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 | |
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(kobj: &fan_data->hwmon_dev->kobj, NULL, attr: "fan1_alarm" ); |
57 | kobject_uevent(kobj: &fan_data->hwmon_dev->kobj, action: KOBJ_CHANGE); |
58 | } |
59 | |
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(work: &fan_data->alarm_work); |
65 | |
66 | return IRQ_NONE; |
67 | } |
68 | |
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, fmt: "%d\n" , |
75 | gpiod_get_value_cansleep(desc: fan_data->alarm_gpio)); |
76 | } |
77 | |
78 | static DEVICE_ATTR_RO(fan1_alarm); |
79 | |
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(desc: 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(irq: alarm_irq, type: IRQ_TYPE_EDGE_BOTH); |
95 | return devm_request_irq(dev, irq: alarm_irq, handler: fan_alarm_irq_handler, |
96 | IRQF_SHARED, devname: "GPIO fan alarm" , dev_id: fan_data); |
97 | } |
98 | |
99 | /* |
100 | * Control GPIOs. |
101 | */ |
102 | |
103 | /* Must be called with fan_data->lock held, except during initialization. */ |
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(desc: fan_data->gpios[i], |
110 | value: (ctrl_val >> i) & 1); |
111 | } |
112 | |
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(desc: 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. */ |
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, ctrl_val: fan_data->speed[speed_index].ctrl_val); |
134 | fan_data->speed_index = speed_index; |
135 | } |
136 | |
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 | |
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 | |
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, fmt: "%d\n" , pwm); |
171 | } |
172 | |
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(s: buf, base: 10, res: &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(lock: &fan_data->lock); |
196 | |
197 | return ret; |
198 | } |
199 | |
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, fmt: "%d\n" , fan_data->pwm_enable); |
206 | } |
207 | |
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(s: buf, base: 10, res: &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, speed_index: fan_data->num_speed - 1); |
228 | |
229 | mutex_unlock(lock: &fan_data->lock); |
230 | |
231 | return count; |
232 | } |
233 | |
234 | static ssize_t pwm1_mode_show(struct device *dev, |
235 | struct device_attribute *attr, char *buf) |
236 | { |
237 | return sprintf(buf, fmt: "0\n" ); |
238 | } |
239 | |
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, fmt: "%d\n" , fan_data->speed[0].rpm); |
246 | } |
247 | |
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, fmt: "%d\n" , |
254 | fan_data->speed[fan_data->num_speed - 1].rpm); |
255 | } |
256 | |
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, fmt: "%d\n" , fan_data->speed[fan_data->speed_index].rpm); |
263 | } |
264 | |
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(s: buf, base: 10, res: &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, speed_index: rpm_to_speed_index(fan_data, rpm)); |
283 | |
284 | exit_unlock: |
285 | mutex_unlock(lock: &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 | |
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 | |
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(desc: gpios[i], |
348 | value: gpiod_get_value_cansleep(desc: 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 | |
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 | |
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 | |
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 | set_fan_speed(fan_data, speed_index: state); |
397 | return 0; |
398 | } |
399 | |
400 | static const struct thermal_cooling_device_ops gpio_fan_cool_ops = { |
401 | .get_max_state = gpio_fan_get_max_state, |
402 | .get_cur_state = gpio_fan_get_cur_state, |
403 | .set_cur_state = gpio_fan_set_cur_state, |
404 | }; |
405 | |
406 | /* |
407 | * Translate OpenFirmware node properties into platform_data |
408 | */ |
409 | static int gpio_fan_get_of_data(struct gpio_fan_data *fan_data) |
410 | { |
411 | struct gpio_fan_speed *speed; |
412 | struct device *dev = fan_data->dev; |
413 | struct device_node *np = dev->of_node; |
414 | struct gpio_desc **gpios; |
415 | unsigned i; |
416 | u32 u; |
417 | struct property *prop; |
418 | const __be32 *p; |
419 | |
420 | /* Alarm GPIO if one exists */ |
421 | fan_data->alarm_gpio = devm_gpiod_get_optional(dev, con_id: "alarm" , flags: GPIOD_IN); |
422 | if (IS_ERR(ptr: fan_data->alarm_gpio)) |
423 | return PTR_ERR(ptr: fan_data->alarm_gpio); |
424 | |
425 | /* Fill GPIO pin array */ |
426 | fan_data->num_gpios = gpiod_count(dev, NULL); |
427 | if (fan_data->num_gpios <= 0) { |
428 | if (fan_data->alarm_gpio) |
429 | return 0; |
430 | dev_err(dev, "DT properties empty / missing" ); |
431 | return -ENODEV; |
432 | } |
433 | gpios = devm_kcalloc(dev, |
434 | n: fan_data->num_gpios, size: sizeof(struct gpio_desc *), |
435 | GFP_KERNEL); |
436 | if (!gpios) |
437 | return -ENOMEM; |
438 | for (i = 0; i < fan_data->num_gpios; i++) { |
439 | gpios[i] = devm_gpiod_get_index(dev, NULL, idx: i, flags: GPIOD_ASIS); |
440 | if (IS_ERR(ptr: gpios[i])) |
441 | return PTR_ERR(ptr: gpios[i]); |
442 | } |
443 | fan_data->gpios = gpios; |
444 | |
445 | /* Get number of RPM/ctrl_val pairs in speed map */ |
446 | prop = of_find_property(np, name: "gpio-fan,speed-map" , lenp: &i); |
447 | if (!prop) { |
448 | dev_err(dev, "gpio-fan,speed-map DT property missing" ); |
449 | return -ENODEV; |
450 | } |
451 | i = i / sizeof(u32); |
452 | if (i == 0 || i & 1) { |
453 | dev_err(dev, "gpio-fan,speed-map contains zero/odd number of entries" ); |
454 | return -ENODEV; |
455 | } |
456 | fan_data->num_speed = i / 2; |
457 | |
458 | /* |
459 | * Populate speed map |
460 | * Speed map is in the form <RPM ctrl_val RPM ctrl_val ...> |
461 | * this needs splitting into pairs to create gpio_fan_speed structs |
462 | */ |
463 | speed = devm_kcalloc(dev, |
464 | n: fan_data->num_speed, size: sizeof(struct gpio_fan_speed), |
465 | GFP_KERNEL); |
466 | if (!speed) |
467 | return -ENOMEM; |
468 | p = NULL; |
469 | for (i = 0; i < fan_data->num_speed; i++) { |
470 | p = of_prop_next_u32(prop, cur: p, pu: &u); |
471 | if (!p) |
472 | return -ENODEV; |
473 | speed[i].rpm = u; |
474 | p = of_prop_next_u32(prop, cur: p, pu: &u); |
475 | if (!p) |
476 | return -ENODEV; |
477 | speed[i].ctrl_val = u; |
478 | } |
479 | fan_data->speed = speed; |
480 | |
481 | return 0; |
482 | } |
483 | |
484 | static const struct of_device_id of_gpio_fan_match[] = { |
485 | { .compatible = "gpio-fan" , }, |
486 | {}, |
487 | }; |
488 | MODULE_DEVICE_TABLE(of, of_gpio_fan_match); |
489 | |
490 | static void gpio_fan_stop(void *data) |
491 | { |
492 | set_fan_speed(fan_data: data, speed_index: 0); |
493 | } |
494 | |
495 | static int gpio_fan_probe(struct platform_device *pdev) |
496 | { |
497 | int err; |
498 | struct gpio_fan_data *fan_data; |
499 | struct device *dev = &pdev->dev; |
500 | struct device_node *np = dev->of_node; |
501 | |
502 | fan_data = devm_kzalloc(dev, size: sizeof(struct gpio_fan_data), |
503 | GFP_KERNEL); |
504 | if (!fan_data) |
505 | return -ENOMEM; |
506 | |
507 | fan_data->dev = dev; |
508 | err = gpio_fan_get_of_data(fan_data); |
509 | if (err) |
510 | return err; |
511 | |
512 | platform_set_drvdata(pdev, data: fan_data); |
513 | mutex_init(&fan_data->lock); |
514 | |
515 | /* Configure control GPIOs if available. */ |
516 | if (fan_data->gpios && fan_data->num_gpios > 0) { |
517 | if (!fan_data->speed || fan_data->num_speed <= 1) |
518 | return -EINVAL; |
519 | err = fan_ctrl_init(fan_data); |
520 | if (err) |
521 | return err; |
522 | err = devm_add_action_or_reset(dev, gpio_fan_stop, fan_data); |
523 | if (err) |
524 | return err; |
525 | } |
526 | |
527 | /* Make this driver part of hwmon class. */ |
528 | fan_data->hwmon_dev = |
529 | devm_hwmon_device_register_with_groups(dev, |
530 | name: "gpio_fan" , drvdata: fan_data, |
531 | groups: gpio_fan_groups); |
532 | if (IS_ERR(ptr: fan_data->hwmon_dev)) |
533 | return PTR_ERR(ptr: fan_data->hwmon_dev); |
534 | |
535 | /* Configure alarm GPIO if available. */ |
536 | if (fan_data->alarm_gpio) { |
537 | err = fan_alarm_init(fan_data); |
538 | if (err) |
539 | return err; |
540 | } |
541 | |
542 | /* Optional cooling device register for Device tree platforms */ |
543 | fan_data->cdev = devm_thermal_of_cooling_device_register(dev, np, |
544 | type: "gpio-fan" , devdata: fan_data, ops: &gpio_fan_cool_ops); |
545 | |
546 | dev_info(dev, "GPIO fan initialized\n" ); |
547 | |
548 | return 0; |
549 | } |
550 | |
551 | static void gpio_fan_shutdown(struct platform_device *pdev) |
552 | { |
553 | struct gpio_fan_data *fan_data = platform_get_drvdata(pdev); |
554 | |
555 | if (fan_data->gpios) |
556 | set_fan_speed(fan_data, speed_index: 0); |
557 | } |
558 | |
559 | static int gpio_fan_suspend(struct device *dev) |
560 | { |
561 | struct gpio_fan_data *fan_data = dev_get_drvdata(dev); |
562 | |
563 | if (fan_data->gpios) { |
564 | fan_data->resume_speed = fan_data->speed_index; |
565 | set_fan_speed(fan_data, speed_index: 0); |
566 | } |
567 | |
568 | return 0; |
569 | } |
570 | |
571 | static int gpio_fan_resume(struct device *dev) |
572 | { |
573 | struct gpio_fan_data *fan_data = dev_get_drvdata(dev); |
574 | |
575 | if (fan_data->gpios) |
576 | set_fan_speed(fan_data, speed_index: fan_data->resume_speed); |
577 | |
578 | return 0; |
579 | } |
580 | |
581 | static DEFINE_SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume); |
582 | |
583 | static struct platform_driver gpio_fan_driver = { |
584 | .probe = gpio_fan_probe, |
585 | .shutdown = gpio_fan_shutdown, |
586 | .driver = { |
587 | .name = "gpio-fan" , |
588 | .pm = pm_sleep_ptr(&gpio_fan_pm), |
589 | .of_match_table = of_gpio_fan_match, |
590 | }, |
591 | }; |
592 | |
593 | module_platform_driver(gpio_fan_driver); |
594 | |
595 | MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>" ); |
596 | MODULE_DESCRIPTION("GPIO FAN driver" ); |
597 | MODULE_LICENSE("GPL" ); |
598 | MODULE_ALIAS("platform:gpio-fan" ); |
599 | |