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/consumer.h>
34 #include <linux/of_platform.h>
35 #include <linux/thermal.h>
37 struct gpio_fan_speed {
42 struct gpio_fan_data {
44 struct device *hwmon_dev;
45 /* Cooling device if any */
46 struct thermal_cooling_device *cdev;
47 struct mutex lock; /* lock GPIOs operations. */
49 struct gpio_desc **gpios;
51 struct gpio_fan_speed *speed;
53 #ifdef CONFIG_PM_SLEEP
57 struct gpio_desc *alarm_gpio;
58 struct work_struct alarm_work;
65 static void fan_alarm_notify(struct work_struct *ws)
67 struct gpio_fan_data *fan_data =
68 container_of(ws, struct gpio_fan_data, alarm_work);
70 sysfs_notify(&fan_data->dev->kobj, NULL, "fan1_alarm");
71 kobject_uevent(&fan_data->dev->kobj, KOBJ_CHANGE);
74 static irqreturn_t fan_alarm_irq_handler(int irq, void *dev_id)
76 struct gpio_fan_data *fan_data = dev_id;
78 schedule_work(&fan_data->alarm_work);
83 static ssize_t fan1_alarm_show(struct device *dev,
84 struct device_attribute *attr, char *buf)
86 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
88 return sprintf(buf, "%d\n",
89 gpiod_get_value_cansleep(fan_data->alarm_gpio));
92 static DEVICE_ATTR_RO(fan1_alarm);
94 static int fan_alarm_init(struct gpio_fan_data *fan_data)
97 struct device *dev = fan_data->dev;
100 * If the alarm GPIO don't support interrupts, just leave
101 * without initializing the fail notification support.
103 alarm_irq = gpiod_to_irq(fan_data->alarm_gpio);
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);
117 /* Must be called with fan_data->lock held, except during initialization. */
118 static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val)
122 for (i = 0; i < fan_data->num_gpios; i++)
123 gpiod_set_value_cansleep(fan_data->gpios[i],
124 (ctrl_val >> i) & 1);
127 static int __get_fan_ctrl(struct gpio_fan_data *fan_data)
132 for (i = 0; i < fan_data->num_gpios; i++) {
135 value = gpiod_get_value_cansleep(fan_data->gpios[i]);
136 ctrl_val |= (value << i);
141 /* Must be called with fan_data->lock held, except during initialization. */
142 static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index)
144 if (fan_data->speed_index == speed_index)
147 __set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val);
148 fan_data->speed_index = speed_index;
151 static int get_fan_speed_index(struct gpio_fan_data *fan_data)
153 int ctrl_val = __get_fan_ctrl(fan_data);
156 for (i = 0; i < fan_data->num_speed; i++)
157 if (fan_data->speed[i].ctrl_val == ctrl_val)
160 dev_warn(fan_data->dev,
161 "missing speed array entry for GPIO value 0x%x\n", ctrl_val);
166 static int rpm_to_speed_index(struct gpio_fan_data *fan_data, unsigned long rpm)
168 struct gpio_fan_speed *speed = fan_data->speed;
171 for (i = 0; i < fan_data->num_speed; i++)
172 if (speed[i].rpm >= rpm)
175 return fan_data->num_speed - 1;
178 static ssize_t pwm1_show(struct device *dev, struct device_attribute *attr,
181 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
182 u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1);
184 return sprintf(buf, "%d\n", pwm);
187 static ssize_t pwm1_store(struct device *dev, struct device_attribute *attr,
188 const char *buf, size_t count)
190 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
195 if (kstrtoul(buf, 10, &pwm) || pwm > 255)
198 mutex_lock(&fan_data->lock);
200 if (!fan_data->pwm_enable) {
205 speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255);
206 set_fan_speed(fan_data, speed_index);
209 mutex_unlock(&fan_data->lock);
214 static ssize_t pwm1_enable_show(struct device *dev,
215 struct device_attribute *attr, char *buf)
217 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
219 return sprintf(buf, "%d\n", fan_data->pwm_enable);
222 static ssize_t pwm1_enable_store(struct device *dev,
223 struct device_attribute *attr,
224 const char *buf, size_t count)
226 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
229 if (kstrtoul(buf, 10, &val) || val > 1)
232 if (fan_data->pwm_enable == val)
235 mutex_lock(&fan_data->lock);
237 fan_data->pwm_enable = val;
239 /* Disable manual control mode: set fan at full speed. */
241 set_fan_speed(fan_data, fan_data->num_speed - 1);
243 mutex_unlock(&fan_data->lock);
248 static ssize_t pwm1_mode_show(struct device *dev,
249 struct device_attribute *attr, char *buf)
251 return sprintf(buf, "0\n");
254 static ssize_t fan1_min_show(struct device *dev,
255 struct device_attribute *attr, char *buf)
257 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
259 return sprintf(buf, "%d\n", fan_data->speed[0].rpm);
262 static ssize_t fan1_max_show(struct device *dev,
263 struct device_attribute *attr, char *buf)
265 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
267 return sprintf(buf, "%d\n",
268 fan_data->speed[fan_data->num_speed - 1].rpm);
271 static ssize_t fan1_input_show(struct device *dev,
272 struct device_attribute *attr, char *buf)
274 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
276 return sprintf(buf, "%d\n", fan_data->speed[fan_data->speed_index].rpm);
279 static ssize_t set_rpm(struct device *dev, struct device_attribute *attr,
280 const char *buf, size_t count)
282 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
286 if (kstrtoul(buf, 10, &rpm))
289 mutex_lock(&fan_data->lock);
291 if (!fan_data->pwm_enable) {
296 set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm));
299 mutex_unlock(&fan_data->lock);
304 static DEVICE_ATTR_RW(pwm1);
305 static DEVICE_ATTR_RW(pwm1_enable);
306 static DEVICE_ATTR_RO(pwm1_mode);
307 static DEVICE_ATTR_RO(fan1_min);
308 static DEVICE_ATTR_RO(fan1_max);
309 static DEVICE_ATTR_RO(fan1_input);
310 static DEVICE_ATTR(fan1_target, S_IRUGO | S_IWUSR, fan1_input_show, set_rpm);
312 static umode_t gpio_fan_is_visible(struct kobject *kobj,
313 struct attribute *attr, int index)
315 struct device *dev = container_of(kobj, struct device, kobj);
316 struct gpio_fan_data *data = dev_get_drvdata(dev);
318 if (index == 0 && !data->alarm_gpio)
320 if (index > 0 && !data->gpios)
326 static 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,
338 static const struct attribute_group gpio_fan_group = {
339 .attrs = gpio_fan_attributes,
340 .is_visible = gpio_fan_is_visible,
343 static const struct attribute_group *gpio_fan_groups[] = {
348 static int fan_ctrl_init(struct gpio_fan_data *fan_data)
350 int num_gpios = fan_data->num_gpios;
351 struct gpio_desc **gpios = fan_data->gpios;
354 for (i = 0; i < num_gpios; i++) {
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).
361 err = gpiod_direction_output(gpios[i],
362 gpiod_get_value_cansleep(gpios[i]));
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;
375 static int gpio_fan_get_max_state(struct thermal_cooling_device *cdev,
376 unsigned long *state)
378 struct gpio_fan_data *fan_data = cdev->devdata;
383 *state = fan_data->num_speed - 1;
387 static int gpio_fan_get_cur_state(struct thermal_cooling_device *cdev,
388 unsigned long *state)
390 struct gpio_fan_data *fan_data = cdev->devdata;
395 *state = fan_data->speed_index;
399 static int gpio_fan_set_cur_state(struct thermal_cooling_device *cdev,
402 struct gpio_fan_data *fan_data = cdev->devdata;
407 if (state >= fan_data->num_speed)
410 set_fan_speed(fan_data, state);
414 static const struct thermal_cooling_device_ops gpio_fan_cool_ops = {
415 .get_max_state = gpio_fan_get_max_state,
416 .get_cur_state = gpio_fan_get_cur_state,
417 .set_cur_state = gpio_fan_set_cur_state,
421 * Translate OpenFirmware node properties into platform_data
423 static int gpio_fan_get_of_data(struct gpio_fan_data *fan_data)
425 struct gpio_fan_speed *speed;
426 struct device *dev = fan_data->dev;
427 struct device_node *np = dev->of_node;
428 struct gpio_desc **gpios;
431 struct property *prop;
434 /* Alarm GPIO if one exists */
435 fan_data->alarm_gpio = devm_gpiod_get_optional(dev, "alarm", GPIOD_IN);
436 if (IS_ERR(fan_data->alarm_gpio))
437 return PTR_ERR(fan_data->alarm_gpio);
439 /* Fill GPIO pin array */
440 fan_data->num_gpios = gpiod_count(dev, NULL);
441 if (fan_data->num_gpios <= 0) {
442 if (fan_data->alarm_gpio)
444 dev_err(dev, "DT properties empty / missing");
447 gpios = devm_kcalloc(dev,
448 fan_data->num_gpios, sizeof(struct gpio_desc *),
452 for (i = 0; i < fan_data->num_gpios; i++) {
453 gpios[i] = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS);
454 if (IS_ERR(gpios[i]))
455 return PTR_ERR(gpios[i]);
457 fan_data->gpios = gpios;
459 /* Get number of RPM/ctrl_val pairs in speed map */
460 prop = of_find_property(np, "gpio-fan,speed-map", &i);
462 dev_err(dev, "gpio-fan,speed-map DT property missing");
466 if (i == 0 || i & 1) {
467 dev_err(dev, "gpio-fan,speed-map contains zero/odd number of entries");
470 fan_data->num_speed = i / 2;
474 * Speed map is in the form <RPM ctrl_val RPM ctrl_val ...>
475 * this needs splitting into pairs to create gpio_fan_speed structs
477 speed = devm_kcalloc(dev,
478 fan_data->num_speed, sizeof(struct gpio_fan_speed),
483 for (i = 0; i < fan_data->num_speed; i++) {
484 p = of_prop_next_u32(prop, p, &u);
488 p = of_prop_next_u32(prop, p, &u);
491 speed[i].ctrl_val = u;
493 fan_data->speed = speed;
498 static const struct of_device_id of_gpio_fan_match[] = {
499 { .compatible = "gpio-fan", },
502 MODULE_DEVICE_TABLE(of, of_gpio_fan_match);
504 static int gpio_fan_probe(struct platform_device *pdev)
507 struct gpio_fan_data *fan_data;
508 struct device *dev = &pdev->dev;
509 struct device_node *np = dev->of_node;
511 fan_data = devm_kzalloc(dev, sizeof(struct gpio_fan_data),
517 err = gpio_fan_get_of_data(fan_data);
521 platform_set_drvdata(pdev, fan_data);
522 mutex_init(&fan_data->lock);
524 /* Configure alarm GPIO if available. */
525 if (fan_data->alarm_gpio) {
526 err = fan_alarm_init(fan_data);
531 /* Configure control GPIOs if available. */
532 if (fan_data->gpios && fan_data->num_gpios > 0) {
533 if (!fan_data->speed || fan_data->num_speed <= 1)
535 err = fan_ctrl_init(fan_data);
540 /* Make this driver part of hwmon class. */
541 fan_data->hwmon_dev =
542 devm_hwmon_device_register_with_groups(dev,
543 "gpio_fan", fan_data,
545 if (IS_ERR(fan_data->hwmon_dev))
546 return PTR_ERR(fan_data->hwmon_dev);
548 /* Optional cooling device register for Device tree platforms */
549 fan_data->cdev = thermal_of_cooling_device_register(np,
554 dev_info(dev, "GPIO fan initialized\n");
559 static int gpio_fan_remove(struct platform_device *pdev)
561 struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);
563 if (!IS_ERR(fan_data->cdev))
564 thermal_cooling_device_unregister(fan_data->cdev);
567 set_fan_speed(fan_data, 0);
572 static void gpio_fan_shutdown(struct platform_device *pdev)
574 gpio_fan_remove(pdev);
577 #ifdef CONFIG_PM_SLEEP
578 static int gpio_fan_suspend(struct device *dev)
580 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
582 if (fan_data->gpios) {
583 fan_data->resume_speed = fan_data->speed_index;
584 set_fan_speed(fan_data, 0);
590 static int gpio_fan_resume(struct device *dev)
592 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
595 set_fan_speed(fan_data, fan_data->resume_speed);
600 static SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume);
601 #define GPIO_FAN_PM (&gpio_fan_pm)
603 #define GPIO_FAN_PM NULL
606 static struct platform_driver gpio_fan_driver = {
607 .probe = gpio_fan_probe,
608 .remove = gpio_fan_remove,
609 .shutdown = gpio_fan_shutdown,
613 .of_match_table = of_match_ptr(of_gpio_fan_match),
617 module_platform_driver(gpio_fan_driver);
619 MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
620 MODULE_DESCRIPTION("GPIO FAN driver");
621 MODULE_LICENSE("GPL");
622 MODULE_ALIAS("platform:gpio-fan");