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>
34 #include <linux/of_platform.h>
35 #include <linux/of_gpio.h>
37 struct gpio_fan_data {
38 struct platform_device *pdev;
39 struct device *hwmon_dev;
40 struct mutex lock; /* lock GPIOs operations. */
44 struct gpio_fan_speed *speed;
46 #ifdef CONFIG_PM_SLEEP
50 struct gpio_fan_alarm *alarm;
51 struct work_struct alarm_work;
58 static void fan_alarm_notify(struct work_struct *ws)
60 struct gpio_fan_data *fan_data =
61 container_of(ws, struct gpio_fan_data, alarm_work);
63 sysfs_notify(&fan_data->pdev->dev.kobj, NULL, "fan1_alarm");
64 kobject_uevent(&fan_data->pdev->dev.kobj, KOBJ_CHANGE);
67 static irqreturn_t fan_alarm_irq_handler(int irq, void *dev_id)
69 struct gpio_fan_data *fan_data = dev_id;
71 schedule_work(&fan_data->alarm_work);
76 static ssize_t show_fan_alarm(struct device *dev,
77 struct device_attribute *attr, char *buf)
79 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
80 struct gpio_fan_alarm *alarm = fan_data->alarm;
81 int value = gpio_get_value(alarm->gpio);
83 if (alarm->active_low)
86 return sprintf(buf, "%d\n", value);
89 static DEVICE_ATTR(fan1_alarm, S_IRUGO, show_fan_alarm, NULL);
91 static int fan_alarm_init(struct gpio_fan_data *fan_data,
92 struct gpio_fan_alarm *alarm)
96 struct platform_device *pdev = fan_data->pdev;
98 fan_data->alarm = alarm;
100 err = devm_gpio_request(&pdev->dev, alarm->gpio, "GPIO fan alarm");
104 err = gpio_direction_input(alarm->gpio);
108 err = device_create_file(&pdev->dev, &dev_attr_fan1_alarm);
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);
130 device_remove_file(&pdev->dev, &dev_attr_fan1_alarm);
134 static void fan_alarm_free(struct gpio_fan_data *fan_data)
136 struct platform_device *pdev = fan_data->pdev;
138 device_remove_file(&pdev->dev, &dev_attr_fan1_alarm);
145 /* Must be called with fan_data->lock held, except during initialization. */
146 static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val)
150 for (i = 0; i < fan_data->num_ctrl; i++)
151 gpio_set_value(fan_data->ctrl[i], (ctrl_val >> i) & 1);
154 static int __get_fan_ctrl(struct gpio_fan_data *fan_data)
159 for (i = 0; i < fan_data->num_ctrl; i++) {
162 value = gpio_get_value(fan_data->ctrl[i]);
163 ctrl_val |= (value << i);
168 /* Must be called with fan_data->lock held, except during initialization. */
169 static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index)
171 if (fan_data->speed_index == speed_index)
174 __set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val);
175 fan_data->speed_index = speed_index;
178 static int get_fan_speed_index(struct gpio_fan_data *fan_data)
180 int ctrl_val = __get_fan_ctrl(fan_data);
183 for (i = 0; i < fan_data->num_speed; i++)
184 if (fan_data->speed[i].ctrl_val == ctrl_val)
187 dev_warn(&fan_data->pdev->dev,
188 "missing speed array entry for GPIO value 0x%x\n", ctrl_val);
193 static int rpm_to_speed_index(struct gpio_fan_data *fan_data, int rpm)
195 struct gpio_fan_speed *speed = fan_data->speed;
198 for (i = 0; i < fan_data->num_speed; i++)
199 if (speed[i].rpm >= rpm)
202 return fan_data->num_speed - 1;
205 static ssize_t show_pwm(struct device *dev,
206 struct device_attribute *attr, char *buf)
208 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
209 u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1);
211 return sprintf(buf, "%d\n", pwm);
214 static ssize_t set_pwm(struct device *dev, struct device_attribute *attr,
215 const char *buf, size_t count)
217 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
222 if (kstrtoul(buf, 10, &pwm) || pwm > 255)
225 mutex_lock(&fan_data->lock);
227 if (!fan_data->pwm_enable) {
232 speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255);
233 set_fan_speed(fan_data, speed_index);
236 mutex_unlock(&fan_data->lock);
241 static ssize_t show_pwm_enable(struct device *dev,
242 struct device_attribute *attr, char *buf)
244 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
246 return sprintf(buf, "%d\n", fan_data->pwm_enable);
249 static ssize_t set_pwm_enable(struct device *dev, struct device_attribute *attr,
250 const char *buf, size_t count)
252 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
255 if (kstrtoul(buf, 10, &val) || val > 1)
258 if (fan_data->pwm_enable == val)
261 mutex_lock(&fan_data->lock);
263 fan_data->pwm_enable = val;
265 /* Disable manual control mode: set fan at full speed. */
267 set_fan_speed(fan_data, fan_data->num_speed - 1);
269 mutex_unlock(&fan_data->lock);
274 static ssize_t show_pwm_mode(struct device *dev,
275 struct device_attribute *attr, char *buf)
277 return sprintf(buf, "0\n");
280 static ssize_t show_rpm_min(struct device *dev,
281 struct device_attribute *attr, char *buf)
283 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
285 return sprintf(buf, "%d\n", fan_data->speed[0].rpm);
288 static ssize_t show_rpm_max(struct device *dev,
289 struct device_attribute *attr, char *buf)
291 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
293 return sprintf(buf, "%d\n",
294 fan_data->speed[fan_data->num_speed - 1].rpm);
297 static ssize_t show_rpm(struct device *dev,
298 struct device_attribute *attr, char *buf)
300 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
302 return sprintf(buf, "%d\n", fan_data->speed[fan_data->speed_index].rpm);
305 static ssize_t set_rpm(struct device *dev, struct device_attribute *attr,
306 const char *buf, size_t count)
308 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
312 if (kstrtoul(buf, 10, &rpm))
315 mutex_lock(&fan_data->lock);
317 if (!fan_data->pwm_enable) {
322 set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm));
325 mutex_unlock(&fan_data->lock);
330 static DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm, set_pwm);
331 static DEVICE_ATTR(pwm1_enable, S_IRUGO | S_IWUSR,
332 show_pwm_enable, set_pwm_enable);
333 static DEVICE_ATTR(pwm1_mode, S_IRUGO, show_pwm_mode, NULL);
334 static DEVICE_ATTR(fan1_min, S_IRUGO, show_rpm_min, NULL);
335 static DEVICE_ATTR(fan1_max, S_IRUGO, show_rpm_max, NULL);
336 static DEVICE_ATTR(fan1_input, S_IRUGO, show_rpm, NULL);
337 static DEVICE_ATTR(fan1_target, S_IRUGO | S_IWUSR, show_rpm, set_rpm);
339 static struct attribute *gpio_fan_ctrl_attributes[] = {
341 &dev_attr_pwm1_enable.attr,
342 &dev_attr_pwm1_mode.attr,
343 &dev_attr_fan1_input.attr,
344 &dev_attr_fan1_target.attr,
345 &dev_attr_fan1_min.attr,
346 &dev_attr_fan1_max.attr,
350 static const struct attribute_group gpio_fan_ctrl_group = {
351 .attrs = gpio_fan_ctrl_attributes,
354 static int fan_ctrl_init(struct gpio_fan_data *fan_data,
355 struct gpio_fan_platform_data *pdata)
357 struct platform_device *pdev = fan_data->pdev;
358 int num_ctrl = pdata->num_ctrl;
359 unsigned *ctrl = pdata->ctrl;
362 for (i = 0; i < num_ctrl; i++) {
363 err = devm_gpio_request(&pdev->dev, ctrl[i],
368 err = gpio_direction_output(ctrl[i], gpio_get_value(ctrl[i]));
373 fan_data->num_ctrl = num_ctrl;
374 fan_data->ctrl = ctrl;
375 fan_data->num_speed = pdata->num_speed;
376 fan_data->speed = pdata->speed;
377 fan_data->pwm_enable = true; /* Enable manual fan speed control. */
378 fan_data->speed_index = get_fan_speed_index(fan_data);
379 if (fan_data->speed_index < 0)
382 err = sysfs_create_group(&pdev->dev.kobj, &gpio_fan_ctrl_group);
386 static void fan_ctrl_free(struct gpio_fan_data *fan_data)
388 struct platform_device *pdev = fan_data->pdev;
390 sysfs_remove_group(&pdev->dev.kobj, &gpio_fan_ctrl_group);
397 static ssize_t show_name(struct device *dev,
398 struct device_attribute *attr, char *buf)
400 return sprintf(buf, "gpio-fan\n");
403 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
406 #ifdef CONFIG_OF_GPIO
408 * Translate OpenFirmware node properties into platform_data
410 static int gpio_fan_get_of_pdata(struct device *dev,
411 struct gpio_fan_platform_data *pdata)
413 struct device_node *node;
414 struct gpio_fan_speed *speed;
418 struct property *prop;
423 /* Fill GPIO pin array */
424 pdata->num_ctrl = of_gpio_count(node);
425 if (!pdata->num_ctrl) {
426 dev_err(dev, "gpios DT property empty / missing");
429 ctrl = devm_kzalloc(dev, pdata->num_ctrl * sizeof(unsigned),
433 for (i = 0; i < pdata->num_ctrl; i++) {
436 val = of_get_gpio(node, i);
443 /* Get number of RPM/ctrl_val pairs in speed map */
444 prop = of_find_property(node, "gpio-fan,speed-map", &i);
446 dev_err(dev, "gpio-fan,speed-map DT property missing");
450 if (i == 0 || i & 1) {
451 dev_err(dev, "gpio-fan,speed-map contains zero/odd number of entries");
454 pdata->num_speed = i / 2;
458 * Speed map is in the form <RPM ctrl_val RPM ctrl_val ...>
459 * this needs splitting into pairs to create gpio_fan_speed structs
461 speed = devm_kzalloc(dev,
462 pdata->num_speed * sizeof(struct gpio_fan_speed),
467 for (i = 0; i < pdata->num_speed; i++) {
468 p = of_prop_next_u32(prop, p, &u);
472 p = of_prop_next_u32(prop, p, &u);
475 speed[i].ctrl_val = u;
477 pdata->speed = speed;
479 /* Alarm GPIO if one exists */
480 if (of_gpio_named_count(node, "alarm-gpios")) {
481 struct gpio_fan_alarm *alarm;
483 enum of_gpio_flags flags;
485 alarm = devm_kzalloc(dev, sizeof(struct gpio_fan_alarm),
490 val = of_get_named_gpio_flags(node, "alarm-gpios", 0, &flags);
494 alarm->active_low = flags & OF_GPIO_ACTIVE_LOW;
496 pdata->alarm = alarm;
502 static struct of_device_id of_gpio_fan_match[] __devinitdata = {
503 { .compatible = "gpio-fan", },
506 #endif /* CONFIG_OF_GPIO */
508 static int __devinit gpio_fan_probe(struct platform_device *pdev)
511 struct gpio_fan_data *fan_data;
512 struct gpio_fan_platform_data *pdata = pdev->dev.platform_data;
514 #ifdef CONFIG_OF_GPIO
516 pdata = devm_kzalloc(&pdev->dev,
517 sizeof(struct gpio_fan_platform_data),
522 err = gpio_fan_get_of_pdata(&pdev->dev, pdata);
526 #else /* CONFIG_OF_GPIO */
529 #endif /* CONFIG_OF_GPIO */
531 fan_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_fan_data),
536 fan_data->pdev = pdev;
537 platform_set_drvdata(pdev, fan_data);
538 mutex_init(&fan_data->lock);
540 /* Configure alarm GPIO if available. */
542 err = fan_alarm_init(fan_data, pdata->alarm);
547 /* Configure control GPIOs if available. */
548 if (pdata->ctrl && pdata->num_ctrl > 0) {
549 if (!pdata->speed || pdata->num_speed <= 1) {
553 err = fan_ctrl_init(fan_data, pdata);
558 err = device_create_file(&pdev->dev, &dev_attr_name);
562 /* Make this driver part of hwmon class. */
563 fan_data->hwmon_dev = hwmon_device_register(&pdev->dev);
564 if (IS_ERR(fan_data->hwmon_dev)) {
565 err = PTR_ERR(fan_data->hwmon_dev);
566 goto err_remove_name;
569 dev_info(&pdev->dev, "GPIO fan initialized\n");
574 device_remove_file(&pdev->dev, &dev_attr_name);
577 fan_ctrl_free(fan_data);
580 fan_alarm_free(fan_data);
584 static int __devexit gpio_fan_remove(struct platform_device *pdev)
586 struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);
588 hwmon_device_unregister(fan_data->hwmon_dev);
589 device_remove_file(&pdev->dev, &dev_attr_name);
591 fan_alarm_free(fan_data);
593 fan_ctrl_free(fan_data);
598 #ifdef CONFIG_PM_SLEEP
599 static int gpio_fan_suspend(struct device *dev)
601 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
603 if (fan_data->ctrl) {
604 fan_data->resume_speed = fan_data->speed_index;
605 set_fan_speed(fan_data, 0);
611 static int gpio_fan_resume(struct device *dev)
613 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
616 set_fan_speed(fan_data, fan_data->resume_speed);
621 static SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume);
622 #define GPIO_FAN_PM &gpio_fan_pm
624 #define GPIO_FAN_PM NULL
627 static struct platform_driver gpio_fan_driver = {
628 .probe = gpio_fan_probe,
629 .remove = __devexit_p(gpio_fan_remove),
633 .of_match_table = of_match_ptr(of_gpio_fan_match),
637 module_platform_driver(gpio_fan_driver);
639 MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
640 MODULE_DESCRIPTION("GPIO FAN driver");
641 MODULE_LICENSE("GPL");
642 MODULE_ALIAS("platform:gpio-fan");