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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
24struct gpio_fan_speed {
25 int rpm;
26 int ctrl_val;
27};
28
29struct gpio_fan_data {
30 struct device *dev;
31 struct device *hwmon_dev;
32
33 struct thermal_cooling_device *cdev;
34 struct mutex lock;
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
50
51
52static 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
61static 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
70static 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
79static DEVICE_ATTR_RO(fan1_alarm);
80
81static 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
88
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
102
103
104
105static 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
114static 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
129static 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
138static 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
153static 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
165static 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
174static 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
195exit_unlock:
196 mutex_unlock(&fan_data->lock);
197
198 return ret;
199}
200
201static 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
209static 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
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
235static ssize_t pwm1_mode_show(struct device *dev,
236 struct device_attribute *attr, char *buf)
237{
238 return sprintf(buf, "0\n");
239}
240
241static 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
249static 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
258static 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
266static 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
285exit_unlock:
286 mutex_unlock(&fan_data->lock);
287
288 return ret;
289}
290
291static DEVICE_ATTR_RW(pwm1);
292static DEVICE_ATTR_RW(pwm1_enable);
293static DEVICE_ATTR_RO(pwm1_mode);
294static DEVICE_ATTR_RO(fan1_min);
295static DEVICE_ATTR_RO(fan1_max);
296static DEVICE_ATTR_RO(fan1_input);
297static DEVICE_ATTR(fan1_target, 0644, fan1_input_show, set_rpm);
298
299static umode_t gpio_fan_is_visible(struct kobject *kobj,
300 struct attribute *attr, int index)
301{
302 struct device *dev = kobj_to_dev(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
313static struct attribute *gpio_fan_attributes[] = {
314 &dev_attr_fan1_alarm.attr,
315 &dev_attr_pwm1.attr,
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
325static const struct attribute_group gpio_fan_group = {
326 .attrs = gpio_fan_attributes,
327 .is_visible = gpio_fan_is_visible,
328};
329
330static const struct attribute_group *gpio_fan_groups[] = {
331 &gpio_fan_group,
332 NULL
333};
334
335static 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
344
345
346
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;
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
362static 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
374static 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
386static 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 set_fan_speed(fan_data, state);
395 return 0;
396}
397
398static const struct thermal_cooling_device_ops gpio_fan_cool_ops = {
399 .get_max_state = gpio_fan_get_max_state,
400 .get_cur_state = gpio_fan_get_cur_state,
401 .set_cur_state = gpio_fan_set_cur_state,
402};
403
404
405
406
407static int gpio_fan_get_of_data(struct gpio_fan_data *fan_data)
408{
409 struct gpio_fan_speed *speed;
410 struct device *dev = fan_data->dev;
411 struct device_node *np = dev->of_node;
412 struct gpio_desc **gpios;
413 unsigned i;
414 u32 u;
415 struct property *prop;
416 const __be32 *p;
417
418
419 fan_data->alarm_gpio = devm_gpiod_get_optional(dev, "alarm", GPIOD_IN);
420 if (IS_ERR(fan_data->alarm_gpio))
421 return PTR_ERR(fan_data->alarm_gpio);
422
423
424 fan_data->num_gpios = gpiod_count(dev, NULL);
425 if (fan_data->num_gpios <= 0) {
426 if (fan_data->alarm_gpio)
427 return 0;
428 dev_err(dev, "DT properties empty / missing");
429 return -ENODEV;
430 }
431 gpios = devm_kcalloc(dev,
432 fan_data->num_gpios, sizeof(struct gpio_desc *),
433 GFP_KERNEL);
434 if (!gpios)
435 return -ENOMEM;
436 for (i = 0; i < fan_data->num_gpios; i++) {
437 gpios[i] = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS);
438 if (IS_ERR(gpios[i]))
439 return PTR_ERR(gpios[i]);
440 }
441 fan_data->gpios = gpios;
442
443
444 prop = of_find_property(np, "gpio-fan,speed-map", &i);
445 if (!prop) {
446 dev_err(dev, "gpio-fan,speed-map DT property missing");
447 return -ENODEV;
448 }
449 i = i / sizeof(u32);
450 if (i == 0 || i & 1) {
451 dev_err(dev, "gpio-fan,speed-map contains zero/odd number of entries");
452 return -ENODEV;
453 }
454 fan_data->num_speed = i / 2;
455
456
457
458
459
460
461 speed = devm_kcalloc(dev,
462 fan_data->num_speed, sizeof(struct gpio_fan_speed),
463 GFP_KERNEL);
464 if (!speed)
465 return -ENOMEM;
466 p = NULL;
467 for (i = 0; i < fan_data->num_speed; i++) {
468 p = of_prop_next_u32(prop, p, &u);
469 if (!p)
470 return -ENODEV;
471 speed[i].rpm = u;
472 p = of_prop_next_u32(prop, p, &u);
473 if (!p)
474 return -ENODEV;
475 speed[i].ctrl_val = u;
476 }
477 fan_data->speed = speed;
478
479 return 0;
480}
481
482static const struct of_device_id of_gpio_fan_match[] = {
483 { .compatible = "gpio-fan", },
484 {},
485};
486MODULE_DEVICE_TABLE(of, of_gpio_fan_match);
487
488static void gpio_fan_stop(void *data)
489{
490 set_fan_speed(data, 0);
491}
492
493static int gpio_fan_probe(struct platform_device *pdev)
494{
495 int err;
496 struct gpio_fan_data *fan_data;
497 struct device *dev = &pdev->dev;
498 struct device_node *np = dev->of_node;
499
500 fan_data = devm_kzalloc(dev, sizeof(struct gpio_fan_data),
501 GFP_KERNEL);
502 if (!fan_data)
503 return -ENOMEM;
504
505 fan_data->dev = dev;
506 err = gpio_fan_get_of_data(fan_data);
507 if (err)
508 return err;
509
510 platform_set_drvdata(pdev, fan_data);
511 mutex_init(&fan_data->lock);
512
513
514 if (fan_data->gpios && fan_data->num_gpios > 0) {
515 if (!fan_data->speed || fan_data->num_speed <= 1)
516 return -EINVAL;
517 err = fan_ctrl_init(fan_data);
518 if (err)
519 return err;
520 err = devm_add_action_or_reset(dev, gpio_fan_stop, fan_data);
521 if (err)
522 return err;
523 }
524
525
526 fan_data->hwmon_dev =
527 devm_hwmon_device_register_with_groups(dev,
528 "gpio_fan", fan_data,
529 gpio_fan_groups);
530 if (IS_ERR(fan_data->hwmon_dev))
531 return PTR_ERR(fan_data->hwmon_dev);
532
533
534 if (fan_data->alarm_gpio) {
535 err = fan_alarm_init(fan_data);
536 if (err)
537 return err;
538 }
539
540
541 fan_data->cdev = devm_thermal_of_cooling_device_register(dev, np,
542 "gpio-fan", fan_data, &gpio_fan_cool_ops);
543
544 dev_info(dev, "GPIO fan initialized\n");
545
546 return 0;
547}
548
549static void gpio_fan_shutdown(struct platform_device *pdev)
550{
551 struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);
552
553 if (fan_data->gpios)
554 set_fan_speed(fan_data, 0);
555}
556
557#ifdef CONFIG_PM_SLEEP
558static 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
570static 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
580static SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume);
581#define GPIO_FAN_PM (&gpio_fan_pm)
582#else
583#define GPIO_FAN_PM NULL
584#endif
585
586static struct platform_driver gpio_fan_driver = {
587 .probe = gpio_fan_probe,
588 .shutdown = gpio_fan_shutdown,
589 .driver = {
590 .name = "gpio-fan",
591 .pm = GPIO_FAN_PM,
592 .of_match_table = of_match_ptr(of_gpio_fan_match),
593 },
594};
595
596module_platform_driver(gpio_fan_driver);
597
598MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
599MODULE_DESCRIPTION("GPIO FAN driver");
600MODULE_LICENSE("GPL");
601MODULE_ALIAS("platform:gpio-fan");
602
