2 * gpio-fan.c - Hwmon driver for fans connected to GPIO lines.
4 * Copyright (C) 2010 LaCie
6 * Author: Simon Guinot <sguinot@lacie.com>
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.
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.
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
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.h>
33 #include <linux/gpio-fan.h>
35 #include <linux/of_platform.h>
36 #include <linux/of_gpio.h>
37 #include <linux/thermal.h>
39 struct gpio_fan_data {
40 struct platform_device *pdev;
41 struct device *hwmon_dev;
42 /* Cooling device if any */
43 struct thermal_cooling_device *cdev;
44 struct mutex lock; /* lock GPIOs operations. */
48 struct gpio_fan_speed *speed;
50 #ifdef CONFIG_PM_SLEEP
54 struct gpio_fan_alarm *alarm;
55 struct work_struct alarm_work;
62 static void fan_alarm_notify(struct work_struct *ws)
64 struct gpio_fan_data *fan_data =
65 container_of(ws, struct gpio_fan_data, alarm_work);
67 sysfs_notify(&fan_data->pdev->dev.kobj, NULL, "fan1_alarm");
68 kobject_uevent(&fan_data->pdev->dev.kobj, KOBJ_CHANGE);
71 static irqreturn_t fan_alarm_irq_handler(int irq, void *dev_id)
73 struct gpio_fan_data *fan_data = dev_id;
75 schedule_work(&fan_data->alarm_work);
80 static ssize_t show_fan_alarm(struct device *dev,
81 struct device_attribute *attr, char *buf)
83 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
84 struct gpio_fan_alarm *alarm = fan_data->alarm;
85 int value = gpio_get_value_cansleep(alarm->gpio);
87 if (alarm->active_low)
90 return sprintf(buf, "%d\n", value);
93 static DEVICE_ATTR(fan1_alarm, S_IRUGO, show_fan_alarm, NULL);
95 static int fan_alarm_init(struct gpio_fan_data *fan_data,
96 struct gpio_fan_alarm *alarm)
100 struct platform_device *pdev = fan_data->pdev;
102 fan_data->alarm = alarm;
104 err = devm_gpio_request(&pdev->dev, alarm->gpio, "GPIO fan alarm");
108 err = gpio_direction_input(alarm->gpio);
113 * If the alarm GPIO don't support interrupts, just leave
114 * without initializing the fail notification support.
116 alarm_irq = gpio_to_irq(alarm->gpio);
120 INIT_WORK(&fan_data->alarm_work, fan_alarm_notify);
121 irq_set_irq_type(alarm_irq, IRQ_TYPE_EDGE_BOTH);
122 err = devm_request_irq(&pdev->dev, alarm_irq, fan_alarm_irq_handler,
123 IRQF_SHARED, "GPIO fan alarm", fan_data);
131 /* Must be called with fan_data->lock held, except during initialization. */
132 static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val)
136 for (i = 0; i < fan_data->num_ctrl; i++)
137 gpio_set_value_cansleep(fan_data->ctrl[i], (ctrl_val >> i) & 1);
140 static int __get_fan_ctrl(struct gpio_fan_data *fan_data)
145 for (i = 0; i < fan_data->num_ctrl; i++) {
148 value = gpio_get_value_cansleep(fan_data->ctrl[i]);
149 ctrl_val |= (value << i);
154 /* Must be called with fan_data->lock held, except during initialization. */
155 static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index)
157 if (fan_data->speed_index == speed_index)
160 __set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val);
161 fan_data->speed_index = speed_index;
164 static int get_fan_speed_index(struct gpio_fan_data *fan_data)
166 int ctrl_val = __get_fan_ctrl(fan_data);
169 for (i = 0; i < fan_data->num_speed; i++)
170 if (fan_data->speed[i].ctrl_val == ctrl_val)
173 dev_warn(&fan_data->pdev->dev,
174 "missing speed array entry for GPIO value 0x%x\n", ctrl_val);
179 static int rpm_to_speed_index(struct gpio_fan_data *fan_data, unsigned long rpm)
181 struct gpio_fan_speed *speed = fan_data->speed;
184 for (i = 0; i < fan_data->num_speed; i++)
185 if (speed[i].rpm >= rpm)
188 return fan_data->num_speed - 1;
191 static ssize_t show_pwm(struct device *dev,
192 struct device_attribute *attr, char *buf)
194 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
195 u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1);
197 return sprintf(buf, "%d\n", pwm);
200 static ssize_t set_pwm(struct device *dev, struct device_attribute *attr,
201 const char *buf, size_t count)
203 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
208 if (kstrtoul(buf, 10, &pwm) || pwm > 255)
211 mutex_lock(&fan_data->lock);
213 if (!fan_data->pwm_enable) {
218 speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255);
219 set_fan_speed(fan_data, speed_index);
222 mutex_unlock(&fan_data->lock);
227 static ssize_t show_pwm_enable(struct device *dev,
228 struct device_attribute *attr, char *buf)
230 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
232 return sprintf(buf, "%d\n", fan_data->pwm_enable);
235 static ssize_t set_pwm_enable(struct device *dev, struct device_attribute *attr,
236 const char *buf, size_t count)
238 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
241 if (kstrtoul(buf, 10, &val) || val > 1)
244 if (fan_data->pwm_enable == val)
247 mutex_lock(&fan_data->lock);
249 fan_data->pwm_enable = val;
251 /* Disable manual control mode: set fan at full speed. */
253 set_fan_speed(fan_data, fan_data->num_speed - 1);
255 mutex_unlock(&fan_data->lock);
260 static ssize_t show_pwm_mode(struct device *dev,
261 struct device_attribute *attr, char *buf)
263 return sprintf(buf, "0\n");
266 static ssize_t show_rpm_min(struct device *dev,
267 struct device_attribute *attr, char *buf)
269 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
271 return sprintf(buf, "%d\n", fan_data->speed[0].rpm);
274 static ssize_t show_rpm_max(struct device *dev,
275 struct device_attribute *attr, char *buf)
277 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
279 return sprintf(buf, "%d\n",
280 fan_data->speed[fan_data->num_speed - 1].rpm);
283 static ssize_t show_rpm(struct device *dev,
284 struct device_attribute *attr, char *buf)
286 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
288 return sprintf(buf, "%d\n", fan_data->speed[fan_data->speed_index].rpm);
291 static ssize_t set_rpm(struct device *dev, struct device_attribute *attr,
292 const char *buf, size_t count)
294 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
298 if (kstrtoul(buf, 10, &rpm))
301 mutex_lock(&fan_data->lock);
303 if (!fan_data->pwm_enable) {
308 set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm));
311 mutex_unlock(&fan_data->lock);
316 static DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm, set_pwm);
317 static DEVICE_ATTR(pwm1_enable, S_IRUGO | S_IWUSR,
318 show_pwm_enable, set_pwm_enable);
319 static DEVICE_ATTR(pwm1_mode, S_IRUGO, show_pwm_mode, NULL);
320 static DEVICE_ATTR(fan1_min, S_IRUGO, show_rpm_min, NULL);
321 static DEVICE_ATTR(fan1_max, S_IRUGO, show_rpm_max, NULL);
322 static DEVICE_ATTR(fan1_input, S_IRUGO, show_rpm, NULL);
323 static DEVICE_ATTR(fan1_target, S_IRUGO | S_IWUSR, show_rpm, set_rpm);
325 static umode_t gpio_fan_is_visible(struct kobject *kobj,
326 struct attribute *attr, int index)
328 struct device *dev = container_of(kobj, struct device, kobj);
329 struct gpio_fan_data *data = dev_get_drvdata(dev);
331 if (index == 0 && !data->alarm)
333 if (index > 0 && !data->ctrl)
339 static struct attribute *gpio_fan_attributes[] = {
340 &dev_attr_fan1_alarm.attr, /* 0 */
341 &dev_attr_pwm1.attr, /* 1 */
342 &dev_attr_pwm1_enable.attr,
343 &dev_attr_pwm1_mode.attr,
344 &dev_attr_fan1_input.attr,
345 &dev_attr_fan1_target.attr,
346 &dev_attr_fan1_min.attr,
347 &dev_attr_fan1_max.attr,
351 static const struct attribute_group gpio_fan_group = {
352 .attrs = gpio_fan_attributes,
353 .is_visible = gpio_fan_is_visible,
356 static const struct attribute_group *gpio_fan_groups[] = {
361 static int fan_ctrl_init(struct gpio_fan_data *fan_data,
362 struct gpio_fan_platform_data *pdata)
364 struct platform_device *pdev = fan_data->pdev;
365 int num_ctrl = pdata->num_ctrl;
366 unsigned *ctrl = pdata->ctrl;
369 for (i = 0; i < num_ctrl; i++) {
370 err = devm_gpio_request(&pdev->dev, ctrl[i],
375 err = gpio_direction_output(ctrl[i],
376 gpio_get_value_cansleep(ctrl[i]));
381 fan_data->num_ctrl = num_ctrl;
382 fan_data->ctrl = ctrl;
383 fan_data->num_speed = pdata->num_speed;
384 fan_data->speed = pdata->speed;
385 fan_data->pwm_enable = true; /* Enable manual fan speed control. */
386 fan_data->speed_index = get_fan_speed_index(fan_data);
387 if (fan_data->speed_index < 0)
388 return fan_data->speed_index;
393 static int gpio_fan_get_max_state(struct thermal_cooling_device *cdev,
394 unsigned long *state)
396 struct gpio_fan_data *fan_data = cdev->devdata;
401 *state = fan_data->num_speed - 1;
405 static int gpio_fan_get_cur_state(struct thermal_cooling_device *cdev,
406 unsigned long *state)
408 struct gpio_fan_data *fan_data = cdev->devdata;
413 *state = fan_data->speed_index;
417 static int gpio_fan_set_cur_state(struct thermal_cooling_device *cdev,
420 struct gpio_fan_data *fan_data = cdev->devdata;
425 set_fan_speed(fan_data, state);
429 static const struct thermal_cooling_device_ops gpio_fan_cool_ops = {
430 .get_max_state = gpio_fan_get_max_state,
431 .get_cur_state = gpio_fan_get_cur_state,
432 .set_cur_state = gpio_fan_set_cur_state,
435 #ifdef CONFIG_OF_GPIO
437 * Translate OpenFirmware node properties into platform_data
439 static int gpio_fan_get_of_pdata(struct device *dev,
440 struct gpio_fan_platform_data *pdata)
442 struct device_node *node;
443 struct gpio_fan_speed *speed;
447 struct property *prop;
452 /* Alarm GPIO if one exists */
453 if (of_gpio_named_count(node, "alarm-gpios") > 0) {
454 struct gpio_fan_alarm *alarm;
456 enum of_gpio_flags flags;
458 alarm = devm_kzalloc(dev, sizeof(struct gpio_fan_alarm),
463 val = of_get_named_gpio_flags(node, "alarm-gpios", 0, &flags);
467 alarm->active_low = flags & OF_GPIO_ACTIVE_LOW;
469 pdata->alarm = alarm;
472 /* Fill GPIO pin array */
473 pdata->num_ctrl = of_gpio_count(node);
474 if (pdata->num_ctrl <= 0) {
477 dev_err(dev, "DT properties empty / missing");
480 ctrl = devm_kzalloc(dev, pdata->num_ctrl * sizeof(unsigned),
484 for (i = 0; i < pdata->num_ctrl; i++) {
487 val = of_get_gpio(node, i);
494 /* Get number of RPM/ctrl_val pairs in speed map */
495 prop = of_find_property(node, "gpio-fan,speed-map", &i);
497 dev_err(dev, "gpio-fan,speed-map DT property missing");
501 if (i == 0 || i & 1) {
502 dev_err(dev, "gpio-fan,speed-map contains zero/odd number of entries");
505 pdata->num_speed = i / 2;
509 * Speed map is in the form <RPM ctrl_val RPM ctrl_val ...>
510 * this needs splitting into pairs to create gpio_fan_speed structs
512 speed = devm_kzalloc(dev,
513 pdata->num_speed * sizeof(struct gpio_fan_speed),
518 for (i = 0; i < pdata->num_speed; i++) {
519 p = of_prop_next_u32(prop, p, &u);
523 p = of_prop_next_u32(prop, p, &u);
526 speed[i].ctrl_val = u;
528 pdata->speed = speed;
533 static const struct of_device_id of_gpio_fan_match[] = {
534 { .compatible = "gpio-fan", },
537 MODULE_DEVICE_TABLE(of, of_gpio_fan_match);
538 #endif /* CONFIG_OF_GPIO */
540 static int gpio_fan_probe(struct platform_device *pdev)
543 struct gpio_fan_data *fan_data;
544 struct gpio_fan_platform_data *pdata = dev_get_platdata(&pdev->dev);
546 fan_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_fan_data),
551 #ifdef CONFIG_OF_GPIO
553 pdata = devm_kzalloc(&pdev->dev,
554 sizeof(struct gpio_fan_platform_data),
559 err = gpio_fan_get_of_pdata(&pdev->dev, pdata);
563 #else /* CONFIG_OF_GPIO */
566 #endif /* CONFIG_OF_GPIO */
568 fan_data->pdev = pdev;
569 platform_set_drvdata(pdev, fan_data);
570 mutex_init(&fan_data->lock);
572 /* Configure alarm GPIO if available. */
574 err = fan_alarm_init(fan_data, pdata->alarm);
579 /* Configure control GPIOs if available. */
580 if (pdata->ctrl && pdata->num_ctrl > 0) {
581 if (!pdata->speed || pdata->num_speed <= 1)
583 err = fan_ctrl_init(fan_data, pdata);
588 /* Make this driver part of hwmon class. */
589 fan_data->hwmon_dev =
590 devm_hwmon_device_register_with_groups(&pdev->dev,
591 "gpio_fan", fan_data,
593 if (IS_ERR(fan_data->hwmon_dev))
594 return PTR_ERR(fan_data->hwmon_dev);
595 #ifdef CONFIG_OF_GPIO
596 /* Optional cooling device register for Device tree platforms */
597 fan_data->cdev = thermal_of_cooling_device_register(pdev->dev.of_node,
601 #else /* CONFIG_OF_GPIO */
602 /* Optional cooling device register for non Device tree platforms */
603 fan_data->cdev = thermal_cooling_device_register("gpio-fan", fan_data,
605 #endif /* CONFIG_OF_GPIO */
607 dev_info(&pdev->dev, "GPIO fan initialized\n");
612 static int gpio_fan_remove(struct platform_device *pdev)
614 struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);
616 if (!IS_ERR(fan_data->cdev))
617 thermal_cooling_device_unregister(fan_data->cdev);
620 set_fan_speed(fan_data, 0);
625 static void gpio_fan_shutdown(struct platform_device *pdev)
627 gpio_fan_remove(pdev);
630 #ifdef CONFIG_PM_SLEEP
631 static int gpio_fan_suspend(struct device *dev)
633 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
635 if (fan_data->ctrl) {
636 fan_data->resume_speed = fan_data->speed_index;
637 set_fan_speed(fan_data, 0);
643 static int gpio_fan_resume(struct device *dev)
645 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
648 set_fan_speed(fan_data, fan_data->resume_speed);
653 static SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume);
654 #define GPIO_FAN_PM (&gpio_fan_pm)
656 #define GPIO_FAN_PM NULL
659 static struct platform_driver gpio_fan_driver = {
660 .probe = gpio_fan_probe,
661 .remove = gpio_fan_remove,
662 .shutdown = gpio_fan_shutdown,
666 #ifdef CONFIG_OF_GPIO
667 .of_match_table = of_match_ptr(of_gpio_fan_match),
672 module_platform_driver(gpio_fan_driver);
674 MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
675 MODULE_DESCRIPTION("GPIO FAN driver");
676 MODULE_LICENSE("GPL");
677 MODULE_ALIAS("platform:gpio-fan");