1/*
2 * gpio-fan.c - Hwmon driver for fans connected to GPIO lines.
3 *
4 * Copyright (C) 2010 LaCie
5 *
6 * Author: Simon Guinot <sguinot@lacie.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 */
22
23#include <linux/module.h>
24#include <linux/init.h>
25#include <linux/slab.h>
26#include <linux/interrupt.h>
27#include <linux/irq.h>
28#include <linux/platform_device.h>
29#include <linux/err.h>
30#include <linux/mutex.h>
31#include <linux/hwmon.h>
32#include <linux/gpio/consumer.h>
33#include <linux/of.h>
34#include <linux/of_platform.h>
35#include <linux/thermal.h>
36
37struct gpio_fan_speed {
38 int rpm;
39 int ctrl_val;
40};
41
42struct gpio_fan_data {
43 struct device *dev;
44 struct device *hwmon_dev;
45 /* Cooling device if any */
46 struct thermal_cooling_device *cdev;
47 struct mutex lock; /* lock GPIOs operations. */
48 int num_gpios;
49 struct gpio_desc **gpios;
50 int num_speed;
51 struct gpio_fan_speed *speed;
52 int speed_index;
53#ifdef CONFIG_PM_SLEEP
54 int resume_speed;
55#endif
56 bool pwm_enable;
57 struct gpio_desc *alarm_gpio;
58 struct work_struct alarm_work;
59};
60
61/*
62 * Alarm GPIO.
63 */
64
65static void fan_alarm_notify(struct work_struct *ws)
66{
67 struct gpio_fan_data *fan_data =
68 container_of(ws, struct gpio_fan_data, alarm_work);
69
70 sysfs_notify(&fan_data->dev->kobj, NULL, "fan1_alarm");
71 kobject_uevent(&fan_data->dev->kobj, KOBJ_CHANGE);
72}
73
74static irqreturn_t fan_alarm_irq_handler(int irq, void *dev_id)
75{
76 struct gpio_fan_data *fan_data = dev_id;
77
78 schedule_work(&fan_data->alarm_work);
79
80 return IRQ_NONE;
81}
82
83static ssize_t fan1_alarm_show(struct device *dev,
84 struct device_attribute *attr, char *buf)
85{
86 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
87
88 return sprintf(buf, "%d\n",
89 gpiod_get_value_cansleep(fan_data->alarm_gpio));
90}
91
92static DEVICE_ATTR_RO(fan1_alarm);
93
94static int fan_alarm_init(struct gpio_fan_data *fan_data)
95{
96 int alarm_irq;
97 struct device *dev = fan_data->dev;
98
99 /*
100 * If the alarm GPIO don't support interrupts, just leave
101 * without initializing the fail notification support.
102 */
103 alarm_irq = gpiod_to_irq(fan_data->alarm_gpio);
104 if (alarm_irq <= 0)
105 return 0;
106
107 INIT_WORK(&fan_data->alarm_work, fan_alarm_notify);
108 irq_set_irq_type(alarm_irq, IRQ_TYPE_EDGE_BOTH);
109 return devm_request_irq(dev, alarm_irq, fan_alarm_irq_handler,
110 IRQF_SHARED, "GPIO fan alarm", fan_data);
111}
112
113/*
114 * Control GPIOs.
115 */
116
117/* Must be called with fan_data->lock held, except during initialization. */
118static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val)
119{
120 int i;
121
122 for (i = 0; i < fan_data->num_gpios; i++)
123 gpiod_set_value_cansleep(fan_data->gpios[i],
124 (ctrl_val >> i) & 1);
125}
126
127static int __get_fan_ctrl(struct gpio_fan_data *fan_data)
128{
129 int i;
130 int ctrl_val = 0;
131
132 for (i = 0; i < fan_data->num_gpios; i++) {
133 int value;
134
135 value = gpiod_get_value_cansleep(fan_data->gpios[i]);
136 ctrl_val |= (value << i);
137 }
138 return ctrl_val;
139}
140
141/* Must be called with fan_data->lock held, except during initialization. */
142static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index)
143{
144 if (fan_data->speed_index == speed_index)
145 return;
146
147 __set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val);
148 fan_data->speed_index = speed_index;
149}
150
151static int get_fan_speed_index(struct gpio_fan_data *fan_data)
152{
153 int ctrl_val = __get_fan_ctrl(fan_data);
154 int i;
155
156 for (i = 0; i < fan_data->num_speed; i++)
157 if (fan_data->speed[i].ctrl_val == ctrl_val)
158 return i;
159
160 dev_warn(fan_data->dev,
161 "missing speed array entry for GPIO value 0x%x\n", ctrl_val);
162
163 return -ENODEV;
164}
165
166static int rpm_to_speed_index(struct gpio_fan_data *fan_data, unsigned long rpm)
167{
168 struct gpio_fan_speed *speed = fan_data->speed;
169 int i;
170
171 for (i = 0; i < fan_data->num_speed; i++)
172 if (speed[i].rpm >= rpm)
173 return i;
174
175 return fan_data->num_speed - 1;
176}
177
178static ssize_t pwm1_show(struct device *dev, struct device_attribute *attr,
179 char *buf)
180{
181 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
182 u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1);
183
184 return sprintf(buf, "%d\n", pwm);
185}
186
187static ssize_t pwm1_store(struct device *dev, struct device_attribute *attr,
188 const char *buf, size_t count)
189{
190 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
191 unsigned long pwm;
192 int speed_index;
193 int ret = count;
194
195 if (kstrtoul(buf, 10, &pwm) || pwm > 255)
196 return -EINVAL;
197
198 mutex_lock(&fan_data->lock);
199
200 if (!fan_data->pwm_enable) {
201 ret = -EPERM;
202 goto exit_unlock;
203 }
204
205 speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255);
206 set_fan_speed(fan_data, speed_index);
207
208exit_unlock:
209 mutex_unlock(&fan_data->lock);
210
211 return ret;
212}
213
214static ssize_t pwm1_enable_show(struct device *dev,
215 struct device_attribute *attr, char *buf)
216{
217 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
218
219 return sprintf(buf, "%d\n", fan_data->pwm_enable);
220}
221
222static ssize_t pwm1_enable_store(struct device *dev,
223 struct device_attribute *attr,
224 const char *buf, size_t count)
225{
226 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
227 unsigned long val;
228
229 if (kstrtoul(buf, 10, &val) || val > 1)
230 return -EINVAL;
231
232 if (fan_data->pwm_enable == val)
233 return count;
234
235 mutex_lock(&fan_data->lock);
236
237 fan_data->pwm_enable = val;
238
239 /* Disable manual control mode: set fan at full speed. */
240 if (val == 0)
241 set_fan_speed(fan_data, fan_data->num_speed - 1);
242
243 mutex_unlock(&fan_data->lock);
244
245 return count;
246}
247
248static ssize_t pwm1_mode_show(struct device *dev,
249 struct device_attribute *attr, char *buf)
250{
251 return sprintf(buf, "0\n");
252}
253
254static ssize_t fan1_min_show(struct device *dev,
255 struct device_attribute *attr, char *buf)
256{
257 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
258
259 return sprintf(buf, "%d\n", fan_data->speed[0].rpm);
260}
261
262static ssize_t fan1_max_show(struct device *dev,
263 struct device_attribute *attr, char *buf)
264{
265 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
266
267 return sprintf(buf, "%d\n",
268 fan_data->speed[fan_data->num_speed - 1].rpm);
269}
270
271static ssize_t fan1_input_show(struct device *dev,
272 struct device_attribute *attr, char *buf)
273{
274 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
275
276 return sprintf(buf, "%d\n", fan_data->speed[fan_data->speed_index].rpm);
277}
278
279static ssize_t set_rpm(struct device *dev, struct device_attribute *attr,
280 const char *buf, size_t count)
281{
282 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
283 unsigned long rpm;
284 int ret = count;
285
286 if (kstrtoul(buf, 10, &rpm))
287 return -EINVAL;
288
289 mutex_lock(&fan_data->lock);
290
291 if (!fan_data->pwm_enable) {
292 ret = -EPERM;
293 goto exit_unlock;
294 }
295
296 set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm));
297
298exit_unlock:
299 mutex_unlock(&fan_data->lock);
300
301 return ret;
302}
303
304static DEVICE_ATTR_RW(pwm1);
305static DEVICE_ATTR_RW(pwm1_enable);
306static DEVICE_ATTR_RO(pwm1_mode);
307static DEVICE_ATTR_RO(fan1_min);
308static DEVICE_ATTR_RO(fan1_max);
309static DEVICE_ATTR_RO(fan1_input);
310static DEVICE_ATTR(fan1_target, 0644, fan1_input_show, set_rpm);
311
312static umode_t gpio_fan_is_visible(struct kobject *kobj,
313 struct attribute *attr, int index)
314{
315 struct device *dev = container_of(kobj, struct device, kobj);
316 struct gpio_fan_data *data = dev_get_drvdata(dev);
317
318 if (index == 0 && !data->alarm_gpio)
319 return 0;
320 if (index > 0 && !data->gpios)
321 return 0;
322
323 return attr->mode;
324}
325
326static struct attribute *gpio_fan_attributes[] = {
327 &dev_attr_fan1_alarm.attr, /* 0 */
328 &dev_attr_pwm1.attr, /* 1 */
329 &dev_attr_pwm1_enable.attr,
330 &dev_attr_pwm1_mode.attr,
331 &dev_attr_fan1_input.attr,
332 &dev_attr_fan1_target.attr,
333 &dev_attr_fan1_min.attr,
334 &dev_attr_fan1_max.attr,
335 NULL
336};
337
338static const struct attribute_group gpio_fan_group = {
339 .attrs = gpio_fan_attributes,
340 .is_visible = gpio_fan_is_visible,
341};
342
343static const struct attribute_group *gpio_fan_groups[] = {
344 &gpio_fan_group,
345 NULL
346};
347
348static int fan_ctrl_init(struct gpio_fan_data *fan_data)
349{
350 int num_gpios = fan_data->num_gpios;
351 struct gpio_desc **gpios = fan_data->gpios;
352 int i, err;
353
354 for (i = 0; i < num_gpios; i++) {
355 /*
356 * The GPIO descriptors were retrieved with GPIOD_ASIS so here
357 * we set the GPIO into output mode, carefully preserving the
358 * current value by setting it to whatever it is already set
359 * (no surprise changes in default fan speed).
360 */
361 err = gpiod_direction_output(gpios[i],
362 gpiod_get_value_cansleep(gpios[i]));
363 if (err)
364 return err;
365 }
366
367 fan_data->pwm_enable = true; /* Enable manual fan speed control. */
368 fan_data->speed_index = get_fan_speed_index(fan_data);
369 if (fan_data->speed_index < 0)
370 return fan_data->speed_index;
371
372 return 0;
373}
374
375static int gpio_fan_get_max_state(struct thermal_cooling_device *cdev,
376 unsigned long *state)
377{
378 struct gpio_fan_data *fan_data = cdev->devdata;
379
380 if (!fan_data)
381 return -EINVAL;
382
383 *state = fan_data->num_speed - 1;
384 return 0;
385}
386
387static int gpio_fan_get_cur_state(struct thermal_cooling_device *cdev,
388 unsigned long *state)
389{
390 struct gpio_fan_data *fan_data = cdev->devdata;
391
392 if (!fan_data)
393 return -EINVAL;
394
395 *state = fan_data->speed_index;
396 return 0;
397}
398
399static int gpio_fan_set_cur_state(struct thermal_cooling_device *cdev,
400 unsigned long state)
401{
402 struct gpio_fan_data *fan_data = cdev->devdata;
403
404 if (!fan_data)
405 return -EINVAL;
406
407 set_fan_speed(fan_data, state);
408 return 0;
409}
410
411static const struct thermal_cooling_device_ops gpio_fan_cool_ops = {
412 .get_max_state = gpio_fan_get_max_state,
413 .get_cur_state = gpio_fan_get_cur_state,
414 .set_cur_state = gpio_fan_set_cur_state,
415};
416
417/*
418 * Translate OpenFirmware node properties into platform_data
419 */
420static int gpio_fan_get_of_data(struct gpio_fan_data *fan_data)
421{
422 struct gpio_fan_speed *speed;
423 struct device *dev = fan_data->dev;
424 struct device_node *np = dev->of_node;
425 struct gpio_desc **gpios;
426 unsigned i;
427 u32 u;
428 struct property *prop;
429 const __be32 *p;
430
431 /* Alarm GPIO if one exists */
432 fan_data->alarm_gpio = devm_gpiod_get_optional(dev, "alarm", GPIOD_IN);
433 if (IS_ERR(fan_data->alarm_gpio))
434 return PTR_ERR(fan_data->alarm_gpio);
435
436 /* Fill GPIO pin array */
437 fan_data->num_gpios = gpiod_count(dev, NULL);
438 if (fan_data->num_gpios <= 0) {
439 if (fan_data->alarm_gpio)
440 return 0;
441 dev_err(dev, "DT properties empty / missing");
442 return -ENODEV;
443 }
444 gpios = devm_kcalloc(dev,
445 fan_data->num_gpios, sizeof(struct gpio_desc *),
446 GFP_KERNEL);
447 if (!gpios)
448 return -ENOMEM;
449 for (i = 0; i < fan_data->num_gpios; i++) {
450 gpios[i] = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS);
451 if (IS_ERR(gpios[i]))
452 return PTR_ERR(gpios[i]);
453 }
454 fan_data->gpios = gpios;
455
456 /* Get number of RPM/ctrl_val pairs in speed map */
457 prop = of_find_property(np, "gpio-fan,speed-map", &i);
458 if (!prop) {
459 dev_err(dev, "gpio-fan,speed-map DT property missing");
460 return -ENODEV;
461 }
462 i = i / sizeof(u32);
463 if (i == 0 || i & 1) {
464 dev_err(dev, "gpio-fan,speed-map contains zero/odd number of entries");
465 return -ENODEV;
466 }
467 fan_data->num_speed = i / 2;
468
469 /*
470 * Populate speed map
471 * Speed map is in the form <RPM ctrl_val RPM ctrl_val ...>
472 * this needs splitting into pairs to create gpio_fan_speed structs
473 */
474 speed = devm_kcalloc(dev,
475 fan_data->num_speed, sizeof(struct gpio_fan_speed),
476 GFP_KERNEL);
477 if (!speed)
478 return -ENOMEM;
479 p = NULL;
480 for (i = 0; i < fan_data->num_speed; i++) {
481 p = of_prop_next_u32(prop, p, &u);
482 if (!p)
483 return -ENODEV;
484 speed[i].rpm = u;
485 p = of_prop_next_u32(prop, p, &u);
486 if (!p)
487 return -ENODEV;
488 speed[i].ctrl_val = u;
489 }
490 fan_data->speed = speed;
491
492 return 0;
493}
494
495static const struct of_device_id of_gpio_fan_match[] = {
496 { .compatible = "gpio-fan", },
497 {},
498};
499MODULE_DEVICE_TABLE(of, of_gpio_fan_match);
500
501static int gpio_fan_probe(struct platform_device *pdev)
502{
503 int err;
504 struct gpio_fan_data *fan_data;
505 struct device *dev = &pdev->dev;
506 struct device_node *np = dev->of_node;
507
508 fan_data = devm_kzalloc(dev, sizeof(struct gpio_fan_data),
509 GFP_KERNEL);
510 if (!fan_data)
511 return -ENOMEM;
512
513 fan_data->dev = dev;
514 err = gpio_fan_get_of_data(fan_data);
515 if (err)
516 return err;
517
518 platform_set_drvdata(pdev, fan_data);
519 mutex_init(&fan_data->lock);
520
521 /* Configure alarm GPIO if available. */
522 if (fan_data->alarm_gpio) {
523 err = fan_alarm_init(fan_data);
524 if (err)
525 return err;
526 }
527
528 /* Configure control GPIOs if available. */
529 if (fan_data->gpios && fan_data->num_gpios > 0) {
530 if (!fan_data->speed || fan_data->num_speed <= 1)
531 return -EINVAL;
532 err = fan_ctrl_init(fan_data);
533 if (err)
534 return err;
535 }
536
537 /* Make this driver part of hwmon class. */
538 fan_data->hwmon_dev =
539 devm_hwmon_device_register_with_groups(dev,
540 "gpio_fan", fan_data,
541 gpio_fan_groups);
542 if (IS_ERR(fan_data->hwmon_dev))
543 return PTR_ERR(fan_data->hwmon_dev);
544
545 /* Optional cooling device register for Device tree platforms */
546 fan_data->cdev = thermal_of_cooling_device_register(np,
547 "gpio-fan",
548 fan_data,
549 &gpio_fan_cool_ops);
550
551 dev_info(dev, "GPIO fan initialized\n");
552
553 return 0;
554}
555
556static int gpio_fan_remove(struct platform_device *pdev)
557{
558 struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);
559
560 if (!IS_ERR(fan_data->cdev))
561 thermal_cooling_device_unregister(fan_data->cdev);
562
563 if (fan_data->gpios)
564 set_fan_speed(fan_data, 0);
565
566 return 0;
567}
568
569static void gpio_fan_shutdown(struct platform_device *pdev)
570{
571 gpio_fan_remove(pdev);
572}
573
574#ifdef CONFIG_PM_SLEEP
575static int gpio_fan_suspend(struct device *dev)
576{
577 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
578
579 if (fan_data->gpios) {
580 fan_data->resume_speed = fan_data->speed_index;
581 set_fan_speed(fan_data, 0);
582 }
583
584 return 0;
585}
586
587static int gpio_fan_resume(struct device *dev)
588{
589 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
590
591 if (fan_data->gpios)
592 set_fan_speed(fan_data, fan_data->resume_speed);
593
594 return 0;
595}
596
597static SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume);
598#define GPIO_FAN_PM (&gpio_fan_pm)
599#else
600#define GPIO_FAN_PM NULL
601#endif
602
603static struct platform_driver gpio_fan_driver = {
604 .probe = gpio_fan_probe,
605 .remove = gpio_fan_remove,
606 .shutdown = gpio_fan_shutdown,
607 .driver = {
608 .name = "gpio-fan",
609 .pm = GPIO_FAN_PM,
610 .of_match_table = of_match_ptr(of_gpio_fan_match),
611 },
612};
613
614module_platform_driver(gpio_fan_driver);
615
616MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
617MODULE_DESCRIPTION("GPIO FAN driver");
618MODULE_LICENSE("GPL");
619MODULE_ALIAS("platform:gpio-fan");
620