summaryrefslogtreecommitdiff
path: root/drivers/hwmon/gpio-fan.c
blob: e75db6f64e8cee897a543289d80f2abf2497fdd3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * gpio-fan.c - Hwmon driver for fans connected to GPIO lines.
 *
 * Copyright (C) 2010 LaCie
 *
 * Author: Simon Guinot <sguinot@lacie.com>
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/platform_device.h>
#include <linux/err.h>
#include <linux/kstrtox.h>
#include <linux/mutex.h>
#include <linux/hwmon.h>
#include <linux/gpio/consumer.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/thermal.h>

struct gpio_fan_speed {
	int rpm;
	int ctrl_val;
};

struct gpio_fan_data {
	struct device		*dev;
	struct device		*hwmon_dev;
	/* Cooling device if any */
	struct thermal_cooling_device *cdev;
	struct mutex		lock; /* lock GPIOs operations. */
	int			num_gpios;
	struct gpio_desc	**gpios;
	int			num_speed;
	struct gpio_fan_speed	*speed;
	int			speed_index;
	int			resume_speed;
	bool			pwm_enable;
	struct gpio_desc	*alarm_gpio;
	struct work_struct	alarm_work;
};

/*
 * Alarm GPIO.
 */

static void fan_alarm_notify(struct work_struct *ws)
{
	struct gpio_fan_data *fan_data =
		container_of(ws, struct gpio_fan_data, alarm_work);

	sysfs_notify(&fan_data->hwmon_dev->kobj, NULL, "fan1_alarm");
	kobject_uevent(&fan_data->hwmon_dev->kobj, KOBJ_CHANGE);
}

static irqreturn_t fan_alarm_irq_handler(int irq, void *dev_id)
{
	struct gpio_fan_data *fan_data = dev_id;

	schedule_work(&fan_data->alarm_work);

	return IRQ_NONE;
}

static ssize_t fan1_alarm_show(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);

	return sprintf(buf, "%d\n",
		       gpiod_get_value_cansleep(fan_data->alarm_gpio));
}

static DEVICE_ATTR_RO(fan1_alarm);

static int fan_alarm_init(struct gpio_fan_data *fan_data)
{
	int alarm_irq;
	struct device *dev = fan_data->dev;

	/*
	 * If the alarm GPIO don't support interrupts, just leave
	 * without initializing the fail notification support.
	 */
	alarm_irq = gpiod_to_irq(fan_data->alarm_gpio);
	if (alarm_irq <= 0)
		return 0;

	INIT_WORK(&fan_data->alarm_work, fan_alarm_notify);
	irq_set_irq_type(alarm_irq, IRQ_TYPE_EDGE_BOTH);
	return devm_request_irq(dev, alarm_irq, fan_alarm_irq_handler,
				IRQF_SHARED, "GPIO fan alarm", fan_data);
}

/*
 * Control GPIOs.
 */

/* Must be called with fan_data->lock held, except during initialization. */
static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val)
{
	int i;

	for (i = 0; i < fan_data->num_gpios; i++)
		gpiod_set_value_cansleep(fan_data->gpios[i],
					 (ctrl_val >> i) & 1);
}

static int __get_fan_ctrl(struct gpio_fan_data *fan_data)
{
	int i;
	int ctrl_val = 0;

	for (i = 0; i < fan_data->num_gpios; i++) {
		int value;

		value = gpiod_get_value_cansleep(fan_data->gpios[i]);
		ctrl_val |= (value << i);
	}
	return ctrl_val;
}

/* Must be called with fan_data->lock held, except during initialization. */
static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index)
{
	if (fan_data->speed_index == speed_index)
		return;

	__set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val);
	fan_data->speed_index = speed_index;
}

static int get_fan_speed_index(struct gpio_fan_data *fan_data)
{
	int ctrl_val = __get_fan_ctrl(fan_data);
	int i;

	for (i = 0; i < fan_data->num_speed; i++)
		if (fan_data->speed[i].ctrl_val == ctrl_val)
			return i;

	dev_warn(fan_data->dev,
		 "missing speed array entry for GPIO value 0x%x\n", ctrl_val);

	return -ENODEV;
}

static int rpm_to_speed_index(struct gpio_fan_data *fan_data, unsigned long rpm)
{
	struct gpio_fan_speed *speed = fan_data->speed;
	int i;

	for (i = 0; i < fan_data->num_speed; i++)
		if (speed[i].rpm >= rpm)
			return i;

	return fan_data->num_speed - 1;
}

static ssize_t pwm1_show(struct device *dev, struct device_attribute *attr,
			 char *buf)
{
	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
	u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1);

	return sprintf(buf, "%d\n", pwm);
}

static ssize_t pwm1_store(struct device *dev, struct device_attribute *attr,
			  const char *buf, size_t count)
{
	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
	unsigned long pwm;
	int speed_index;
	int ret = count;

	if (kstrtoul(buf, 10, &pwm) || pwm > 255)
		return -EINVAL;

	mutex_lock(&fan_data->lock);

	if (!fan_data->pwm_enable) {
		ret = -EPERM;
		goto exit_unlock;
	}

	speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255);
	set_fan_speed(fan_data, speed_index);

exit_unlock:
	mutex_unlock(&fan_data->lock);

	return ret;
}

static ssize_t pwm1_enable_show(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);

	return sprintf(buf, "%d\n", fan_data->pwm_enable);
}

static ssize_t pwm1_enable_store(struct device *dev,
				 struct device_attribute *attr,
				 const char *buf, size_t count)
{
	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
	unsigned long val;

	if (kstrtoul(buf, 10, &val) || val > 1)
		return -EINVAL;

	if (fan_data->pwm_enable == val)
		return count;

	mutex_lock(&fan_data->lock);

	fan_data->pwm_enable = val;

	/* Disable manual control mode: set fan at full speed. */
	if (val == 0)
		set_fan_speed(fan_data, fan_data->num_speed - 1);

	mutex_unlock(&fan_data->lock);

	return count;
}

static ssize_t pwm1_mode_show(struct device *dev,
			      struct device_attribute *attr, char *buf)
{
	return sprintf(buf, "0\n");
}

static ssize_t fan1_min_show(struct device *dev,
			     struct device_attribute *attr, char *buf)
{
	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);

	return sprintf(buf, "%d\n", fan_data->speed[0].rpm);
}

static ssize_t fan1_max_show(struct device *dev,
			     struct device_attribute *attr, char *buf)
{
	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);

	return sprintf(buf, "%d\n",
		       fan_data->speed[fan_data->num_speed - 1].rpm);
}

static ssize_t fan1_input_show(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);

	return sprintf(buf, "%d\n", fan_data->speed[fan_data->speed_index].rpm);
}

static ssize_t set_rpm(struct device *dev, struct device_attribute *attr,
		       const char *buf, size_t count)
{
	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
	unsigned long rpm;
	int ret = count;

	if (kstrtoul(buf, 10, &rpm))
		return -EINVAL;

	mutex_lock(&fan_data->lock);

	if (!fan_data->pwm_enable) {
		ret = -EPERM;
		goto exit_unlock;
	}

	set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm));

exit_unlock:
	mutex_unlock(&fan_data->lock);

	return ret;
}

static DEVICE_ATTR_RW(pwm1);
static DEVICE_ATTR_RW(pwm1_enable);
static DEVICE_ATTR_RO(pwm1_mode);
static DEVICE_ATTR_RO(fan1_min);
static DEVICE_ATTR_RO(fan1_max);
static DEVICE_ATTR_RO(fan1_input);
static DEVICE_ATTR(fan1_target, 0644, fan1_input_show, set_rpm);

static umode_t gpio_fan_is_visible(struct kobject *kobj,
				   struct attribute *attr, int index)
{
	struct device *dev = kobj_to_dev(kobj);
	struct gpio_fan_data *data = dev_get_drvdata(dev);

	if (index == 0 && !data->alarm_gpio)
		return 0;
	if (index > 0 && !data->gpios)
		return 0;

	return attr->mode;
}

static struct attribute *gpio_fan_attributes[] = {
	&dev_attr_fan1_alarm.attr,		/* 0 */
	&dev_attr_pwm1.attr,			/* 1 */
	&dev_attr_pwm1_enable.attr,
	&dev_attr_pwm1_mode.attr,
	&dev_attr_fan1_input.attr,
	&dev_attr_fan1_target.attr,
	&dev_attr_fan1_min.attr,
	&dev_attr_fan1_max.attr,
	NULL
};

static const struct attribute_group gpio_fan_group = {
	.attrs = gpio_fan_attributes,
	.is_visible = gpio_fan_is_visible,
};

static const struct attribute_group *gpio_fan_groups[] = {
	&gpio_fan_group,
	NULL
};

static int fan_ctrl_init(struct gpio_fan_data *fan_data)
{
	int num_gpios = fan_data->num_gpios;
	struct gpio_desc **gpios = fan_data->gpios;
	int i, err;

	for (i = 0; i < num_gpios; i++) {
		/*
		 * The GPIO descriptors were retrieved with GPIOD_ASIS so here
		 * we set the GPIO into output mode, carefully preserving the
		 * current value by setting it to whatever it is already set
		 * (no surprise changes in default fan speed).
		 */
		err = gpiod_direction_output(gpios[i],
					gpiod_get_value_cansleep(gpios[i]));
		if (err)
			return err;
	}

	fan_data->pwm_enable = true; /* Enable manual fan speed control. */
	fan_data->speed_index = get_fan_speed_index(fan_data);
	if (fan_data->speed_index < 0)
		return fan_data->speed_index;

	return 0;
}

static int gpio_fan_get_max_state(struct thermal_cooling_device *cdev,
				  unsigned long *state)
{
	struct gpio_fan_data *fan_data = cdev->devdata;

	if (!fan_data)
		return -EINVAL;

	*state = fan_data->num_speed - 1;
	return 0;
}

static int gpio_fan_get_cur_state(struct thermal_cooling_device *cdev,
				  unsigned long *state)
{
	struct gpio_fan_data *fan_data = cdev->devdata;

	if (!fan_data)
		return -EINVAL;

	*state = fan_data->speed_index;
	return 0;
}

static int gpio_fan_set_cur_state(struct thermal_cooling_device *cdev,
				  unsigned long state)
{
	struct gpio_fan_data *fan_data = cdev->devdata;

	if (!fan_data)
		return -EINVAL;

	if (state >= fan_data->num_speed)
		return -EINVAL;

	set_fan_speed(fan_data, state);
	return 0;
}

static const struct thermal_cooling_device_ops gpio_fan_cool_ops = {
	.get_max_state = gpio_fan_get_max_state,
	.get_cur_state = gpio_fan_get_cur_state,
	.set_cur_state = gpio_fan_set_cur_state,
};

/*
 * Translate OpenFirmware node properties into platform_data
 */
static int gpio_fan_get_of_data(struct gpio_fan_data *fan_data)
{
	struct gpio_fan_speed *speed;
	struct device *dev = fan_data->dev;
	struct device_node *np = dev->of_node;
	struct gpio_desc **gpios;
	unsigned i;
	u32 u;
	struct property *prop;
	const __be32 *p;

	/* Alarm GPIO if one exists */
	fan_data->alarm_gpio = devm_gpiod_get_optional(dev, "alarm", GPIOD_IN);
	if (IS_ERR(fan_data->alarm_gpio))
		return PTR_ERR(fan_data->alarm_gpio);

	/* Fill GPIO pin array */
	fan_data->num_gpios = gpiod_count(dev, NULL);
	if (fan_data->num_gpios <= 0) {
		if (fan_data->alarm_gpio)
			return 0;
		dev_err(dev, "DT properties empty / missing");
		return -ENODEV;
	}
	gpios = devm_kcalloc(dev,
			     fan_data->num_gpios, sizeof(struct gpio_desc *),
			     GFP_KERNEL);
	if (!gpios)
		return -ENOMEM;
	for (i = 0; i < fan_data->num_gpios; i++) {
		gpios[i] = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS);
		if (IS_ERR(gpios[i]))
			return PTR_ERR(gpios[i]);
	}
	fan_data->gpios = gpios;

	/* Get number of RPM/ctrl_val pairs in speed map */
	prop = of_find_property(np, "gpio-fan,speed-map", &i);
	if (!prop) {
		dev_err(dev, "gpio-fan,speed-map DT property missing");
		return -ENODEV;
	}
	i = i / sizeof(u32);
	if (i == 0 || i & 1) {
		dev_err(dev, "gpio-fan,speed-map contains zero/odd number of entries");
		return -ENODEV;
	}
	fan_data->num_speed = i / 2;

	/*
	 * Populate speed map
	 * Speed map is in the form <RPM ctrl_val RPM ctrl_val ...>
	 * this needs splitting into pairs to create gpio_fan_speed structs
	 */
	speed = devm_kcalloc(dev,
			fan_data->num_speed, sizeof(struct gpio_fan_speed),
			GFP_KERNEL);
	if (!speed)
		return -ENOMEM;
	p = NULL;
	for (i = 0; i < fan_data->num_speed; i++) {
		p = of_prop_next_u32(prop, p, &u);
		if (!p)
			return -ENODEV;
		speed[i].rpm = u;
		p = of_prop_next_u32(prop, p, &u);
		if (!p)
			return -ENODEV;
		speed[i].ctrl_val = u;
	}
	fan_data->speed = speed;

	return 0;
}

static const struct of_device_id of_gpio_fan_match[] = {
	{ .compatible = "gpio-fan", },
	{},
};
MODULE_DEVICE_TABLE(of, of_gpio_fan_match);

static void gpio_fan_stop(void *data)
{
	set_fan_speed(data, 0);
}

static int gpio_fan_probe(struct platform_device *pdev)
{
	int err;
	struct gpio_fan_data *fan_data;
	struct device *dev = &pdev->dev;
	struct device_node *np = dev->of_node;

	fan_data = devm_kzalloc(dev, sizeof(struct gpio_fan_data),
				GFP_KERNEL);
	if (!fan_data)
		return -ENOMEM;

	fan_data->dev = dev;
	err = gpio_fan_get_of_data(fan_data);
	if (err)
		return err;

	platform_set_drvdata(pdev, fan_data);
	mutex_init(&fan_data->lock);

	/* Configure control GPIOs if available. */
	if (fan_data->gpios && fan_data->num_gpios > 0) {
		if (!fan_data->speed || fan_data->num_speed <= 1)
			return -EINVAL;
		err = fan_ctrl_init(fan_data);
		if (err)
			return err;
		err = devm_add_action_or_reset(dev, gpio_fan_stop, fan_data);
		if (err)
			return err;
	}

	/* Make this driver part of hwmon class. */
	fan_data->hwmon_dev =
		devm_hwmon_device_register_with_groups(dev,
						       "gpio_fan", fan_data,
						       gpio_fan_groups);
	if (IS_ERR(fan_data->hwmon_dev))
		return PTR_ERR(fan_data->hwmon_dev);

	/* Configure alarm GPIO if available. */
	if (fan_data->alarm_gpio) {
		err = fan_alarm_init(fan_data);
		if (err)
			return err;
	}

	/* Optional cooling device register for Device tree platforms */
	fan_data->cdev = devm_thermal_of_cooling_device_register(dev, np,
				"gpio-fan", fan_data, &gpio_fan_cool_ops);

	dev_info(dev, "GPIO fan initialized\n");

	return 0;
}

static void gpio_fan_shutdown(struct platform_device *pdev)
{
	struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);

	if (fan_data->gpios)
		set_fan_speed(fan_data, 0);
}

static int gpio_fan_suspend(struct device *dev)
{
	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);

	if (fan_data->gpios) {
		fan_data->resume_speed = fan_data->speed_index;
		set_fan_speed(fan_data, 0);
	}

	return 0;
}

static int gpio_fan_resume(struct device *dev)
{
	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);

	if (fan_data->gpios)
		set_fan_speed(fan_data, fan_data->resume_speed);

	return 0;
}

static DEFINE_SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume);

static struct platform_driver gpio_fan_driver = {
	.probe		= gpio_fan_probe,
	.shutdown	= gpio_fan_shutdown,
	.driver	= {
		.name	= "gpio-fan",
		.pm	= pm_sleep_ptr(&gpio_fan_pm),
		.of_match_table = of_match_ptr(of_gpio_fan_match),
	},
};

module_platform_driver(gpio_fan_driver);

MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
MODULE_DESCRIPTION("GPIO FAN driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:gpio-fan");