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