ret);
590 		return ret;
591 	}
592 
593 	cpumask_copy(policy->cpus, &info->cpus);
594 	policy->freq_table = freq_table;
595 	policy->driver_data = info;
596 	policy->clk = info->cpu_clk;
597 
598 	return 0;
599 }
600 
601 static int mtk_cpufreq_exit(struct cpufreq_policy *policy)
602 {
603 	struct mtk_cpu_dvfs_info *info = policy->driver_data;
604 
605 	dev_pm_opp_free_cpufreq_table(info->cpu_dev, &policy->freq_table);
606 
607 	return 0;
608 }
609 
610 static struct cpufreq_driver mtk_cpufreq_driver = {
611 	.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK |
612 		 CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
613 		 CPUFREQ_IS_COOLING_DEV,
614 	.verify = cpufreq_generic_frequency_table_verify,
615 	.target_index = mtk_cpufreq_set_target,
616 	.get = cpufreq_generic_get,
617 	.init = mtk_cpufreq_init,
618 	.exit = mtk_cpufreq_exit,
619 	.register_em = cpufreq_register_em_with_opp,
620 	.name = "mtk-cpufreq",
621 	.attr = cpufreq_generic_attr,
622 };
623 
624 static int mtk_cpufreq_probe(struct platform_device *pdev)
625 {
626 	const struct mtk_cpufreq_platform_data *data;
627 	struct mtk_cpu_dvfs_info *info, *tmp;
628 	int cpu, ret;
629 
630 	data = dev_get_platdata(&pdev->dev);
631 	if (!data) {
632 		dev_err(&pdev->dev,
633 			"failed to get mtk cpufreq platform data\n");
634 		return -ENODEV;
635 	}
636 
637 	for_each_possible_cpu(cpu) {
638 		info = mtk_cpu_dvfs_info_lookup(cpu);
639 		if (info)
640 			continue;
641 
642 		info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
643 		if (!info) {
644 			ret = -ENOMEM;
645 			goto release_dvfs_info_list;
646 		}
647 
648 		info->soc_data = data;
649 		ret = mtk_cpu_dvfs_info_init(info, cpu);
650 		if (ret) {
651 			dev_err(&pdev->dev,
652 				"failed to initialize dvfs info for cpu%d\n",
653 				cpu);
654 			goto release_dvfs_info_list;
655 		}
656 
657 		list_add(&info->list_head, &dvfs_info_list);
658 	}
659 
660 	ret = cpufreq_register_driver(&mtk_cpufreq_driver);
661 	if (ret) {
662 		dev_err(&pdev->dev, "failed to register mtk cpufreq driver\n");
663 		goto release_dvfs_info_list;
664 	}
665 
666 	return 0;
667 
668 release_dvfs_info_list:
669 	list_for_each_entry_safe(info, tmp, &dvfs_info_list, list_head) {
670 		mtk_cpu_dvfs_info_release(info);
671 		list_del(&info->list_head);
672 	}
673 
674 	return ret;
675 }
676 
677 static struct platform_driver mtk_cpufreq_platdrv = {
678 	.driver = {
679 		.name	= "mtk-cpufreq",
680 	},
681 	.probe		= mtk_cpufreq_probe,
682 };
683 
684 static const struct mtk_cpufreq_platform_data mt2701_platform_data = {
685 	.min_volt_shift = 100000,
686 	.max_volt_shift = 200000,
687 	.proc_max_volt = 1150000,
688 	.sram_min_volt = 0,
689 	.sram_max_volt = 1150000,
690 	.ccifreq_supported = false,
691 };
692 
693 static const struct mtk_cpufreq_platform_data mt8183_platform_data = {
694 	.min_volt_shift = 100000,
695 	.max_volt_shift = 200000,
696 	.proc_max_volt = 1150000,
697 	.sram_min_volt = 0,
698 	.sram_max_volt = 1150000,
699 	.ccifreq_supported = true,
700 };
701 
702 static const struct mtk_cpufreq_platform_data mt8186_platform_data = {
703 	.min_volt_shift = 100000,
704 	.max_volt_shift = 250000,
705 	.proc_max_volt = 1118750,
706 	.sram_min_volt = 850000,
707 	.sram_max_volt = 1118750,
708 	.ccifreq_supported = true,
709 };
710 
711 /* List of machines supported by this driver */
712 static const struct of_device_id mtk_cpufreq_machines[] __initconst = {
713 	{ .compatible = "mediatek,mt2701", .data = &mt2701_platform_data },
714 	{ .compatible = "mediatek,mt2712", .data = &mt2701_platform_data },
715 	{ .compatible = "mediatek,mt7622", .data = &mt2701_platform_data },
716 	{ .compatible = "mediatek,mt7623", .data = &mt2701_platform_data },
717 	{ .compatible = "mediatek,mt8167", .data = &mt2701_platform_data },
718 	{ .compatible = "mediatek,mt817x", .data = &mt2701_platform_data },
719 	{ .compatible = "mediatek,mt8173", .data = &mt2701_platform_data },
720 	{ .compatible = "mediatek,mt8176", .data = &mt2701_platform_data },
721 	{ .compatible = "mediatek,mt8183", .data = &mt8183_platform_data },
722 	{ .compatible = "mediatek,mt8186", .data = &mt8186_platform_data },
723 	{ .compatible = "mediatek,mt8365", .data = &mt2701_platform_data },
724 	{ .compatible = "mediatek,mt8516", .data = &mt2701_platform_data },
725 	{ }
726 };
727 MODULE_DEVICE_TABLE(of, mtk_cpufreq_machines);
728 
729 static int __init mtk_cpufreq_driver_init(void)
730 {
731 	struct device_node *np;
732 	const struct of_device_id *match;
733 	const struct mtk_cpufreq_platform_data *data;
734 	int err;
735 
736 	np = of_find_node_by_path("/");
737 	if (!np)
738 		return -ENODEV;
739 
740 	match = of_match_node(mtk_cpufreq_machines, np);
741 	of_node_put(np);
742 	if (!match) {
743 		pr_debug("Machine is not compatible with mtk-cpufreq\n");
744 		return -ENODEV;
745 	}
746 	data = match->data;
747 
748 	err = platform_driver_register(&mtk_cpufreq_platdrv);
749 	if (err)
750 		return err;
751 
752 	/*
753 	 * Since there's no place to hold device registration code and no
754 	 * device tree based way to match cpufreq driver yet, both the driver
755 	 * and the device registration codes are put here to handle defer
756 	 * probing.
757 	 */
758 	cpufreq_pdev = platform_device_register_data(NULL, "mtk-cpufreq", -1,
759 						     data, sizeof(*data));
760 	if (IS_ERR(cpufreq_pdev)) {
761 		pr_err("failed to register mtk-cpufreq platform device\n");
762 		platform_driver_unregister(&mtk_cpufreq_platdrv);
763 		return PTR_ERR(cpufreq_pdev);
764 	}
765 
766 	return 0;
767 }
768 module_init(mtk_cpufreq_driver_init)
769 
770 static void __exit mtk_cpufreq_driver_exit(void)
771 {
772 	platform_device_unregister(cpufreq_pdev);
773 	platform_driver_unregister(&mtk_cpufreq_platdrv);
774 }
775 module_exit(mtk_cpufreq_driver_exit)
776 
777 MODULE_DESCRIPTION("MediaTek CPUFreq driver");
778 MODULE_AUTHOR("Pi-Cheng Chen <pi-cheng.chen@linaro.org>");
779 MODULE_LICENSE("GPL v2");
780