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