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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// 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/hwmon.h>
11#include <linux/interrupt.h>
12#include <linux/module.h>
13#include <linux/mutex.h>
14#include <linux/of.h>
15#include <linux/platform_device.h>
16#include <linux/pwm.h>
17#include <linux/regulator/consumer.h>
18#include <linux/sysfs.h>
19#include <linux/thermal.h>
20#include <linux/timer.h>
21
22#define MAX_PWM 255
23
24struct pwm_fan_tach {
25 int irq;
26 atomic_t pulses;
27 unsigned int rpm;
28 u8 pulses_per_revolution;
29};
30
31struct pwm_fan_ctx {
32 struct mutex lock;
33 struct pwm_device *pwm;
34 struct pwm_state pwm_state;
35 struct regulator *reg_en;
36
37 int tach_count;
38 struct pwm_fan_tach *tachs;
39 ktime_t sample_start;
40 struct timer_list rpm_timer;
41
42 unsigned int pwm_value;
43 unsigned int pwm_fan_state;
44 unsigned int pwm_fan_max_state;
45 unsigned int *pwm_fan_cooling_levels;
46 struct thermal_cooling_device *cdev;
47
48 struct hwmon_chip_info info;
49 struct hwmon_channel_info fan_channel;
50};
51
52static const u32 pwm_fan_channel_config_pwm[] = {
53 HWMON_PWM_INPUT,
54 0
55};
56
57static const struct hwmon_channel_info pwm_fan_channel_pwm = {
58 .type = hwmon_pwm,
59 .config = pwm_fan_channel_config_pwm,
60};
61
62/* This handler assumes self resetting edge triggered interrupt. */
63static irqreturn_t pulse_handler(int irq, void *dev_id)
64{
65 struct pwm_fan_tach *tach = dev_id;
66
67 atomic_inc(&tach->pulses);
68
69 return IRQ_HANDLED;
70}
71
72static void sample_timer(struct timer_list *t)
73{
74 struct pwm_fan_ctx *ctx = from_timer(ctx, t, rpm_timer);
75 unsigned int delta = ktime_ms_delta(ktime_get(), ctx->sample_start);
76 int i;
77
78 if (delta) {
79 for (i = 0; i < ctx->tach_count; i++) {
80 struct pwm_fan_tach *tach = &ctx->tachs[i];
81 int pulses;
82
83 pulses = atomic_read(&tach->pulses);
84 atomic_sub(pulses, &tach->pulses);
85 tach->rpm = (unsigned int)(pulses * 1000 * 60) /
86 (tach->pulses_per_revolution * delta);
87 }
88
89 ctx->sample_start = ktime_get();
90 }
91
92 mod_timer(&ctx->rpm_timer, jiffies + HZ);
93}
94
95static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
96{
97 unsigned long period;
98 int ret = 0;
99 struct pwm_state *state = &ctx->pwm_state;
100
101 mutex_lock(&ctx->lock);
102 if (ctx->pwm_value == pwm)
103 goto exit_set_pwm_err;
104
105 period = state->period;
106 state->duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM);
107 state->enabled = pwm ? true : false;
108
109 ret = pwm_apply_state(ctx->pwm, state);
110 if (!ret)
111 ctx->pwm_value = pwm;
112exit_set_pwm_err:
113 mutex_unlock(&ctx->lock);
114 return ret;
115}
116
117static void pwm_fan_update_state(struct pwm_fan_ctx *ctx, unsigned long pwm)
118{
119 int i;
120
121 for (i = 0; i < ctx->pwm_fan_max_state; ++i)
122 if (pwm < ctx->pwm_fan_cooling_levels[i + 1])
123 break;
124
125 ctx->pwm_fan_state = i;
126}
127
128static int pwm_fan_write(struct device *dev, enum hwmon_sensor_types type,
129 u32 attr, int channel, long val)
130{
131 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
132 int ret;
133
134 if (val < 0 || val > MAX_PWM)
135 return -EINVAL;
136
137 ret = __set_pwm(ctx, val);
138 if (ret)
139 return ret;
140
141 pwm_fan_update_state(ctx, val);
142 return 0;
143}
144
145static int pwm_fan_read(struct device *dev, enum hwmon_sensor_types type,
146 u32 attr, int channel, long *val)
147{
148 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
149
150 switch (type) {
151 case hwmon_pwm:
152 *val = ctx->pwm_value;
153 return 0;
154
155 case hwmon_fan:
156 *val = ctx->tachs[channel].rpm;
157 return 0;
158
159 default:
160 return -ENOTSUPP;
161 }
162}
163
164static umode_t pwm_fan_is_visible(const void *data,
165 enum hwmon_sensor_types type,
166 u32 attr, int channel)
167{
168 switch (type) {
169 case hwmon_pwm:
170 return 0644;
171
172 case hwmon_fan:
173 return 0444;
174
175 default:
176 return 0;
177 }
178}
179
180static const struct hwmon_ops pwm_fan_hwmon_ops = {
181 .is_visible = pwm_fan_is_visible,
182 .read = pwm_fan_read,
183 .write = pwm_fan_write,
184};
185
186/* thermal cooling device callbacks */
187static int pwm_fan_get_max_state(struct thermal_cooling_device *cdev,
188 unsigned long *state)
189{
190 struct pwm_fan_ctx *ctx = cdev->devdata;
191
192 if (!ctx)
193 return -EINVAL;
194
195 *state = ctx->pwm_fan_max_state;
196
197 return 0;
198}
199
200static int pwm_fan_get_cur_state(struct thermal_cooling_device *cdev,
201 unsigned long *state)
202{
203 struct pwm_fan_ctx *ctx = cdev->devdata;
204
205 if (!ctx)
206 return -EINVAL;
207
208 *state = ctx->pwm_fan_state;
209
210 return 0;
211}
212
213static int
214pwm_fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)
215{
216 struct pwm_fan_ctx *ctx = cdev->devdata;
217 int ret;
218
219 if (!ctx || (state > ctx->pwm_fan_max_state))
220 return -EINVAL;
221
222 if (state == ctx->pwm_fan_state)
223 return 0;
224
225 ret = __set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]);
226 if (ret) {
227 dev_err(&cdev->device, "Cannot set pwm!\n");
228 return ret;
229 }
230
231 ctx->pwm_fan_state = state;
232
233 return ret;
234}
235
236static const struct thermal_cooling_device_ops pwm_fan_cooling_ops = {
237 .get_max_state = pwm_fan_get_max_state,
238 .get_cur_state = pwm_fan_get_cur_state,
239 .set_cur_state = pwm_fan_set_cur_state,
240};
241
242static int pwm_fan_of_get_cooling_data(struct device *dev,
243 struct pwm_fan_ctx *ctx)
244{
245 struct device_node *np = dev->of_node;
246 int num, i, ret;
247
248 if (!of_find_property(np, "cooling-levels", NULL))
249 return 0;
250
251 ret = of_property_count_u32_elems(np, "cooling-levels");
252 if (ret <= 0) {
253 dev_err(dev, "Wrong data!\n");
254 return ret ? : -EINVAL;
255 }
256
257 num = ret;
258 ctx->pwm_fan_cooling_levels = devm_kcalloc(dev, num, sizeof(u32),
259 GFP_KERNEL);
260 if (!ctx->pwm_fan_cooling_levels)
261 return -ENOMEM;
262
263 ret = of_property_read_u32_array(np, "cooling-levels",
264 ctx->pwm_fan_cooling_levels, num);
265 if (ret) {
266 dev_err(dev, "Property 'cooling-levels' cannot be read!\n");
267 return ret;
268 }
269
270 for (i = 0; i < num; i++) {
271 if (ctx->pwm_fan_cooling_levels[i] > MAX_PWM) {
272 dev_err(dev, "PWM fan state[%d]:%d > %d\n", i,
273 ctx->pwm_fan_cooling_levels[i], MAX_PWM);
274 return -EINVAL;
275 }
276 }
277
278 ctx->pwm_fan_max_state = num - 1;
279
280 return 0;
281}
282
283static void pwm_fan_regulator_disable(void *data)
284{
285 regulator_disable(data);
286}
287
288static void pwm_fan_pwm_disable(void *__ctx)
289{
290 struct pwm_fan_ctx *ctx = __ctx;
291
292 ctx->pwm_state.enabled = false;
293 pwm_apply_state(ctx->pwm, &ctx->pwm_state);
294 del_timer_sync(&ctx->rpm_timer);
295}
296
297static int pwm_fan_probe(struct platform_device *pdev)
298{
299 struct thermal_cooling_device *cdev;
300 struct device *dev = &pdev->dev;
301 struct pwm_fan_ctx *ctx;
302 struct device *hwmon;
303 int ret;
304 const struct hwmon_channel_info **channels;
305 u32 *fan_channel_config;
306 int channel_count = 1; /* We always have a PWM channel. */
307 int i;
308
309 ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
310 if (!ctx)
311 return -ENOMEM;
312
313 mutex_init(&ctx->lock);
314
315 ctx->pwm = devm_of_pwm_get(dev, dev->of_node, NULL);
316 if (IS_ERR(ctx->pwm))
317 return dev_err_probe(dev, PTR_ERR(ctx->pwm), "Could not get PWM\n");
318
319 platform_set_drvdata(pdev, ctx);
320
321 ctx->reg_en = devm_regulator_get_optional(dev, "fan");
322 if (IS_ERR(ctx->reg_en)) {
323 if (PTR_ERR(ctx->reg_en) != -ENODEV)
324 return PTR_ERR(ctx->reg_en);
325
326 ctx->reg_en = NULL;
327 } else {
328 ret = regulator_enable(ctx->reg_en);
329 if (ret) {
330 dev_err(dev, "Failed to enable fan supply: %d\n", ret);
331 return ret;
332 }
333 ret = devm_add_action_or_reset(dev, pwm_fan_regulator_disable,
334 ctx->reg_en);
335 if (ret)
336 return ret;
337 }
338
339 ctx->pwm_value = MAX_PWM;
340
341 pwm_init_state(ctx->pwm, &ctx->pwm_state);
342
343 /*
344 * __set_pwm assumes that MAX_PWM * (period - 1) fits into an unsigned
345 * long. Check this here to prevent the fan running at a too low
346 * frequency.
347 */
348 if (ctx->pwm_state.period > ULONG_MAX / MAX_PWM + 1) {
349 dev_err(dev, "Configured period too big\n");
350 return -EINVAL;
351 }
352
353 /* Set duty cycle to maximum allowed and enable PWM output */
354 ret = __set_pwm(ctx, MAX_PWM);
355 if (ret) {
356 dev_err(dev, "Failed to configure PWM: %d\n", ret);
357 return ret;
358 }
359 timer_setup(&ctx->rpm_timer, sample_timer, 0);
360 ret = devm_add_action_or_reset(dev, pwm_fan_pwm_disable, ctx);
361 if (ret)
362 return ret;
363
364 ctx->tach_count = platform_irq_count(pdev);
365 if (ctx->tach_count < 0)
366 return dev_err_probe(dev, ctx->tach_count,
367 "Could not get number of fan tachometer inputs\n");
368 dev_dbg(dev, "%d fan tachometer inputs\n", ctx->tach_count);
369
370 if (ctx->tach_count) {
371 channel_count++; /* We also have a FAN channel. */
372
373 ctx->tachs = devm_kcalloc(dev, ctx->tach_count,
374 sizeof(struct pwm_fan_tach),
375 GFP_KERNEL);
376 if (!ctx->tachs)
377 return -ENOMEM;
378
379 ctx->fan_channel.type = hwmon_fan;
380 fan_channel_config = devm_kcalloc(dev, ctx->tach_count + 1,
381 sizeof(u32), GFP_KERNEL);
382 if (!fan_channel_config)
383 return -ENOMEM;
384 ctx->fan_channel.config = fan_channel_config;
385 }
386
387 channels = devm_kcalloc(dev, channel_count + 1,
388 sizeof(struct hwmon_channel_info *), GFP_KERNEL);
389 if (!channels)
390 return -ENOMEM;
391
392 channels[0] = &pwm_fan_channel_pwm;
393
394 for (i = 0; i < ctx->tach_count; i++) {
395 struct pwm_fan_tach *tach = &ctx->tachs[i];
396 u32 ppr = 2;
397
398 tach->irq = platform_get_irq(pdev, i);
399 if (tach->irq == -EPROBE_DEFER)
400 return tach->irq;
401 if (tach->irq > 0) {
402 ret = devm_request_irq(dev, tach->irq, pulse_handler, 0,
403 pdev->name, tach);
404 if (ret) {
405 dev_err(dev,
406 "Failed to request interrupt: %d\n",
407 ret);
408 return ret;
409 }
410 }
411
412 of_property_read_u32_index(dev->of_node,
413 "pulses-per-revolution",
414 i,
415 &ppr);
416 tach->pulses_per_revolution = ppr;
417 if (!tach->pulses_per_revolution) {
418 dev_err(dev, "pulses-per-revolution can't be zero.\n");
419 return -EINVAL;
420 }
421
422 fan_channel_config[i] = HWMON_F_INPUT;
423
424 dev_dbg(dev, "tach%d: irq=%d, pulses_per_revolution=%d\n",
425 i, tach->irq, tach->pulses_per_revolution);
426 }
427
428 if (ctx->tach_count > 0) {
429 ctx->sample_start = ktime_get();
430 mod_timer(&ctx->rpm_timer, jiffies + HZ);
431
432 channels[1] = &ctx->fan_channel;
433 }
434
435 ctx->info.ops = &pwm_fan_hwmon_ops;
436 ctx->info.info = channels;
437
438 hwmon = devm_hwmon_device_register_with_info(dev, "pwmfan",
439 ctx, &ctx->info, NULL);
440 if (IS_ERR(hwmon)) {
441 dev_err(dev, "Failed to register hwmon device\n");
442 return PTR_ERR(hwmon);
443 }
444
445 ret = pwm_fan_of_get_cooling_data(dev, ctx);
446 if (ret)
447 return ret;
448
449 ctx->pwm_fan_state = ctx->pwm_fan_max_state;
450 if (IS_ENABLED(CONFIG_THERMAL)) {
451 cdev = devm_thermal_of_cooling_device_register(dev,
452 dev->of_node, "pwm-fan", ctx, &pwm_fan_cooling_ops);
453 if (IS_ERR(cdev)) {
454 ret = PTR_ERR(cdev);
455 dev_err(dev,
456 "Failed to register pwm-fan as cooling device: %d\n",
457 ret);
458 return ret;
459 }
460 ctx->cdev = cdev;
461 }
462
463 return 0;
464}
465
466static int pwm_fan_disable(struct device *dev)
467{
468 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
469 int ret;
470
471 if (ctx->pwm_value) {
472 /* keep ctx->pwm_state unmodified for pwm_fan_resume() */
473 struct pwm_state state = ctx->pwm_state;
474
475 state.duty_cycle = 0;
476 state.enabled = false;
477 ret = pwm_apply_state(ctx->pwm, &state);
478 if (ret < 0)
479 return ret;
480 }
481
482 if (ctx->reg_en) {
483 ret = regulator_disable(ctx->reg_en);
484 if (ret) {
485 dev_err(dev, "Failed to disable fan supply: %d\n", ret);
486 return ret;
487 }
488 }
489
490 return 0;
491}
492
493static void pwm_fan_shutdown(struct platform_device *pdev)
494{
495 pwm_fan_disable(&pdev->dev);
496}
497
498#ifdef CONFIG_PM_SLEEP
499static int pwm_fan_suspend(struct device *dev)
500{
501 return pwm_fan_disable(dev);
502}
503
504static int pwm_fan_resume(struct device *dev)
505{
506 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
507 int ret;
508
509 if (ctx->reg_en) {
510 ret = regulator_enable(ctx->reg_en);
511 if (ret) {
512 dev_err(dev, "Failed to enable fan supply: %d\n", ret);
513 return ret;
514 }
515 }
516
517 if (ctx->pwm_value == 0)
518 return 0;
519
520 return pwm_apply_state(ctx->pwm, &ctx->pwm_state);
521}
522#endif
523
524static SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume);
525
526static const struct of_device_id of_pwm_fan_match[] = {
527 { .compatible = "pwm-fan", },
528 {},
529};
530MODULE_DEVICE_TABLE(of, of_pwm_fan_match);
531
532static struct platform_driver pwm_fan_driver = {
533 .probe = pwm_fan_probe,
534 .shutdown = pwm_fan_shutdown,
535 .driver = {
536 .name = "pwm-fan",
537 .pm = &pwm_fan_pm,
538 .of_match_table = of_pwm_fan_match,
539 },
540};
541
542module_platform_driver(pwm_fan_driver);
543
544MODULE_AUTHOR("Kamil Debski <k.debski@samsung.com>");
545MODULE_ALIAS("platform:pwm-fan");
546MODULE_DESCRIPTION("PWM FAN driver");
547MODULE_LICENSE("GPL");