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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/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
31enum pwm_fan_enable_mode {
32 pwm_off_reg_off,
33 pwm_disable_reg_enable,
34 pwm_enable_reg_enable,
35 pwm_disable_reg_disable,
36};
37
38struct pwm_fan_ctx {
39 struct device *dev;
40
41 struct mutex lock;
42 struct pwm_device *pwm;
43 struct pwm_state pwm_state;
44 struct regulator *reg_en;
45 enum pwm_fan_enable_mode enable_mode;
46 bool regulator_enabled;
47 bool enabled;
48
49 int tach_count;
50 struct pwm_fan_tach *tachs;
51 ktime_t sample_start;
52 struct timer_list rpm_timer;
53
54 unsigned int pwm_value;
55 unsigned int pwm_fan_state;
56 unsigned int pwm_fan_max_state;
57 unsigned int *pwm_fan_cooling_levels;
58 struct thermal_cooling_device *cdev;
59
60 struct hwmon_chip_info info;
61 struct hwmon_channel_info fan_channel;
62};
63
64/* This handler assumes self resetting edge triggered interrupt. */
65static irqreturn_t pulse_handler(int irq, void *dev_id)
66{
67 struct pwm_fan_tach *tach = dev_id;
68
69 atomic_inc(&tach->pulses);
70
71 return IRQ_HANDLED;
72}
73
74static void sample_timer(struct timer_list *t)
75{
76 struct pwm_fan_ctx *ctx = from_timer(ctx, t, rpm_timer);
77 unsigned int delta = ktime_ms_delta(ktime_get(), ctx->sample_start);
78 int i;
79
80 if (delta) {
81 for (i = 0; i < ctx->tach_count; i++) {
82 struct pwm_fan_tach *tach = &ctx->tachs[i];
83 int pulses;
84
85 pulses = atomic_read(&tach->pulses);
86 atomic_sub(pulses, &tach->pulses);
87 tach->rpm = (unsigned int)(pulses * 1000 * 60) /
88 (tach->pulses_per_revolution * delta);
89 }
90
91 ctx->sample_start = ktime_get();
92 }
93
94 mod_timer(&ctx->rpm_timer, jiffies + HZ);
95}
96
97static void pwm_fan_enable_mode_2_state(int enable_mode,
98 struct pwm_state *state,
99 bool *enable_regulator)
100{
101 switch (enable_mode) {
102 case pwm_disable_reg_enable:
103 /* disable pwm, keep regulator enabled */
104 state->enabled = false;
105 *enable_regulator = true;
106 break;
107 case pwm_enable_reg_enable:
108 /* keep pwm and regulator enabled */
109 state->enabled = true;
110 *enable_regulator = true;
111 break;
112 case pwm_off_reg_off:
113 case pwm_disable_reg_disable:
114 /* disable pwm and regulator */
115 state->enabled = false;
116 *enable_regulator = false;
117 }
118}
119
120static int pwm_fan_switch_power(struct pwm_fan_ctx *ctx, bool on)
121{
122 int ret = 0;
123
124 if (!ctx->reg_en)
125 return ret;
126
127 if (!ctx->regulator_enabled && on) {
128 ret = regulator_enable(ctx->reg_en);
129 if (ret == 0)
130 ctx->regulator_enabled = true;
131 } else if (ctx->regulator_enabled && !on) {
132 ret = regulator_disable(ctx->reg_en);
133 if (ret == 0)
134 ctx->regulator_enabled = false;
135 }
136 return ret;
137}
138
139static int pwm_fan_power_on(struct pwm_fan_ctx *ctx)
140{
141 struct pwm_state *state = &ctx->pwm_state;
142 int ret;
143
144 if (ctx->enabled)
145 return 0;
146
147 ret = pwm_fan_switch_power(ctx, true);
148 if (ret < 0) {
149 dev_err(ctx->dev, "failed to enable power supply\n");
150 return ret;
151 }
152
153 state->enabled = true;
154 ret = pwm_apply_might_sleep(ctx->pwm, state);
155 if (ret) {
156 dev_err(ctx->dev, "failed to enable PWM\n");
157 goto disable_regulator;
158 }
159
160 ctx->enabled = true;
161
162 return 0;
163
164disable_regulator:
165 pwm_fan_switch_power(ctx, false);
166 return ret;
167}
168
169static int pwm_fan_power_off(struct pwm_fan_ctx *ctx)
170{
171 struct pwm_state *state = &ctx->pwm_state;
172 bool enable_regulator = false;
173 int ret;
174
175 if (!ctx->enabled)
176 return 0;
177
178 pwm_fan_enable_mode_2_state(ctx->enable_mode,
179 state,
180 &enable_regulator);
181
182 state->enabled = false;
183 state->duty_cycle = 0;
184 ret = pwm_apply_might_sleep(ctx->pwm, state);
185 if (ret) {
186 dev_err(ctx->dev, "failed to disable PWM\n");
187 return ret;
188 }
189
190 pwm_fan_switch_power(ctx, enable_regulator);
191
192 ctx->enabled = false;
193
194 return 0;
195}
196
197static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
198{
199 struct pwm_state *state = &ctx->pwm_state;
200 unsigned long period;
201 int ret = 0;
202
203 if (pwm > 0) {
204 if (ctx->enable_mode == pwm_off_reg_off)
205 /* pwm-fan hard disabled */
206 return 0;
207
208 period = state->period;
209 state->duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM);
210 ret = pwm_apply_might_sleep(ctx->pwm, state);
211 if (ret)
212 return ret;
213 ret = pwm_fan_power_on(ctx);
214 } else {
215 ret = pwm_fan_power_off(ctx);
216 }
217 if (!ret)
218 ctx->pwm_value = pwm;
219
220 return ret;
221}
222
223static int set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
224{
225 int ret;
226
227 mutex_lock(&ctx->lock);
228 ret = __set_pwm(ctx, pwm);
229 mutex_unlock(&ctx->lock);
230
231 return ret;
232}
233
234static void pwm_fan_update_state(struct pwm_fan_ctx *ctx, unsigned long pwm)
235{
236 int i;
237
238 for (i = 0; i < ctx->pwm_fan_max_state; ++i)
239 if (pwm < ctx->pwm_fan_cooling_levels[i + 1])
240 break;
241
242 ctx->pwm_fan_state = i;
243}
244
245static int pwm_fan_update_enable(struct pwm_fan_ctx *ctx, long val)
246{
247 int ret = 0;
248 int old_val;
249
250 mutex_lock(&ctx->lock);
251
252 if (ctx->enable_mode == val)
253 goto out;
254
255 old_val = ctx->enable_mode;
256 ctx->enable_mode = val;
257
258 if (val == 0) {
259 /* Disable pwm-fan unconditionally */
260 if (ctx->enabled)
261 ret = __set_pwm(ctx, 0);
262 else
263 ret = pwm_fan_switch_power(ctx, false);
264 if (ret)
265 ctx->enable_mode = old_val;
266 pwm_fan_update_state(ctx, 0);
267 } else {
268 /*
269 * Change PWM and/or regulator state if currently disabled
270 * Nothing to do if currently enabled
271 */
272 if (!ctx->enabled) {
273 struct pwm_state *state = &ctx->pwm_state;
274 bool enable_regulator = false;
275
276 state->duty_cycle = 0;
277 pwm_fan_enable_mode_2_state(val,
278 state,
279 &enable_regulator);
280
281 pwm_apply_might_sleep(ctx->pwm, state);
282 pwm_fan_switch_power(ctx, enable_regulator);
283 pwm_fan_update_state(ctx, 0);
284 }
285 }
286out:
287 mutex_unlock(&ctx->lock);
288
289 return ret;
290}
291
292static int pwm_fan_write(struct device *dev, enum hwmon_sensor_types type,
293 u32 attr, int channel, long val)
294{
295 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
296 int ret;
297
298 switch (attr) {
299 case hwmon_pwm_input:
300 if (val < 0 || val > MAX_PWM)
301 return -EINVAL;
302 ret = set_pwm(ctx, val);
303 if (ret)
304 return ret;
305 pwm_fan_update_state(ctx, val);
306 break;
307 case hwmon_pwm_enable:
308 if (val < 0 || val > 3)
309 ret = -EINVAL;
310 else
311 ret = pwm_fan_update_enable(ctx, val);
312
313 return ret;
314 default:
315 return -EOPNOTSUPP;
316 }
317
318 return 0;
319}
320
321static int pwm_fan_read(struct device *dev, enum hwmon_sensor_types type,
322 u32 attr, int channel, long *val)
323{
324 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
325
326 switch (type) {
327 case hwmon_pwm:
328 switch (attr) {
329 case hwmon_pwm_input:
330 *val = ctx->pwm_value;
331 return 0;
332 case hwmon_pwm_enable:
333 *val = ctx->enable_mode;
334 return 0;
335 }
336 return -EOPNOTSUPP;
337 case hwmon_fan:
338 *val = ctx->tachs[channel].rpm;
339 return 0;
340
341 default:
342 return -ENOTSUPP;
343 }
344}
345
346static umode_t pwm_fan_is_visible(const void *data,
347 enum hwmon_sensor_types type,
348 u32 attr, int channel)
349{
350 switch (type) {
351 case hwmon_pwm:
352 return 0644;
353
354 case hwmon_fan:
355 return 0444;
356
357 default:
358 return 0;
359 }
360}
361
362static const struct hwmon_ops pwm_fan_hwmon_ops = {
363 .is_visible = pwm_fan_is_visible,
364 .read = pwm_fan_read,
365 .write = pwm_fan_write,
366};
367
368/* thermal cooling device callbacks */
369static int pwm_fan_get_max_state(struct thermal_cooling_device *cdev,
370 unsigned long *state)
371{
372 struct pwm_fan_ctx *ctx = cdev->devdata;
373
374 if (!ctx)
375 return -EINVAL;
376
377 *state = ctx->pwm_fan_max_state;
378
379 return 0;
380}
381
382static int pwm_fan_get_cur_state(struct thermal_cooling_device *cdev,
383 unsigned long *state)
384{
385 struct pwm_fan_ctx *ctx = cdev->devdata;
386
387 if (!ctx)
388 return -EINVAL;
389
390 *state = ctx->pwm_fan_state;
391
392 return 0;
393}
394
395static int
396pwm_fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)
397{
398 struct pwm_fan_ctx *ctx = cdev->devdata;
399 int ret;
400
401 if (!ctx || (state > ctx->pwm_fan_max_state))
402 return -EINVAL;
403
404 if (state == ctx->pwm_fan_state)
405 return 0;
406
407 ret = set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]);
408 if (ret) {
409 dev_err(&cdev->device, "Cannot set pwm!\n");
410 return ret;
411 }
412
413 ctx->pwm_fan_state = state;
414
415 return ret;
416}
417
418static const struct thermal_cooling_device_ops pwm_fan_cooling_ops = {
419 .get_max_state = pwm_fan_get_max_state,
420 .get_cur_state = pwm_fan_get_cur_state,
421 .set_cur_state = pwm_fan_set_cur_state,
422};
423
424static int pwm_fan_of_get_cooling_data(struct device *dev,
425 struct pwm_fan_ctx *ctx)
426{
427 struct device_node *np = dev->of_node;
428 int num, i, ret;
429
430 if (!of_property_present(np, "cooling-levels"))
431 return 0;
432
433 ret = of_property_count_u32_elems(np, "cooling-levels");
434 if (ret <= 0) {
435 dev_err(dev, "Wrong data!\n");
436 return ret ? : -EINVAL;
437 }
438
439 num = ret;
440 ctx->pwm_fan_cooling_levels = devm_kcalloc(dev, num, sizeof(u32),
441 GFP_KERNEL);
442 if (!ctx->pwm_fan_cooling_levels)
443 return -ENOMEM;
444
445 ret = of_property_read_u32_array(np, "cooling-levels",
446 ctx->pwm_fan_cooling_levels, num);
447 if (ret) {
448 dev_err(dev, "Property 'cooling-levels' cannot be read!\n");
449 return ret;
450 }
451
452 for (i = 0; i < num; i++) {
453 if (ctx->pwm_fan_cooling_levels[i] > MAX_PWM) {
454 dev_err(dev, "PWM fan state[%d]:%d > %d\n", i,
455 ctx->pwm_fan_cooling_levels[i], MAX_PWM);
456 return -EINVAL;
457 }
458 }
459
460 ctx->pwm_fan_max_state = num - 1;
461
462 return 0;
463}
464
465static void pwm_fan_cleanup(void *__ctx)
466{
467 struct pwm_fan_ctx *ctx = __ctx;
468
469 del_timer_sync(&ctx->rpm_timer);
470 /* Switch off everything */
471 ctx->enable_mode = pwm_disable_reg_disable;
472 pwm_fan_power_off(ctx);
473}
474
475static int pwm_fan_probe(struct platform_device *pdev)
476{
477 struct thermal_cooling_device *cdev;
478 struct device *dev = &pdev->dev;
479 struct pwm_fan_ctx *ctx;
480 struct device *hwmon;
481 int ret;
482 const struct hwmon_channel_info **channels;
483 u32 *fan_channel_config;
484 int channel_count = 1; /* We always have a PWM channel. */
485 int i;
486
487 ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
488 if (!ctx)
489 return -ENOMEM;
490
491 mutex_init(&ctx->lock);
492
493 ctx->dev = &pdev->dev;
494 ctx->pwm = devm_pwm_get(dev, NULL);
495 if (IS_ERR(ctx->pwm))
496 return dev_err_probe(dev, PTR_ERR(ctx->pwm), "Could not get PWM\n");
497
498 platform_set_drvdata(pdev, ctx);
499
500 ctx->reg_en = devm_regulator_get_optional(dev, "fan");
501 if (IS_ERR(ctx->reg_en)) {
502 if (PTR_ERR(ctx->reg_en) != -ENODEV)
503 return PTR_ERR(ctx->reg_en);
504
505 ctx->reg_en = NULL;
506 }
507
508 pwm_init_state(ctx->pwm, &ctx->pwm_state);
509
510 /*
511 * PWM fans are controlled solely by the duty cycle of the PWM signal,
512 * they do not care about the exact timing. Thus set usage_power to true
513 * to allow less flexible hardware to work as a PWM source for fan
514 * control.
515 */
516 ctx->pwm_state.usage_power = true;
517
518 /*
519 * set_pwm assumes that MAX_PWM * (period - 1) fits into an unsigned
520 * long. Check this here to prevent the fan running at a too low
521 * frequency.
522 */
523 if (ctx->pwm_state.period > ULONG_MAX / MAX_PWM + 1) {
524 dev_err(dev, "Configured period too big\n");
525 return -EINVAL;
526 }
527
528 ctx->enable_mode = pwm_disable_reg_enable;
529
530 /*
531 * Set duty cycle to maximum allowed and enable PWM output as well as
532 * the regulator. In case of error nothing is changed
533 */
534 ret = set_pwm(ctx, MAX_PWM);
535 if (ret) {
536 dev_err(dev, "Failed to configure PWM: %d\n", ret);
537 return ret;
538 }
539 timer_setup(&ctx->rpm_timer, sample_timer, 0);
540 ret = devm_add_action_or_reset(dev, pwm_fan_cleanup, ctx);
541 if (ret)
542 return ret;
543
544 ctx->tach_count = platform_irq_count(pdev);
545 if (ctx->tach_count < 0)
546 return dev_err_probe(dev, ctx->tach_count,
547 "Could not get number of fan tachometer inputs\n");
548 dev_dbg(dev, "%d fan tachometer inputs\n", ctx->tach_count);
549
550 if (ctx->tach_count) {
551 channel_count++; /* We also have a FAN channel. */
552
553 ctx->tachs = devm_kcalloc(dev, ctx->tach_count,
554 sizeof(struct pwm_fan_tach),
555 GFP_KERNEL);
556 if (!ctx->tachs)
557 return -ENOMEM;
558
559 ctx->fan_channel.type = hwmon_fan;
560 fan_channel_config = devm_kcalloc(dev, ctx->tach_count + 1,
561 sizeof(u32), GFP_KERNEL);
562 if (!fan_channel_config)
563 return -ENOMEM;
564 ctx->fan_channel.config = fan_channel_config;
565 }
566
567 channels = devm_kcalloc(dev, channel_count + 1,
568 sizeof(struct hwmon_channel_info *), GFP_KERNEL);
569 if (!channels)
570 return -ENOMEM;
571
572 channels[0] = HWMON_CHANNEL_INFO(pwm, HWMON_PWM_INPUT | HWMON_PWM_ENABLE);
573
574 for (i = 0; i < ctx->tach_count; i++) {
575 struct pwm_fan_tach *tach = &ctx->tachs[i];
576 u32 ppr = 2;
577
578 tach->irq = platform_get_irq(pdev, i);
579 if (tach->irq == -EPROBE_DEFER)
580 return tach->irq;
581 if (tach->irq > 0) {
582 ret = devm_request_irq(dev, tach->irq, pulse_handler, 0,
583 pdev->name, tach);
584 if (ret) {
585 dev_err(dev,
586 "Failed to request interrupt: %d\n",
587 ret);
588 return ret;
589 }
590 }
591
592 of_property_read_u32_index(dev->of_node,
593 "pulses-per-revolution",
594 i,
595 &ppr);
596 tach->pulses_per_revolution = ppr;
597 if (!tach->pulses_per_revolution) {
598 dev_err(dev, "pulses-per-revolution can't be zero.\n");
599 return -EINVAL;
600 }
601
602 fan_channel_config[i] = HWMON_F_INPUT;
603
604 dev_dbg(dev, "tach%d: irq=%d, pulses_per_revolution=%d\n",
605 i, tach->irq, tach->pulses_per_revolution);
606 }
607
608 if (ctx->tach_count > 0) {
609 ctx->sample_start = ktime_get();
610 mod_timer(&ctx->rpm_timer, jiffies + HZ);
611
612 channels[1] = &ctx->fan_channel;
613 }
614
615 ctx->info.ops = &pwm_fan_hwmon_ops;
616 ctx->info.info = channels;
617
618 hwmon = devm_hwmon_device_register_with_info(dev, "pwmfan",
619 ctx, &ctx->info, NULL);
620 if (IS_ERR(hwmon)) {
621 dev_err(dev, "Failed to register hwmon device\n");
622 return PTR_ERR(hwmon);
623 }
624
625 ret = pwm_fan_of_get_cooling_data(dev, ctx);
626 if (ret)
627 return ret;
628
629 ctx->pwm_fan_state = ctx->pwm_fan_max_state;
630 if (IS_ENABLED(CONFIG_THERMAL)) {
631 cdev = devm_thermal_of_cooling_device_register(dev,
632 dev->of_node, "pwm-fan", ctx, &pwm_fan_cooling_ops);
633 if (IS_ERR(cdev)) {
634 ret = PTR_ERR(cdev);
635 dev_err(dev,
636 "Failed to register pwm-fan as cooling device: %d\n",
637 ret);
638 return ret;
639 }
640 ctx->cdev = cdev;
641 }
642
643 return 0;
644}
645
646static void pwm_fan_shutdown(struct platform_device *pdev)
647{
648 struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev);
649
650 pwm_fan_cleanup(ctx);
651}
652
653static int pwm_fan_suspend(struct device *dev)
654{
655 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
656
657 return pwm_fan_power_off(ctx);
658}
659
660static int pwm_fan_resume(struct device *dev)
661{
662 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
663
664 return set_pwm(ctx, ctx->pwm_value);
665}
666
667static DEFINE_SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume);
668
669static const struct of_device_id of_pwm_fan_match[] = {
670 { .compatible = "pwm-fan", },
671 {},
672};
673MODULE_DEVICE_TABLE(of, of_pwm_fan_match);
674
675static struct platform_driver pwm_fan_driver = {
676 .probe = pwm_fan_probe,
677 .shutdown = pwm_fan_shutdown,
678 .driver = {
679 .name = "pwm-fan",
680 .pm = pm_sleep_ptr(&pwm_fan_pm),
681 .of_match_table = of_pwm_fan_match,
682 },
683};
684
685module_platform_driver(pwm_fan_driver);
686
687MODULE_AUTHOR("Kamil Debski <k.debski@samsung.com>");
688MODULE_ALIAS("platform:pwm-fan");
689MODULE_DESCRIPTION("PWM FAN driver");
690MODULE_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/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");