1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * gpio-fan.c - Hwmon driver for fans connected to GPIO lines.
4 *
5 * Copyright (C) 2010 LaCie
6 *
7 * Author: Simon Guinot <sguinot@lacie.com>
8 */
9
10 #include <linux/module.h>
11 #include <linux/init.h>
12 #include <linux/slab.h>
13 #include <linux/interrupt.h>
14 #include <linux/irq.h>
15 #include <linux/platform_device.h>
16 #include <linux/err.h>
17 #include <linux/kstrtox.h>
18 #include <linux/mutex.h>
19 #include <linux/hwmon.h>
20 #include <linux/gpio/consumer.h>
21 #include <linux/of.h>
22 #include <linux/of_platform.h>
23 #include <linux/thermal.h>
24
25 struct gpio_fan_speed {
26 int rpm;
27 int ctrl_val;
28 };
29
30 struct gpio_fan_data {
31 struct device *dev;
32 struct device *hwmon_dev;
33 /* Cooling device if any */
34 struct thermal_cooling_device *cdev;
35 struct mutex lock; /* lock GPIOs operations. */
36 int num_gpios;
37 struct gpio_desc **gpios;
38 int num_speed;
39 struct gpio_fan_speed *speed;
40 int speed_index;
41 int resume_speed;
42 bool pwm_enable;
43 struct gpio_desc *alarm_gpio;
44 struct work_struct alarm_work;
45 };
46
47 /*
48 * Alarm GPIO.
49 */
50
fan_alarm_notify(struct work_struct * ws)51 static void fan_alarm_notify(struct work_struct *ws)
52 {
53 struct gpio_fan_data *fan_data =
54 container_of(ws, struct gpio_fan_data, alarm_work);
55
56 sysfs_notify(&fan_data->hwmon_dev->kobj, NULL, "fan1_alarm");
57 kobject_uevent(&fan_data->hwmon_dev->kobj, KOBJ_CHANGE);
58 }
59
fan_alarm_irq_handler(int irq,void * dev_id)60 static irqreturn_t fan_alarm_irq_handler(int irq, void *dev_id)
61 {
62 struct gpio_fan_data *fan_data = dev_id;
63
64 schedule_work(&fan_data->alarm_work);
65
66 return IRQ_NONE;
67 }
68
fan1_alarm_show(struct device * dev,struct device_attribute * attr,char * buf)69 static ssize_t fan1_alarm_show(struct device *dev,
70 struct device_attribute *attr, char *buf)
71 {
72 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
73
74 return sprintf(buf, "%d\n",
75 gpiod_get_value_cansleep(fan_data->alarm_gpio));
76 }
77
78 static DEVICE_ATTR_RO(fan1_alarm);
79
fan_alarm_init(struct gpio_fan_data * fan_data)80 static int fan_alarm_init(struct gpio_fan_data *fan_data)
81 {
82 int alarm_irq;
83 struct device *dev = fan_data->dev;
84
85 /*
86 * If the alarm GPIO don't support interrupts, just leave
87 * without initializing the fail notification support.
88 */
89 alarm_irq = gpiod_to_irq(fan_data->alarm_gpio);
90 if (alarm_irq <= 0)
91 return 0;
92
93 INIT_WORK(&fan_data->alarm_work, fan_alarm_notify);
94 irq_set_irq_type(alarm_irq, IRQ_TYPE_EDGE_BOTH);
95 return devm_request_irq(dev, alarm_irq, fan_alarm_irq_handler,
96 IRQF_SHARED, "GPIO fan alarm", fan_data);
97 }
98
99 /*
100 * Control GPIOs.
101 */
102
103 /* Must be called with fan_data->lock held, except during initialization. */
__set_fan_ctrl(struct gpio_fan_data * fan_data,int ctrl_val)104 static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val)
105 {
106 int i;
107
108 for (i = 0; i < fan_data->num_gpios; i++)
109 gpiod_set_value_cansleep(fan_data->gpios[i],
110 (ctrl_val >> i) & 1);
111 }
112
__get_fan_ctrl(struct gpio_fan_data * fan_data)113 static int __get_fan_ctrl(struct gpio_fan_data *fan_data)
114 {
115 int i;
116 int ctrl_val = 0;
117
118 for (i = 0; i < fan_data->num_gpios; i++) {
119 int value;
120
121 value = gpiod_get_value_cansleep(fan_data->gpios[i]);
122 ctrl_val |= (value << i);
123 }
124 return ctrl_val;
125 }
126
127 /* Must be called with fan_data->lock held, except during initialization. */
set_fan_speed(struct gpio_fan_data * fan_data,int speed_index)128 static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index)
129 {
130 if (fan_data->speed_index == speed_index)
131 return;
132
133 __set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val);
134 fan_data->speed_index = speed_index;
135 }
136
get_fan_speed_index(struct gpio_fan_data * fan_data)137 static int get_fan_speed_index(struct gpio_fan_data *fan_data)
138 {
139 int ctrl_val = __get_fan_ctrl(fan_data);
140 int i;
141
142 for (i = 0; i < fan_data->num_speed; i++)
143 if (fan_data->speed[i].ctrl_val == ctrl_val)
144 return i;
145
146 dev_warn(fan_data->dev,
147 "missing speed array entry for GPIO value 0x%x\n", ctrl_val);
148
149 return -ENODEV;
150 }
151
rpm_to_speed_index(struct gpio_fan_data * fan_data,unsigned long rpm)152 static int rpm_to_speed_index(struct gpio_fan_data *fan_data, unsigned long rpm)
153 {
154 struct gpio_fan_speed *speed = fan_data->speed;
155 int i;
156
157 for (i = 0; i < fan_data->num_speed; i++)
158 if (speed[i].rpm >= rpm)
159 return i;
160
161 return fan_data->num_speed - 1;
162 }
163
pwm1_show(struct device * dev,struct device_attribute * attr,char * buf)164 static ssize_t pwm1_show(struct device *dev, struct device_attribute *attr,
165 char *buf)
166 {
167 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
168 u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1);
169
170 return sprintf(buf, "%d\n", pwm);
171 }
172
pwm1_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)173 static ssize_t pwm1_store(struct device *dev, struct device_attribute *attr,
174 const char *buf, size_t count)
175 {
176 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
177 unsigned long pwm;
178 int speed_index;
179 int ret = count;
180
181 if (kstrtoul(buf, 10, &pwm) || pwm > 255)
182 return -EINVAL;
183
184 mutex_lock(&fan_data->lock);
185
186 if (!fan_data->pwm_enable) {
187 ret = -EPERM;
188 goto exit_unlock;
189 }
190
191 speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255);
192 set_fan_speed(fan_data, speed_index);
193
194 exit_unlock:
195 mutex_unlock(&fan_data->lock);
196
197 return ret;
198 }
199
pwm1_enable_show(struct device * dev,struct device_attribute * attr,char * buf)200 static ssize_t pwm1_enable_show(struct device *dev,
201 struct device_attribute *attr, char *buf)
202 {
203 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
204
205 return sprintf(buf, "%d\n", fan_data->pwm_enable);
206 }
207
pwm1_enable_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)208 static ssize_t pwm1_enable_store(struct device *dev,
209 struct device_attribute *attr,
210 const char *buf, size_t count)
211 {
212 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
213 unsigned long val;
214
215 if (kstrtoul(buf, 10, &val) || val > 1)
216 return -EINVAL;
217
218 if (fan_data->pwm_enable == val)
219 return count;
220
221 mutex_lock(&fan_data->lock);
222
223 fan_data->pwm_enable = val;
224
225 /* Disable manual control mode: set fan at full speed. */
226 if (val == 0)
227 set_fan_speed(fan_data, fan_data->num_speed - 1);
228
229 mutex_unlock(&fan_data->lock);
230
231 return count;
232 }
233
pwm1_mode_show(struct device * dev,struct device_attribute * attr,char * buf)234 static ssize_t pwm1_mode_show(struct device *dev,
235 struct device_attribute *attr, char *buf)
236 {
237 return sprintf(buf, "0\n");
238 }
239
fan1_min_show(struct device * dev,struct device_attribute * attr,char * buf)240 static ssize_t fan1_min_show(struct device *dev,
241 struct device_attribute *attr, char *buf)
242 {
243 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
244
245 return sprintf(buf, "%d\n", fan_data->speed[0].rpm);
246 }
247
fan1_max_show(struct device * dev,struct device_attribute * attr,char * buf)248 static ssize_t fan1_max_show(struct device *dev,
249 struct device_attribute *attr, char *buf)
250 {
251 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
252
253 return sprintf(buf, "%d\n",
254 fan_data->speed[fan_data->num_speed - 1].rpm);
255 }
256
fan1_input_show(struct device * dev,struct device_attribute * attr,char * buf)257 static ssize_t fan1_input_show(struct device *dev,
258 struct device_attribute *attr, char *buf)
259 {
260 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
261
262 return sprintf(buf, "%d\n", fan_data->speed[fan_data->speed_index].rpm);
263 }
264
set_rpm(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)265 static ssize_t set_rpm(struct device *dev, struct device_attribute *attr,
266 const char *buf, size_t count)
267 {
268 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
269 unsigned long rpm;
270 int ret = count;
271
272 if (kstrtoul(buf, 10, &rpm))
273 return -EINVAL;
274
275 mutex_lock(&fan_data->lock);
276
277 if (!fan_data->pwm_enable) {
278 ret = -EPERM;
279 goto exit_unlock;
280 }
281
282 set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm));
283
284 exit_unlock:
285 mutex_unlock(&fan_data->lock);
286
287 return ret;
288 }
289
290 static DEVICE_ATTR_RW(pwm1);
291 static DEVICE_ATTR_RW(pwm1_enable);
292 static DEVICE_ATTR_RO(pwm1_mode);
293 static DEVICE_ATTR_RO(fan1_min);
294 static DEVICE_ATTR_RO(fan1_max);
295 static DEVICE_ATTR_RO(fan1_input);
296 static DEVICE_ATTR(fan1_target, 0644, fan1_input_show, set_rpm);
297
gpio_fan_is_visible(struct kobject * kobj,struct attribute * attr,int index)298 static umode_t gpio_fan_is_visible(struct kobject *kobj,
299 struct attribute *attr, int index)
300 {
301 struct device *dev = kobj_to_dev(kobj);
302 struct gpio_fan_data *data = dev_get_drvdata(dev);
303
304 if (index == 0 && !data->alarm_gpio)
305 return 0;
306 if (index > 0 && !data->gpios)
307 return 0;
308
309 return attr->mode;
310 }
311
312 static struct attribute *gpio_fan_attributes[] = {
313 &dev_attr_fan1_alarm.attr, /* 0 */
314 &dev_attr_pwm1.attr, /* 1 */
315 &dev_attr_pwm1_enable.attr,
316 &dev_attr_pwm1_mode.attr,
317 &dev_attr_fan1_input.attr,
318 &dev_attr_fan1_target.attr,
319 &dev_attr_fan1_min.attr,
320 &dev_attr_fan1_max.attr,
321 NULL
322 };
323
324 static const struct attribute_group gpio_fan_group = {
325 .attrs = gpio_fan_attributes,
326 .is_visible = gpio_fan_is_visible,
327 };
328
329 static const struct attribute_group *gpio_fan_groups[] = {
330 &gpio_fan_group,
331 NULL
332 };
333
fan_ctrl_init(struct gpio_fan_data * fan_data)334 static int fan_ctrl_init(struct gpio_fan_data *fan_data)
335 {
336 int num_gpios = fan_data->num_gpios;
337 struct gpio_desc **gpios = fan_data->gpios;
338 int i, err;
339
340 for (i = 0; i < num_gpios; i++) {
341 /*
342 * The GPIO descriptors were retrieved with GPIOD_ASIS so here
343 * we set the GPIO into output mode, carefully preserving the
344 * current value by setting it to whatever it is already set
345 * (no surprise changes in default fan speed).
346 */
347 err = gpiod_direction_output(gpios[i],
348 gpiod_get_value_cansleep(gpios[i]));
349 if (err)
350 return err;
351 }
352
353 fan_data->pwm_enable = true; /* Enable manual fan speed control. */
354 fan_data->speed_index = get_fan_speed_index(fan_data);
355 if (fan_data->speed_index < 0)
356 return fan_data->speed_index;
357
358 return 0;
359 }
360
gpio_fan_get_max_state(struct thermal_cooling_device * cdev,unsigned long * state)361 static int gpio_fan_get_max_state(struct thermal_cooling_device *cdev,
362 unsigned long *state)
363 {
364 struct gpio_fan_data *fan_data = cdev->devdata;
365
366 if (!fan_data)
367 return -EINVAL;
368
369 *state = fan_data->num_speed - 1;
370 return 0;
371 }
372
gpio_fan_get_cur_state(struct thermal_cooling_device * cdev,unsigned long * state)373 static int gpio_fan_get_cur_state(struct thermal_cooling_device *cdev,
374 unsigned long *state)
375 {
376 struct gpio_fan_data *fan_data = cdev->devdata;
377
378 if (!fan_data)
379 return -EINVAL;
380
381 *state = fan_data->speed_index;
382 return 0;
383 }
384
gpio_fan_set_cur_state(struct thermal_cooling_device * cdev,unsigned long state)385 static int gpio_fan_set_cur_state(struct thermal_cooling_device *cdev,
386 unsigned long state)
387 {
388 struct gpio_fan_data *fan_data = cdev->devdata;
389
390 if (!fan_data)
391 return -EINVAL;
392
393 if (state >= fan_data->num_speed)
394 return -EINVAL;
395
396 mutex_lock(&fan_data->lock);
397
398 set_fan_speed(fan_data, state);
399
400 mutex_unlock(&fan_data->lock);
401
402 return 0;
403 }
404
405 static const struct thermal_cooling_device_ops gpio_fan_cool_ops = {
406 .get_max_state = gpio_fan_get_max_state,
407 .get_cur_state = gpio_fan_get_cur_state,
408 .set_cur_state = gpio_fan_set_cur_state,
409 };
410
411 /*
412 * Translate OpenFirmware node properties into platform_data
413 */
gpio_fan_get_of_data(struct gpio_fan_data * fan_data)414 static int gpio_fan_get_of_data(struct gpio_fan_data *fan_data)
415 {
416 struct gpio_fan_speed *speed;
417 struct device *dev = fan_data->dev;
418 struct device_node *np = dev->of_node;
419 struct gpio_desc **gpios;
420 unsigned i;
421 u32 u;
422 struct property *prop;
423 const __be32 *p;
424
425 /* Alarm GPIO if one exists */
426 fan_data->alarm_gpio = devm_gpiod_get_optional(dev, "alarm", GPIOD_IN);
427 if (IS_ERR(fan_data->alarm_gpio))
428 return PTR_ERR(fan_data->alarm_gpio);
429
430 /* Fill GPIO pin array */
431 fan_data->num_gpios = gpiod_count(dev, NULL);
432 if (fan_data->num_gpios <= 0) {
433 if (fan_data->alarm_gpio)
434 return 0;
435 dev_err(dev, "DT properties empty / missing");
436 return -ENODEV;
437 }
438 gpios = devm_kcalloc(dev,
439 fan_data->num_gpios, sizeof(struct gpio_desc *),
440 GFP_KERNEL);
441 if (!gpios)
442 return -ENOMEM;
443 for (i = 0; i < fan_data->num_gpios; i++) {
444 gpios[i] = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS);
445 if (IS_ERR(gpios[i]))
446 return PTR_ERR(gpios[i]);
447 }
448 fan_data->gpios = gpios;
449
450 /* Get number of RPM/ctrl_val pairs in speed map */
451 prop = of_find_property(np, "gpio-fan,speed-map", &i);
452 if (!prop) {
453 dev_err(dev, "gpio-fan,speed-map DT property missing");
454 return -ENODEV;
455 }
456 i = i / sizeof(u32);
457 if (i == 0 || i & 1) {
458 dev_err(dev, "gpio-fan,speed-map contains zero/odd number of entries");
459 return -ENODEV;
460 }
461 fan_data->num_speed = i / 2;
462
463 /*
464 * Populate speed map
465 * Speed map is in the form <RPM ctrl_val RPM ctrl_val ...>
466 * this needs splitting into pairs to create gpio_fan_speed structs
467 */
468 speed = devm_kcalloc(dev,
469 fan_data->num_speed, sizeof(struct gpio_fan_speed),
470 GFP_KERNEL);
471 if (!speed)
472 return -ENOMEM;
473 p = NULL;
474 for (i = 0; i < fan_data->num_speed; i++) {
475 p = of_prop_next_u32(prop, p, &u);
476 if (!p)
477 return -ENODEV;
478 speed[i].rpm = u;
479 p = of_prop_next_u32(prop, p, &u);
480 if (!p)
481 return -ENODEV;
482 speed[i].ctrl_val = u;
483 }
484 fan_data->speed = speed;
485
486 return 0;
487 }
488
489 static const struct of_device_id of_gpio_fan_match[] = {
490 { .compatible = "gpio-fan", },
491 {},
492 };
493 MODULE_DEVICE_TABLE(of, of_gpio_fan_match);
494
gpio_fan_stop(void * data)495 static void gpio_fan_stop(void *data)
496 {
497 struct gpio_fan_data *fan_data = data;
498
499 mutex_lock(&fan_data->lock);
500 set_fan_speed(data, 0);
501 mutex_unlock(&fan_data->lock);
502 }
503
gpio_fan_probe(struct platform_device * pdev)504 static int gpio_fan_probe(struct platform_device *pdev)
505 {
506 int err;
507 struct gpio_fan_data *fan_data;
508 struct device *dev = &pdev->dev;
509 struct device_node *np = dev->of_node;
510
511 fan_data = devm_kzalloc(dev, sizeof(struct gpio_fan_data),
512 GFP_KERNEL);
513 if (!fan_data)
514 return -ENOMEM;
515
516 fan_data->dev = dev;
517 err = gpio_fan_get_of_data(fan_data);
518 if (err)
519 return err;
520
521 platform_set_drvdata(pdev, fan_data);
522 mutex_init(&fan_data->lock);
523
524 /* Configure control GPIOs if available. */
525 if (fan_data->gpios && fan_data->num_gpios > 0) {
526 if (!fan_data->speed || fan_data->num_speed <= 1)
527 return -EINVAL;
528 err = fan_ctrl_init(fan_data);
529 if (err)
530 return err;
531 err = devm_add_action_or_reset(dev, gpio_fan_stop, fan_data);
532 if (err)
533 return err;
534 }
535
536 /* Make this driver part of hwmon class. */
537 fan_data->hwmon_dev =
538 devm_hwmon_device_register_with_groups(dev,
539 "gpio_fan", fan_data,
540 gpio_fan_groups);
541 if (IS_ERR(fan_data->hwmon_dev))
542 return PTR_ERR(fan_data->hwmon_dev);
543
544 /* Configure alarm GPIO if available. */
545 if (fan_data->alarm_gpio) {
546 err = fan_alarm_init(fan_data);
547 if (err)
548 return err;
549 }
550
551 /* Optional cooling device register for Device tree platforms */
552 fan_data->cdev = devm_thermal_of_cooling_device_register(dev, np,
553 "gpio-fan", fan_data, &gpio_fan_cool_ops);
554
555 dev_info(dev, "GPIO fan initialized\n");
556
557 return 0;
558 }
559
gpio_fan_shutdown(struct platform_device * pdev)560 static void gpio_fan_shutdown(struct platform_device *pdev)
561 {
562 struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);
563
564 if (fan_data->gpios)
565 set_fan_speed(fan_data, 0);
566 }
567
gpio_fan_suspend(struct device * dev)568 static int gpio_fan_suspend(struct device *dev)
569 {
570 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
571
572 if (fan_data->gpios) {
573 fan_data->resume_speed = fan_data->speed_index;
574 mutex_lock(&fan_data->lock);
575 set_fan_speed(fan_data, 0);
576 mutex_unlock(&fan_data->lock);
577 }
578
579 return 0;
580 }
581
gpio_fan_resume(struct device * dev)582 static int gpio_fan_resume(struct device *dev)
583 {
584 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
585
586 if (fan_data->gpios) {
587 mutex_lock(&fan_data->lock);
588 set_fan_speed(fan_data, fan_data->resume_speed);
589 mutex_unlock(&fan_data->lock);
590 }
591
592 return 0;
593 }
594
595 static DEFINE_SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume);
596
597 static struct platform_driver gpio_fan_driver = {
598 .probe = gpio_fan_probe,
599 .shutdown = gpio_fan_shutdown,
600 .driver = {
601 .name = "gpio-fan",
602 .pm = pm_sleep_ptr(&gpio_fan_pm),
603 .of_match_table = of_gpio_fan_match,
604 },
605 };
606
607 module_platform_driver(gpio_fan_driver);
608
609 MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
610 MODULE_DESCRIPTION("GPIO FAN driver");
611 MODULE_LICENSE("GPL");
612 MODULE_ALIAS("platform:gpio-fan");
613