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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * pwm-fan.c - Hwmon driver for fans connected to PWM lines.
4 *
5 * Copyright (c) 2014 Samsung Electronics Co., Ltd.
6 *
7 * Author: Kamil Debski <k.debski@samsung.com>
8 */
9
10#include <linux/delay.h>
11#include <linux/hwmon.h>
12#include <linux/interrupt.h>
13#include <linux/mod_devicetable.h>
14#include <linux/module.h>
15#include <linux/mutex.h>
16#include <linux/platform_device.h>
17#include <linux/property.h>
18#include <linux/pwm.h>
19#include <linux/regulator/consumer.h>
20#include <linux/sysfs.h>
21#include <linux/thermal.h>
22#include <linux/timer.h>
23
24#define MAX_PWM 255
25
26struct pwm_fan_tach {
27 int irq;
28 atomic_t pulses;
29 unsigned int rpm;
30};
31
32enum pwm_fan_enable_mode {
33 pwm_off_reg_off,
34 pwm_disable_reg_enable,
35 pwm_enable_reg_enable,
36 pwm_disable_reg_disable,
37};
38
39struct pwm_fan_ctx {
40 struct device *dev;
41
42 struct mutex lock;
43 struct pwm_device *pwm;
44 struct pwm_state pwm_state;
45 struct regulator *reg_en;
46 enum pwm_fan_enable_mode enable_mode;
47 bool regulator_enabled;
48 bool enabled;
49
50 int tach_count;
51 struct pwm_fan_tach *tachs;
52 u32 *pulses_per_revolution;
53 ktime_t sample_start;
54 struct timer_list rpm_timer;
55
56 unsigned int pwm_value;
57 unsigned int pwm_fan_state;
58 unsigned int pwm_fan_max_state;
59 unsigned int *pwm_fan_cooling_levels;
60 struct thermal_cooling_device *cdev;
61
62 struct hwmon_chip_info info;
63 struct hwmon_channel_info fan_channel;
64
65 u64 pwm_duty_cycle_from_stopped;
66 u32 pwm_usec_from_stopped;
67};
68
69/* This handler assumes self resetting edge triggered interrupt. */
70static irqreturn_t pulse_handler(int irq, void *dev_id)
71{
72 struct pwm_fan_tach *tach = dev_id;
73
74 atomic_inc(&tach->pulses);
75
76 return IRQ_HANDLED;
77}
78
79static void sample_timer(struct timer_list *t)
80{
81 struct pwm_fan_ctx *ctx = from_timer(ctx, t, rpm_timer);
82 unsigned int delta = ktime_ms_delta(ktime_get(), ctx->sample_start);
83 int i;
84
85 if (delta) {
86 for (i = 0; i < ctx->tach_count; i++) {
87 struct pwm_fan_tach *tach = &ctx->tachs[i];
88 int pulses;
89
90 pulses = atomic_read(&tach->pulses);
91 atomic_sub(pulses, &tach->pulses);
92 tach->rpm = (unsigned int)(pulses * 1000 * 60) /
93 (ctx->pulses_per_revolution[i] * delta);
94 }
95
96 ctx->sample_start = ktime_get();
97 }
98
99 mod_timer(&ctx->rpm_timer, jiffies + HZ);
100}
101
102static void pwm_fan_enable_mode_2_state(int enable_mode,
103 struct pwm_state *state,
104 bool *enable_regulator)
105{
106 switch (enable_mode) {
107 case pwm_disable_reg_enable:
108 /* disable pwm, keep regulator enabled */
109 state->enabled = false;
110 *enable_regulator = true;
111 break;
112 case pwm_enable_reg_enable:
113 /* keep pwm and regulator enabled */
114 state->enabled = true;
115 *enable_regulator = true;
116 break;
117 case pwm_off_reg_off:
118 case pwm_disable_reg_disable:
119 /* disable pwm and regulator */
120 state->enabled = false;
121 *enable_regulator = false;
122 }
123}
124
125static int pwm_fan_switch_power(struct pwm_fan_ctx *ctx, bool on)
126{
127 int ret = 0;
128
129 if (!ctx->reg_en)
130 return ret;
131
132 if (!ctx->regulator_enabled && on) {
133 ret = regulator_enable(ctx->reg_en);
134 if (ret == 0)
135 ctx->regulator_enabled = true;
136 } else if (ctx->regulator_enabled && !on) {
137 ret = regulator_disable(ctx->reg_en);
138 if (ret == 0)
139 ctx->regulator_enabled = false;
140 }
141 return ret;
142}
143
144static int pwm_fan_power_on(struct pwm_fan_ctx *ctx)
145{
146 struct pwm_state *state = &ctx->pwm_state;
147 int ret;
148
149 if (ctx->enabled)
150 return 0;
151
152 ret = pwm_fan_switch_power(ctx, true);
153 if (ret < 0) {
154 dev_err(ctx->dev, "failed to enable power supply\n");
155 return ret;
156 }
157
158 state->enabled = true;
159 ret = pwm_apply_might_sleep(ctx->pwm, state);
160 if (ret) {
161 dev_err(ctx->dev, "failed to enable PWM\n");
162 goto disable_regulator;
163 }
164
165 ctx->enabled = true;
166
167 return 0;
168
169disable_regulator:
170 pwm_fan_switch_power(ctx, false);
171 return ret;
172}
173
174static int pwm_fan_power_off(struct pwm_fan_ctx *ctx, bool force_disable)
175{
176 struct pwm_state *state = &ctx->pwm_state;
177 bool enable_regulator = false;
178 int ret;
179
180 if (!ctx->enabled)
181 return 0;
182
183 pwm_fan_enable_mode_2_state(ctx->enable_mode,
184 state,
185 &enable_regulator);
186
187 if (force_disable)
188 state->enabled = false;
189 state->duty_cycle = 0;
190 ret = pwm_apply_might_sleep(ctx->pwm, state);
191 if (ret) {
192 dev_err(ctx->dev, "failed to disable PWM\n");
193 return ret;
194 }
195
196 pwm_fan_switch_power(ctx, enable_regulator);
197
198 ctx->enabled = false;
199
200 return 0;
201}
202
203static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
204{
205 struct pwm_state *state = &ctx->pwm_state;
206 unsigned long final_pwm = pwm;
207 unsigned long period;
208 bool update = false;
209 int ret = 0;
210
211 if (pwm > 0) {
212 if (ctx->enable_mode == pwm_off_reg_off)
213 /* pwm-fan hard disabled */
214 return 0;
215
216 period = state->period;
217 update = state->duty_cycle < ctx->pwm_duty_cycle_from_stopped;
218 if (update)
219 state->duty_cycle = ctx->pwm_duty_cycle_from_stopped;
220 else
221 state->duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM);
222 ret = pwm_apply_might_sleep(ctx->pwm, state);
223 if (ret)
224 return ret;
225 ret = pwm_fan_power_on(ctx);
226 if (!ret && update) {
227 pwm = final_pwm;
228 state->duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM);
229 usleep_range(ctx->pwm_usec_from_stopped,
230 ctx->pwm_usec_from_stopped * 2);
231 ret = pwm_apply_might_sleep(ctx->pwm, state);
232 }
233 } else {
234 ret = pwm_fan_power_off(ctx, false);
235 }
236 if (!ret)
237 ctx->pwm_value = pwm;
238
239 return ret;
240}
241
242static int set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
243{
244 int ret;
245
246 mutex_lock(&ctx->lock);
247 ret = __set_pwm(ctx, pwm);
248 mutex_unlock(&ctx->lock);
249
250 return ret;
251}
252
253static void pwm_fan_update_state(struct pwm_fan_ctx *ctx, unsigned long pwm)
254{
255 int i;
256
257 for (i = 0; i < ctx->pwm_fan_max_state; ++i)
258 if (pwm < ctx->pwm_fan_cooling_levels[i + 1])
259 break;
260
261 ctx->pwm_fan_state = i;
262}
263
264static int pwm_fan_update_enable(struct pwm_fan_ctx *ctx, long val)
265{
266 int ret = 0;
267 int old_val;
268
269 mutex_lock(&ctx->lock);
270
271 if (ctx->enable_mode == val)
272 goto out;
273
274 old_val = ctx->enable_mode;
275 ctx->enable_mode = val;
276
277 if (val == 0) {
278 /* Disable pwm-fan unconditionally */
279 if (ctx->enabled)
280 ret = __set_pwm(ctx, 0);
281 else
282 ret = pwm_fan_switch_power(ctx, false);
283 if (ret)
284 ctx->enable_mode = old_val;
285 pwm_fan_update_state(ctx, 0);
286 } else {
287 /*
288 * Change PWM and/or regulator state if currently disabled
289 * Nothing to do if currently enabled
290 */
291 if (!ctx->enabled) {
292 struct pwm_state *state = &ctx->pwm_state;
293 bool enable_regulator = false;
294
295 state->duty_cycle = 0;
296 pwm_fan_enable_mode_2_state(val,
297 state,
298 &enable_regulator);
299
300 pwm_apply_might_sleep(ctx->pwm, state);
301 pwm_fan_switch_power(ctx, enable_regulator);
302 pwm_fan_update_state(ctx, 0);
303 }
304 }
305out:
306 mutex_unlock(&ctx->lock);
307
308 return ret;
309}
310
311static int pwm_fan_write(struct device *dev, enum hwmon_sensor_types type,
312 u32 attr, int channel, long val)
313{
314 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
315 int ret;
316
317 switch (attr) {
318 case hwmon_pwm_input:
319 if (val < 0 || val > MAX_PWM)
320 return -EINVAL;
321 ret = set_pwm(ctx, val);
322 if (ret)
323 return ret;
324 pwm_fan_update_state(ctx, val);
325 break;
326 case hwmon_pwm_enable:
327 if (val < 0 || val > 3)
328 ret = -EINVAL;
329 else
330 ret = pwm_fan_update_enable(ctx, val);
331
332 return ret;
333 default:
334 return -EOPNOTSUPP;
335 }
336
337 return 0;
338}
339
340static int pwm_fan_read(struct device *dev, enum hwmon_sensor_types type,
341 u32 attr, int channel, long *val)
342{
343 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
344
345 switch (type) {
346 case hwmon_pwm:
347 switch (attr) {
348 case hwmon_pwm_input:
349 *val = ctx->pwm_value;
350 return 0;
351 case hwmon_pwm_enable:
352 *val = ctx->enable_mode;
353 return 0;
354 }
355 return -EOPNOTSUPP;
356 case hwmon_fan:
357 *val = ctx->tachs[channel].rpm;
358 return 0;
359
360 default:
361 return -ENOTSUPP;
362 }
363}
364
365static umode_t pwm_fan_is_visible(const void *data,
366 enum hwmon_sensor_types type,
367 u32 attr, int channel)
368{
369 switch (type) {
370 case hwmon_pwm:
371 return 0644;
372
373 case hwmon_fan:
374 return 0444;
375
376 default:
377 return 0;
378 }
379}
380
381static const struct hwmon_ops pwm_fan_hwmon_ops = {
382 .is_visible = pwm_fan_is_visible,
383 .read = pwm_fan_read,
384 .write = pwm_fan_write,
385};
386
387/* thermal cooling device callbacks */
388static int pwm_fan_get_max_state(struct thermal_cooling_device *cdev,
389 unsigned long *state)
390{
391 struct pwm_fan_ctx *ctx = cdev->devdata;
392
393 if (!ctx)
394 return -EINVAL;
395
396 *state = ctx->pwm_fan_max_state;
397
398 return 0;
399}
400
401static int pwm_fan_get_cur_state(struct thermal_cooling_device *cdev,
402 unsigned long *state)
403{
404 struct pwm_fan_ctx *ctx = cdev->devdata;
405
406 if (!ctx)
407 return -EINVAL;
408
409 *state = ctx->pwm_fan_state;
410
411 return 0;
412}
413
414static int
415pwm_fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)
416{
417 struct pwm_fan_ctx *ctx = cdev->devdata;
418 int ret;
419
420 if (!ctx || (state > ctx->pwm_fan_max_state))
421 return -EINVAL;
422
423 if (state == ctx->pwm_fan_state)
424 return 0;
425
426 ret = set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]);
427 if (ret) {
428 dev_err(&cdev->device, "Cannot set pwm!\n");
429 return ret;
430 }
431
432 ctx->pwm_fan_state = state;
433
434 return ret;
435}
436
437static const struct thermal_cooling_device_ops pwm_fan_cooling_ops = {
438 .get_max_state = pwm_fan_get_max_state,
439 .get_cur_state = pwm_fan_get_cur_state,
440 .set_cur_state = pwm_fan_set_cur_state,
441};
442
443static int pwm_fan_get_cooling_data(struct device *dev, struct pwm_fan_ctx *ctx)
444{
445 int num, i, ret;
446
447 if (!device_property_present(dev, "cooling-levels"))
448 return 0;
449
450 ret = device_property_count_u32(dev, "cooling-levels");
451 if (ret <= 0) {
452 dev_err(dev, "Wrong data!\n");
453 return ret ? : -EINVAL;
454 }
455
456 num = ret;
457 ctx->pwm_fan_cooling_levels = devm_kcalloc(dev, num, sizeof(u32),
458 GFP_KERNEL);
459 if (!ctx->pwm_fan_cooling_levels)
460 return -ENOMEM;
461
462 ret = device_property_read_u32_array(dev, "cooling-levels",
463 ctx->pwm_fan_cooling_levels, num);
464 if (ret) {
465 dev_err(dev, "Property 'cooling-levels' cannot be read!\n");
466 return ret;
467 }
468
469 for (i = 0; i < num; i++) {
470 if (ctx->pwm_fan_cooling_levels[i] > MAX_PWM) {
471 dev_err(dev, "PWM fan state[%d]:%d > %d\n", i,
472 ctx->pwm_fan_cooling_levels[i], MAX_PWM);
473 return -EINVAL;
474 }
475 }
476
477 ctx->pwm_fan_max_state = num - 1;
478
479 return 0;
480}
481
482static void pwm_fan_cleanup(void *__ctx)
483{
484 struct pwm_fan_ctx *ctx = __ctx;
485
486 del_timer_sync(&ctx->rpm_timer);
487 /* Switch off everything */
488 ctx->enable_mode = pwm_disable_reg_disable;
489 pwm_fan_power_off(ctx, true);
490}
491
492static int pwm_fan_probe(struct platform_device *pdev)
493{
494 struct thermal_cooling_device *cdev;
495 struct device *dev = &pdev->dev;
496 struct pwm_fan_ctx *ctx;
497 struct device *hwmon;
498 int ret;
499 const struct hwmon_channel_info **channels;
500 u32 pwm_min_from_stopped = 0;
501 u32 *fan_channel_config;
502 int channel_count = 1; /* We always have a PWM channel. */
503 int i;
504
505 ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
506 if (!ctx)
507 return -ENOMEM;
508
509 mutex_init(&ctx->lock);
510
511 ctx->dev = &pdev->dev;
512 ctx->pwm = devm_pwm_get(dev, NULL);
513 if (IS_ERR(ctx->pwm))
514 return dev_err_probe(dev, PTR_ERR(ctx->pwm), "Could not get PWM\n");
515
516 platform_set_drvdata(pdev, ctx);
517
518 ctx->reg_en = devm_regulator_get_optional(dev, "fan");
519 if (IS_ERR(ctx->reg_en)) {
520 if (PTR_ERR(ctx->reg_en) != -ENODEV)
521 return PTR_ERR(ctx->reg_en);
522
523 ctx->reg_en = NULL;
524 }
525
526 pwm_init_state(ctx->pwm, &ctx->pwm_state);
527
528 /*
529 * PWM fans are controlled solely by the duty cycle of the PWM signal,
530 * they do not care about the exact timing. Thus set usage_power to true
531 * to allow less flexible hardware to work as a PWM source for fan
532 * control.
533 */
534 ctx->pwm_state.usage_power = true;
535
536 /*
537 * set_pwm assumes that MAX_PWM * (period - 1) fits into an unsigned
538 * long. Check this here to prevent the fan running at a too low
539 * frequency.
540 */
541 if (ctx->pwm_state.period > ULONG_MAX / MAX_PWM + 1) {
542 dev_err(dev, "Configured period too big\n");
543 return -EINVAL;
544 }
545
546 ctx->enable_mode = pwm_disable_reg_enable;
547
548 /*
549 * Set duty cycle to maximum allowed and enable PWM output as well as
550 * the regulator. In case of error nothing is changed
551 */
552 ret = set_pwm(ctx, MAX_PWM);
553 if (ret) {
554 dev_err(dev, "Failed to configure PWM: %d\n", ret);
555 return ret;
556 }
557 timer_setup(&ctx->rpm_timer, sample_timer, 0);
558 ret = devm_add_action_or_reset(dev, pwm_fan_cleanup, ctx);
559 if (ret)
560 return ret;
561
562 ctx->tach_count = platform_irq_count(pdev);
563 if (ctx->tach_count < 0)
564 return dev_err_probe(dev, ctx->tach_count,
565 "Could not get number of fan tachometer inputs\n");
566 dev_dbg(dev, "%d fan tachometer inputs\n", ctx->tach_count);
567
568 if (ctx->tach_count) {
569 channel_count++; /* We also have a FAN channel. */
570
571 ctx->tachs = devm_kcalloc(dev, ctx->tach_count,
572 sizeof(struct pwm_fan_tach),
573 GFP_KERNEL);
574 if (!ctx->tachs)
575 return -ENOMEM;
576
577 ctx->fan_channel.type = hwmon_fan;
578 fan_channel_config = devm_kcalloc(dev, ctx->tach_count + 1,
579 sizeof(u32), GFP_KERNEL);
580 if (!fan_channel_config)
581 return -ENOMEM;
582 ctx->fan_channel.config = fan_channel_config;
583
584 ctx->pulses_per_revolution = devm_kmalloc_array(dev,
585 ctx->tach_count,
586 sizeof(*ctx->pulses_per_revolution),
587 GFP_KERNEL);
588 if (!ctx->pulses_per_revolution)
589 return -ENOMEM;
590
591 /* Setup default pulses per revolution */
592 for (i = 0; i < ctx->tach_count; i++)
593 ctx->pulses_per_revolution[i] = 2;
594
595 device_property_read_u32_array(dev, "pulses-per-revolution",
596 ctx->pulses_per_revolution, ctx->tach_count);
597 }
598
599 channels = devm_kcalloc(dev, channel_count + 1,
600 sizeof(struct hwmon_channel_info *), GFP_KERNEL);
601 if (!channels)
602 return -ENOMEM;
603
604 channels[0] = HWMON_CHANNEL_INFO(pwm, HWMON_PWM_INPUT | HWMON_PWM_ENABLE);
605
606 for (i = 0; i < ctx->tach_count; i++) {
607 struct pwm_fan_tach *tach = &ctx->tachs[i];
608
609 tach->irq = platform_get_irq(pdev, i);
610 if (tach->irq == -EPROBE_DEFER)
611 return tach->irq;
612 if (tach->irq > 0) {
613 ret = devm_request_irq(dev, tach->irq, pulse_handler, 0,
614 pdev->name, tach);
615 if (ret) {
616 dev_err(dev,
617 "Failed to request interrupt: %d\n",
618 ret);
619 return ret;
620 }
621 }
622
623 if (!ctx->pulses_per_revolution[i]) {
624 dev_err(dev, "pulses-per-revolution can't be zero.\n");
625 return -EINVAL;
626 }
627
628 fan_channel_config[i] = HWMON_F_INPUT;
629
630 dev_dbg(dev, "tach%d: irq=%d, pulses_per_revolution=%d\n",
631 i, tach->irq, ctx->pulses_per_revolution[i]);
632 }
633
634 if (ctx->tach_count > 0) {
635 ctx->sample_start = ktime_get();
636 mod_timer(&ctx->rpm_timer, jiffies + HZ);
637
638 channels[1] = &ctx->fan_channel;
639 }
640
641 ret = of_property_read_u32(dev->of_node, "fan-stop-to-start-percent",
642 &pwm_min_from_stopped);
643 if (!ret && pwm_min_from_stopped) {
644 ctx->pwm_duty_cycle_from_stopped =
645 DIV_ROUND_UP_ULL(pwm_min_from_stopped *
646 (ctx->pwm_state.period - 1),
647 100);
648 }
649 ret = of_property_read_u32(dev->of_node, "fan-stop-to-start-us",
650 &ctx->pwm_usec_from_stopped);
651 if (ret)
652 ctx->pwm_usec_from_stopped = 250000;
653
654 ctx->info.ops = &pwm_fan_hwmon_ops;
655 ctx->info.info = channels;
656
657 hwmon = devm_hwmon_device_register_with_info(dev, "pwmfan",
658 ctx, &ctx->info, NULL);
659 if (IS_ERR(hwmon)) {
660 dev_err(dev, "Failed to register hwmon device\n");
661 return PTR_ERR(hwmon);
662 }
663
664 ret = pwm_fan_get_cooling_data(dev, ctx);
665 if (ret)
666 return ret;
667
668 ctx->pwm_fan_state = ctx->pwm_fan_max_state;
669 if (IS_ENABLED(CONFIG_THERMAL)) {
670 cdev = devm_thermal_of_cooling_device_register(dev,
671 dev->of_node, "pwm-fan", ctx, &pwm_fan_cooling_ops);
672 if (IS_ERR(cdev)) {
673 ret = PTR_ERR(cdev);
674 dev_err(dev,
675 "Failed to register pwm-fan as cooling device: %d\n",
676 ret);
677 return ret;
678 }
679 ctx->cdev = cdev;
680 }
681
682 return 0;
683}
684
685static void pwm_fan_shutdown(struct platform_device *pdev)
686{
687 struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev);
688
689 pwm_fan_cleanup(ctx);
690}
691
692static int pwm_fan_suspend(struct device *dev)
693{
694 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
695
696 return pwm_fan_power_off(ctx, true);
697}
698
699static int pwm_fan_resume(struct device *dev)
700{
701 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
702
703 return set_pwm(ctx, ctx->pwm_value);
704}
705
706static DEFINE_SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume);
707
708static const struct of_device_id of_pwm_fan_match[] = {
709 { .compatible = "pwm-fan", },
710 {},
711};
712MODULE_DEVICE_TABLE(of, of_pwm_fan_match);
713
714static struct platform_driver pwm_fan_driver = {
715 .probe = pwm_fan_probe,
716 .shutdown = pwm_fan_shutdown,
717 .driver = {
718 .name = "pwm-fan",
719 .pm = pm_sleep_ptr(&pwm_fan_pm),
720 .of_match_table = of_pwm_fan_match,
721 },
722};
723
724module_platform_driver(pwm_fan_driver);
725
726MODULE_AUTHOR("Kamil Debski <k.debski@samsung.com>");
727MODULE_ALIAS("platform:pwm-fan");
728MODULE_DESCRIPTION("PWM FAN driver");
729MODULE_LICENSE("GPL");
1/*
2 * pwm-fan.c - Hwmon driver for fans connected to PWM lines.
3 *
4 * Copyright (c) 2014 Samsung Electronics Co., Ltd.
5 *
6 * Author: Kamil Debski <k.debski@samsung.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 */
18
19#include <linux/hwmon.h>
20#include <linux/hwmon-sysfs.h>
21#include <linux/module.h>
22#include <linux/mutex.h>
23#include <linux/of.h>
24#include <linux/platform_device.h>
25#include <linux/pwm.h>
26#include <linux/sysfs.h>
27#include <linux/thermal.h>
28
29#define MAX_PWM 255
30
31struct pwm_fan_ctx {
32 struct mutex lock;
33 struct pwm_device *pwm;
34 unsigned int pwm_value;
35 unsigned int pwm_fan_state;
36 unsigned int pwm_fan_max_state;
37 unsigned int *pwm_fan_cooling_levels;
38 struct thermal_cooling_device *cdev;
39};
40
41static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
42{
43 struct pwm_args pargs;
44 unsigned long duty;
45 int ret = 0;
46
47 pwm_get_args(ctx->pwm, &pargs);
48
49 mutex_lock(&ctx->lock);
50 if (ctx->pwm_value == pwm)
51 goto exit_set_pwm_err;
52
53 duty = DIV_ROUND_UP(pwm * (pargs.period - 1), MAX_PWM);
54 ret = pwm_config(ctx->pwm, duty, pargs.period);
55 if (ret)
56 goto exit_set_pwm_err;
57
58 if (pwm == 0)
59 pwm_disable(ctx->pwm);
60
61 if (ctx->pwm_value == 0) {
62 ret = pwm_enable(ctx->pwm);
63 if (ret)
64 goto exit_set_pwm_err;
65 }
66
67 ctx->pwm_value = pwm;
68exit_set_pwm_err:
69 mutex_unlock(&ctx->lock);
70 return ret;
71}
72
73static void pwm_fan_update_state(struct pwm_fan_ctx *ctx, unsigned long pwm)
74{
75 int i;
76
77 for (i = 0; i < ctx->pwm_fan_max_state; ++i)
78 if (pwm < ctx->pwm_fan_cooling_levels[i + 1])
79 break;
80
81 ctx->pwm_fan_state = i;
82}
83
84static ssize_t set_pwm(struct device *dev, struct device_attribute *attr,
85 const char *buf, size_t count)
86{
87 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
88 unsigned long pwm;
89 int ret;
90
91 if (kstrtoul(buf, 10, &pwm) || pwm > MAX_PWM)
92 return -EINVAL;
93
94 ret = __set_pwm(ctx, pwm);
95 if (ret)
96 return ret;
97
98 pwm_fan_update_state(ctx, pwm);
99 return count;
100}
101
102static ssize_t show_pwm(struct device *dev,
103 struct device_attribute *attr, char *buf)
104{
105 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
106
107 return sprintf(buf, "%u\n", ctx->pwm_value);
108}
109
110
111static SENSOR_DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm, set_pwm, 0);
112
113static struct attribute *pwm_fan_attrs[] = {
114 &sensor_dev_attr_pwm1.dev_attr.attr,
115 NULL,
116};
117
118ATTRIBUTE_GROUPS(pwm_fan);
119
120/* thermal cooling device callbacks */
121static int pwm_fan_get_max_state(struct thermal_cooling_device *cdev,
122 unsigned long *state)
123{
124 struct pwm_fan_ctx *ctx = cdev->devdata;
125
126 if (!ctx)
127 return -EINVAL;
128
129 *state = ctx->pwm_fan_max_state;
130
131 return 0;
132}
133
134static int pwm_fan_get_cur_state(struct thermal_cooling_device *cdev,
135 unsigned long *state)
136{
137 struct pwm_fan_ctx *ctx = cdev->devdata;
138
139 if (!ctx)
140 return -EINVAL;
141
142 *state = ctx->pwm_fan_state;
143
144 return 0;
145}
146
147static int
148pwm_fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)
149{
150 struct pwm_fan_ctx *ctx = cdev->devdata;
151 int ret;
152
153 if (!ctx || (state > ctx->pwm_fan_max_state))
154 return -EINVAL;
155
156 if (state == ctx->pwm_fan_state)
157 return 0;
158
159 ret = __set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]);
160 if (ret) {
161 dev_err(&cdev->device, "Cannot set pwm!\n");
162 return ret;
163 }
164
165 ctx->pwm_fan_state = state;
166
167 return ret;
168}
169
170static const struct thermal_cooling_device_ops pwm_fan_cooling_ops = {
171 .get_max_state = pwm_fan_get_max_state,
172 .get_cur_state = pwm_fan_get_cur_state,
173 .set_cur_state = pwm_fan_set_cur_state,
174};
175
176static int pwm_fan_of_get_cooling_data(struct device *dev,
177 struct pwm_fan_ctx *ctx)
178{
179 struct device_node *np = dev->of_node;
180 int num, i, ret;
181
182 if (!of_find_property(np, "cooling-levels", NULL))
183 return 0;
184
185 ret = of_property_count_u32_elems(np, "cooling-levels");
186 if (ret <= 0) {
187 dev_err(dev, "Wrong data!\n");
188 return ret ? : -EINVAL;
189 }
190
191 num = ret;
192 ctx->pwm_fan_cooling_levels = devm_kzalloc(dev, num * sizeof(u32),
193 GFP_KERNEL);
194 if (!ctx->pwm_fan_cooling_levels)
195 return -ENOMEM;
196
197 ret = of_property_read_u32_array(np, "cooling-levels",
198 ctx->pwm_fan_cooling_levels, num);
199 if (ret) {
200 dev_err(dev, "Property 'cooling-levels' cannot be read!\n");
201 return ret;
202 }
203
204 for (i = 0; i < num; i++) {
205 if (ctx->pwm_fan_cooling_levels[i] > MAX_PWM) {
206 dev_err(dev, "PWM fan state[%d]:%d > %d\n", i,
207 ctx->pwm_fan_cooling_levels[i], MAX_PWM);
208 return -EINVAL;
209 }
210 }
211
212 ctx->pwm_fan_max_state = num - 1;
213
214 return 0;
215}
216
217static int pwm_fan_probe(struct platform_device *pdev)
218{
219 struct thermal_cooling_device *cdev;
220 struct pwm_fan_ctx *ctx;
221 struct pwm_args pargs;
222 struct device *hwmon;
223 int duty_cycle;
224 int ret;
225
226 ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
227 if (!ctx)
228 return -ENOMEM;
229
230 mutex_init(&ctx->lock);
231
232 ctx->pwm = devm_of_pwm_get(&pdev->dev, pdev->dev.of_node, NULL);
233 if (IS_ERR(ctx->pwm)) {
234 dev_err(&pdev->dev, "Could not get PWM\n");
235 return PTR_ERR(ctx->pwm);
236 }
237
238 platform_set_drvdata(pdev, ctx);
239
240 /*
241 * FIXME: pwm_apply_args() should be removed when switching to the
242 * atomic PWM API.
243 */
244 pwm_apply_args(ctx->pwm);
245
246 /* Set duty cycle to maximum allowed */
247 pwm_get_args(ctx->pwm, &pargs);
248
249 duty_cycle = pargs.period - 1;
250 ctx->pwm_value = MAX_PWM;
251
252 ret = pwm_config(ctx->pwm, duty_cycle, pargs.period);
253 if (ret) {
254 dev_err(&pdev->dev, "Failed to configure PWM\n");
255 return ret;
256 }
257
258 /* Enbale PWM output */
259 ret = pwm_enable(ctx->pwm);
260 if (ret) {
261 dev_err(&pdev->dev, "Failed to enable PWM\n");
262 return ret;
263 }
264
265 hwmon = devm_hwmon_device_register_with_groups(&pdev->dev, "pwmfan",
266 ctx, pwm_fan_groups);
267 if (IS_ERR(hwmon)) {
268 dev_err(&pdev->dev, "Failed to register hwmon device\n");
269 pwm_disable(ctx->pwm);
270 return PTR_ERR(hwmon);
271 }
272
273 ret = pwm_fan_of_get_cooling_data(&pdev->dev, ctx);
274 if (ret)
275 return ret;
276
277 ctx->pwm_fan_state = ctx->pwm_fan_max_state;
278 if (IS_ENABLED(CONFIG_THERMAL)) {
279 cdev = thermal_of_cooling_device_register(pdev->dev.of_node,
280 "pwm-fan", ctx,
281 &pwm_fan_cooling_ops);
282 if (IS_ERR(cdev)) {
283 dev_err(&pdev->dev,
284 "Failed to register pwm-fan as cooling device");
285 pwm_disable(ctx->pwm);
286 return PTR_ERR(cdev);
287 }
288 ctx->cdev = cdev;
289 thermal_cdev_update(cdev);
290 }
291
292 return 0;
293}
294
295static int pwm_fan_remove(struct platform_device *pdev)
296{
297 struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev);
298
299 thermal_cooling_device_unregister(ctx->cdev);
300 if (ctx->pwm_value)
301 pwm_disable(ctx->pwm);
302 return 0;
303}
304
305#ifdef CONFIG_PM_SLEEP
306static int pwm_fan_suspend(struct device *dev)
307{
308 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
309
310 if (ctx->pwm_value)
311 pwm_disable(ctx->pwm);
312 return 0;
313}
314
315static int pwm_fan_resume(struct device *dev)
316{
317 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
318 struct pwm_args pargs;
319 unsigned long duty;
320 int ret;
321
322 if (ctx->pwm_value == 0)
323 return 0;
324
325 pwm_get_args(ctx->pwm, &pargs);
326 duty = DIV_ROUND_UP(ctx->pwm_value * (pargs.period - 1), MAX_PWM);
327 ret = pwm_config(ctx->pwm, duty, pargs.period);
328 if (ret)
329 return ret;
330 return pwm_enable(ctx->pwm);
331}
332#endif
333
334static SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume);
335
336static const struct of_device_id of_pwm_fan_match[] = {
337 { .compatible = "pwm-fan", },
338 {},
339};
340MODULE_DEVICE_TABLE(of, of_pwm_fan_match);
341
342static struct platform_driver pwm_fan_driver = {
343 .probe = pwm_fan_probe,
344 .remove = pwm_fan_remove,
345 .driver = {
346 .name = "pwm-fan",
347 .pm = &pwm_fan_pm,
348 .of_match_table = of_pwm_fan_match,
349 },
350};
351
352module_platform_driver(pwm_fan_driver);
353
354MODULE_AUTHOR("Kamil Debski <k.debski@samsung.com>");
355MODULE_ALIAS("platform:pwm-fan");
356MODULE_DESCRIPTION("PWM FAN driver");
357MODULE_LICENSE("GPL");