drivers/hwmon/gpio-fan.c - kernel/msm-4.9 - Gitiles

 /*
  * gpio-fan.c - Hwmon driver for fans connected to GPIO lines.
  *
  * Copyright (C) 2010 LaCie
  *
  * Author: Simon Guinot <sguinot@lacie.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */

 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/platform_device.h>
 #include <linux/err.h>
 #include <linux/mutex.h>
 #include <linux/hwmon.h>
 #include <linux/gpio.h>
 #include <linux/gpio-fan.h>

 struct gpio_fan_data {
 	struct platform_device	*pdev;
 	struct device		*hwmon_dev;
 	struct mutex		lock; /* lock GPIOs operations. */
 	int			num_ctrl;
 	unsigned		*ctrl;
 	int			num_speed;
 	struct gpio_fan_speed	*speed;
 	int			speed_index;
 #ifdef CONFIG_PM_SLEEP
 	int			resume_speed;
 #endif
 	bool			pwm_enable;
 	struct gpio_fan_alarm	*alarm;
 	struct work_struct	alarm_work;
 };

 /*
  * Alarm GPIO.
  */

 static void fan_alarm_notify(struct work_struct *ws)
 {
 	struct gpio_fan_data *fan_data =
 		container_of(ws, struct gpio_fan_data, alarm_work);

 	sysfs_notify(&fan_data->pdev->dev.kobj, NULL, "fan1_alarm");
 	kobject_uevent(&fan_data->pdev->dev.kobj, KOBJ_CHANGE);
 }

 static irqreturn_t fan_alarm_irq_handler(int irq, void *dev_id)
 {
 	struct gpio_fan_data *fan_data = dev_id;

 	schedule_work(&fan_data->alarm_work);

 	return IRQ_NONE;
 }

 static ssize_t show_fan_alarm(struct device *dev,
 			      struct device_attribute *attr, char *buf)
 {
 	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 	struct gpio_fan_alarm *alarm = fan_data->alarm;
 	int value = gpio_get_value(alarm->gpio);

 	if (alarm->active_low)
 		value = !value;

 	return sprintf(buf, "%d\n", value);
 }

 static DEVICE_ATTR(fan1_alarm, S_IRUGO, show_fan_alarm, NULL);

 static int fan_alarm_init(struct gpio_fan_data *fan_data,
 			  struct gpio_fan_alarm *alarm)
 {
 	int err;
 	int alarm_irq;
 	struct platform_device *pdev = fan_data->pdev;

 	fan_data->alarm = alarm;

 	err = devm_gpio_request(&pdev->dev, alarm->gpio, "GPIO fan alarm");
 	if (err)
 		return err;

 	err = gpio_direction_input(alarm->gpio);
 	if (err)
 		return err;

 	err = device_create_file(&pdev->dev, &dev_attr_fan1_alarm);
 	if (err)
 		return err;

 	/*
 	 * If the alarm GPIO don't support interrupts, just leave
 	 * without initializing the fail notification support.
 	 */
 	alarm_irq = gpio_to_irq(alarm->gpio);
 	if (alarm_irq < 0)
 		return 0;

 	INIT_WORK(&fan_data->alarm_work, fan_alarm_notify);
 	irq_set_irq_type(alarm_irq, IRQ_TYPE_EDGE_BOTH);
 	err = devm_request_irq(&pdev->dev, alarm_irq, fan_alarm_irq_handler,
 			       IRQF_SHARED, "GPIO fan alarm", fan_data);
 	if (err)
 		goto err_free_sysfs;

 	return 0;

 err_free_sysfs:
 	device_remove_file(&pdev->dev, &dev_attr_fan1_alarm);
 	return err;
 }

 static void fan_alarm_free(struct gpio_fan_data *fan_data)
 {
 	struct platform_device *pdev = fan_data->pdev;

 	device_remove_file(&pdev->dev, &dev_attr_fan1_alarm);
 }

 /*
  * Control GPIOs.
  */

 /* Must be called with fan_data->lock held, except during initialization. */
 static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val)
 {
 	int i;

 	for (i = 0; i < fan_data->num_ctrl; i++)
 		gpio_set_value(fan_data->ctrl[i], (ctrl_val >> i) & 1);
 }

 static int __get_fan_ctrl(struct gpio_fan_data *fan_data)
 {
 	int i;
 	int ctrl_val = 0;

 	for (i = 0; i < fan_data->num_ctrl; i++) {
 		int value;

 		value = gpio_get_value(fan_data->ctrl[i]);
 		ctrl_val |= (value << i);
 	}
 	return ctrl_val;
 }

 /* Must be called with fan_data->lock held, except during initialization. */
 static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index)
 {
 	if (fan_data->speed_index == speed_index)
 		return;

 	__set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val);
 	fan_data->speed_index = speed_index;
 }

 static int get_fan_speed_index(struct gpio_fan_data *fan_data)
 {
 	int ctrl_val = __get_fan_ctrl(fan_data);
 	int i;

 	for (i = 0; i < fan_data->num_speed; i++)
 		if (fan_data->speed[i].ctrl_val == ctrl_val)
 			return i;

 	dev_warn(&fan_data->pdev->dev,
 		 "missing speed array entry for GPIO value 0x%x\n", ctrl_val);

 	return -EINVAL;
 }

 static int rpm_to_speed_index(struct gpio_fan_data *fan_data, int rpm)
 {
 	struct gpio_fan_speed *speed = fan_data->speed;
 	int i;

 	for (i = 0; i < fan_data->num_speed; i++)
 		if (speed[i].rpm >= rpm)
 			return i;

 	return fan_data->num_speed - 1;
 }

 static ssize_t show_pwm(struct device *dev,
 			struct device_attribute *attr, char *buf)
 {
 	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 	u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1);

 	return sprintf(buf, "%d\n", pwm);
 }

 static ssize_t set_pwm(struct device *dev, struct device_attribute *attr,
 		       const char *buf, size_t count)
 {
 	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 	unsigned long pwm;
 	int speed_index;
 	int ret = count;

 	if (kstrtoul(buf, 10, &pwm) || pwm > 255)
 		return -EINVAL;

 	mutex_lock(&fan_data->lock);

 	if (!fan_data->pwm_enable) {
 		ret = -EPERM;
 		goto exit_unlock;
 	}

 	speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255);
 	set_fan_speed(fan_data, speed_index);

 exit_unlock:
 	mutex_unlock(&fan_data->lock);

 	return ret;
 }

 static ssize_t show_pwm_enable(struct device *dev,
 			       struct device_attribute *attr, char *buf)
 {
 	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);

 	return sprintf(buf, "%d\n", fan_data->pwm_enable);
 }

 static ssize_t set_pwm_enable(struct device *dev, struct device_attribute *attr,
 			      const char *buf, size_t count)
 {
 	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 	unsigned long val;

 	if (kstrtoul(buf, 10, &val) || val > 1)
 		return -EINVAL;

 	if (fan_data->pwm_enable == val)
 		return count;

 	mutex_lock(&fan_data->lock);

 	fan_data->pwm_enable = val;

 	/* Disable manual control mode: set fan at full speed. */
 	if (val == 0)
 		set_fan_speed(fan_data, fan_data->num_speed - 1);

 	mutex_unlock(&fan_data->lock);

 	return count;
 }

 static ssize_t show_pwm_mode(struct device *dev,
 			     struct device_attribute *attr, char *buf)
 {
 	return sprintf(buf, "0\n");
 }

 static ssize_t show_rpm_min(struct device *dev,
 			    struct device_attribute *attr, char *buf)
 {
 	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);

 	return sprintf(buf, "%d\n", fan_data->speed[0].rpm);
 }

 static ssize_t show_rpm_max(struct device *dev,
 			    struct device_attribute *attr, char *buf)
 {
 	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);

 	return sprintf(buf, "%d\n",
 		       fan_data->speed[fan_data->num_speed - 1].rpm);
 }

 static ssize_t show_rpm(struct device *dev,
 			struct device_attribute *attr, char *buf)
 {
 	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);

 	return sprintf(buf, "%d\n", fan_data->speed[fan_data->speed_index].rpm);
 }

 static ssize_t set_rpm(struct device *dev, struct device_attribute *attr,
 		       const char *buf, size_t count)
 {
 	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 	unsigned long rpm;
 	int ret = count;

 	if (kstrtoul(buf, 10, &rpm))
 		return -EINVAL;

 	mutex_lock(&fan_data->lock);

 	if (!fan_data->pwm_enable) {
 		ret = -EPERM;
 		goto exit_unlock;
 	}

 	set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm));

 exit_unlock:
 	mutex_unlock(&fan_data->lock);

 	return ret;
 }

 static DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm, set_pwm);
 static DEVICE_ATTR(pwm1_enable, S_IRUGO | S_IWUSR,
 		   show_pwm_enable, set_pwm_enable);
 static DEVICE_ATTR(pwm1_mode, S_IRUGO, show_pwm_mode, NULL);
 static DEVICE_ATTR(fan1_min, S_IRUGO, show_rpm_min, NULL);
 static DEVICE_ATTR(fan1_max, S_IRUGO, show_rpm_max, NULL);
 static DEVICE_ATTR(fan1_input, S_IRUGO, show_rpm, NULL);
 static DEVICE_ATTR(fan1_target, S_IRUGO | S_IWUSR, show_rpm, set_rpm);

 static struct attribute *gpio_fan_ctrl_attributes[] = {
 	&dev_attr_pwm1.attr,
 	&dev_attr_pwm1_enable.attr,
 	&dev_attr_pwm1_mode.attr,
 	&dev_attr_fan1_input.attr,
 	&dev_attr_fan1_target.attr,
 	&dev_attr_fan1_min.attr,
 	&dev_attr_fan1_max.attr,
 	NULL
 };

 static const struct attribute_group gpio_fan_ctrl_group = {
 	.attrs = gpio_fan_ctrl_attributes,
 };

 static int fan_ctrl_init(struct gpio_fan_data *fan_data,
 			 struct gpio_fan_platform_data *pdata)
 {
 	struct platform_device *pdev = fan_data->pdev;
 	int num_ctrl = pdata->num_ctrl;
 	unsigned *ctrl = pdata->ctrl;
 	int i, err;

 	for (i = 0; i < num_ctrl; i++) {
 		err = devm_gpio_request(&pdev->dev, ctrl[i],
 					"GPIO fan control");
 		if (err)
 			return err;

 		err = gpio_direction_output(ctrl[i], gpio_get_value(ctrl[i]));
 		if (err)
 			return err;
 	}

 	fan_data->num_ctrl = num_ctrl;
 	fan_data->ctrl = ctrl;
 	fan_data->num_speed = pdata->num_speed;
 	fan_data->speed = pdata->speed;
 	fan_data->pwm_enable = true; /* Enable manual fan speed control. */
 	fan_data->speed_index = get_fan_speed_index(fan_data);
 	if (fan_data->speed_index < 0)
 		return -ENODEV;

 	err = sysfs_create_group(&pdev->dev.kobj, &gpio_fan_ctrl_group);
 	return err;
 }

 static void fan_ctrl_free(struct gpio_fan_data *fan_data)
 {
 	struct platform_device *pdev = fan_data->pdev;

 	sysfs_remove_group(&pdev->dev.kobj, &gpio_fan_ctrl_group);
 }

 /*
  * Platform driver.
  */

 static ssize_t show_name(struct device *dev,
 			 struct device_attribute *attr, char *buf)
 {
 	return sprintf(buf, "gpio-fan\n");
 }

 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);

 static int __devinit gpio_fan_probe(struct platform_device *pdev)
 {
 	int err;
 	struct gpio_fan_data *fan_data;
 	struct gpio_fan_platform_data *pdata = pdev->dev.platform_data;

 	if (!pdata)
 		return -EINVAL;

 	fan_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_fan_data),
 				GFP_KERNEL);
 	if (!fan_data)
 		return -ENOMEM;

 	fan_data->pdev = pdev;
 	platform_set_drvdata(pdev, fan_data);
 	mutex_init(&fan_data->lock);

 	/* Configure alarm GPIO if available. */
 	if (pdata->alarm) {
 		err = fan_alarm_init(fan_data, pdata->alarm);
 		if (err)
 			return err;
 	}

 	/* Configure control GPIOs if available. */
 	if (pdata->ctrl && pdata->num_ctrl > 0) {
 		if (!pdata->speed || pdata->num_speed <= 1) {
 			err = -EINVAL;
 			goto err_free_alarm;
 		}
 		err = fan_ctrl_init(fan_data, pdata);
 		if (err)
 			goto err_free_alarm;
 	}

 	err = device_create_file(&pdev->dev, &dev_attr_name);
 	if (err)
 		goto err_free_ctrl;

 	/* Make this driver part of hwmon class. */
 	fan_data->hwmon_dev = hwmon_device_register(&pdev->dev);
 	if (IS_ERR(fan_data->hwmon_dev)) {
 		err = PTR_ERR(fan_data->hwmon_dev);
 		goto err_remove_name;
 	}

 	dev_info(&pdev->dev, "GPIO fan initialized\n");

 	return 0;

 err_remove_name:
 	device_remove_file(&pdev->dev, &dev_attr_name);
 err_free_ctrl:
 	if (fan_data->ctrl)
 		fan_ctrl_free(fan_data);
 err_free_alarm:
 	if (fan_data->alarm)
 		fan_alarm_free(fan_data);
 	return err;
 }

 static int __devexit gpio_fan_remove(struct platform_device *pdev)
 {
 	struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);

 	hwmon_device_unregister(fan_data->hwmon_dev);
 	device_remove_file(&pdev->dev, &dev_attr_name);
 	if (fan_data->alarm)
 		fan_alarm_free(fan_data);
 	if (fan_data->ctrl)
 		fan_ctrl_free(fan_data);

 	return 0;
 }

 #ifdef CONFIG_PM_SLEEP
 static int gpio_fan_suspend(struct device *dev)
 {
 	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);

 	if (fan_data->ctrl) {
 		fan_data->resume_speed = fan_data->speed_index;
 		set_fan_speed(fan_data, 0);
 	}

 	return 0;
 }

 static int gpio_fan_resume(struct device *dev)
 {
 	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);

 	if (fan_data->ctrl)
 		set_fan_speed(fan_data, fan_data->resume_speed);

 	return 0;
 }

 static SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume);
 #define GPIO_FAN_PM	&gpio_fan_pm
 #else
 #define GPIO_FAN_PM	NULL
 #endif

 static struct platform_driver gpio_fan_driver = {
 	.probe		= gpio_fan_probe,
 	.remove		= __devexit_p(gpio_fan_remove),
 	.driver	= {
 		.name	= "gpio-fan",
 		.pm	= GPIO_FAN_PM,
 	},
 };

 module_platform_driver(gpio_fan_driver);

 MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
 MODULE_DESCRIPTION("GPIO FAN driver");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("platform:gpio-fan");
	/*
	* gpio-fan.c - Hwmon driver for fans connected to GPIO lines.
	*
	* Copyright (C) 2010 LaCie
	*
	* Author: Simon Guinot <sguinot@lacie.com>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*/

	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/slab.h>
	#include <linux/interrupt.h>
	#include <linux/irq.h>
	#include <linux/platform_device.h>
	#include <linux/err.h>
	#include <linux/mutex.h>
	#include <linux/hwmon.h>
	#include <linux/gpio.h>
	#include <linux/gpio-fan.h>

	struct gpio_fan_data {
	struct platform_device *pdev;
	struct device *hwmon_dev;
	struct mutex lock; /* lock GPIOs operations. */
	int num_ctrl;
	unsigned *ctrl;
	int num_speed;
	struct gpio_fan_speed *speed;
	int speed_index;
	#ifdef CONFIG_PM_SLEEP
	int resume_speed;
	#endif
	bool pwm_enable;
	struct gpio_fan_alarm *alarm;
	struct work_struct alarm_work;
	};

	/*
	* Alarm GPIO.
	*/

	static void fan_alarm_notify(struct work_struct *ws)
	{
	struct gpio_fan_data *fan_data =
	container_of(ws, struct gpio_fan_data, alarm_work);

	sysfs_notify(&fan_data->pdev->dev.kobj, NULL, "fan1_alarm");
	kobject_uevent(&fan_data->pdev->dev.kobj, KOBJ_CHANGE);
	}

	static irqreturn_t fan_alarm_irq_handler(int irq, void *dev_id)
	{
	struct gpio_fan_data *fan_data = dev_id;

	schedule_work(&fan_data->alarm_work);

	return IRQ_NONE;
	}

	static ssize_t show_fan_alarm(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
	struct gpio_fan_alarm *alarm = fan_data->alarm;
	int value = gpio_get_value(alarm->gpio);

	if (alarm->active_low)
	value = !value;

	return sprintf(buf, "%d\n", value);
	}

	static DEVICE_ATTR(fan1_alarm, S_IRUGO, show_fan_alarm, NULL);

	static int fan_alarm_init(struct gpio_fan_data *fan_data,
	struct gpio_fan_alarm *alarm)
	{
	int err;
	int alarm_irq;
	struct platform_device *pdev = fan_data->pdev;

	fan_data->alarm = alarm;

	err = devm_gpio_request(&pdev->dev, alarm->gpio, "GPIO fan alarm");
	if (err)
	return err;

	err = gpio_direction_input(alarm->gpio);
	if (err)
	return err;

	err = device_create_file(&pdev->dev, &dev_attr_fan1_alarm);
	if (err)
	return err;

	/*
	* If the alarm GPIO don't support interrupts, just leave
	* without initializing the fail notification support.
	*/
	alarm_irq = gpio_to_irq(alarm->gpio);
	if (alarm_irq < 0)
	return 0;

	INIT_WORK(&fan_data->alarm_work, fan_alarm_notify);
	irq_set_irq_type(alarm_irq, IRQ_TYPE_EDGE_BOTH);
	err = devm_request_irq(&pdev->dev, alarm_irq, fan_alarm_irq_handler,
	IRQF_SHARED, "GPIO fan alarm", fan_data);
	if (err)
	goto err_free_sysfs;

	return 0;

	err_free_sysfs:
	device_remove_file(&pdev->dev, &dev_attr_fan1_alarm);
	return err;
	}

	static void fan_alarm_free(struct gpio_fan_data *fan_data)
	{
	struct platform_device *pdev = fan_data->pdev;

	device_remove_file(&pdev->dev, &dev_attr_fan1_alarm);
	}

	/*
	* Control GPIOs.
	*/

	/* Must be called with fan_data->lock held, except during initialization. */
	static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val)
	{
	int i;

	for (i = 0; i < fan_data->num_ctrl; i++)
	gpio_set_value(fan_data->ctrl[i], (ctrl_val >> i) & 1);
	}

	static int __get_fan_ctrl(struct gpio_fan_data *fan_data)
	{
	int i;
	int ctrl_val = 0;

	for (i = 0; i < fan_data->num_ctrl; i++) {
	int value;

	value = gpio_get_value(fan_data->ctrl[i]);
	ctrl_val \|= (value << i);
	}
	return ctrl_val;
	}

	/* Must be called with fan_data->lock held, except during initialization. */
	static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index)
	{
	if (fan_data->speed_index == speed_index)
	return;

	__set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val);
	fan_data->speed_index = speed_index;
	}

	static int get_fan_speed_index(struct gpio_fan_data *fan_data)
	{
	int ctrl_val = __get_fan_ctrl(fan_data);
	int i;

	for (i = 0; i < fan_data->num_speed; i++)
	if (fan_data->speed[i].ctrl_val == ctrl_val)
	return i;

	dev_warn(&fan_data->pdev->dev,
	"missing speed array entry for GPIO value 0x%x\n", ctrl_val);

	return -EINVAL;
	}

	static int rpm_to_speed_index(struct gpio_fan_data *fan_data, int rpm)
	{
	struct gpio_fan_speed *speed = fan_data->speed;
	int i;

	for (i = 0; i < fan_data->num_speed; i++)
	if (speed[i].rpm >= rpm)
	return i;

	return fan_data->num_speed - 1;
	}

	static ssize_t show_pwm(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
	u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1);

	return sprintf(buf, "%d\n", pwm);
	}

	static ssize_t set_pwm(struct device dev, struct device_attribute attr,
	const char *buf, size_t count)
	{
	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
	unsigned long pwm;
	int speed_index;
	int ret = count;

	if (kstrtoul(buf, 10, &pwm) \|\| pwm > 255)
	return -EINVAL;

	mutex_lock(&fan_data->lock);

	if (!fan_data->pwm_enable) {
	ret = -EPERM;
	goto exit_unlock;
	}

	speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255);
	set_fan_speed(fan_data, speed_index);

	exit_unlock:
	mutex_unlock(&fan_data->lock);

	return ret;
	}

	static ssize_t show_pwm_enable(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);

	return sprintf(buf, "%d\n", fan_data->pwm_enable);
	}

	static ssize_t set_pwm_enable(struct device dev, struct device_attribute attr,
	const char *buf, size_t count)
	{
	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
	unsigned long val;

	if (kstrtoul(buf, 10, &val) \|\| val > 1)
	return -EINVAL;

	if (fan_data->pwm_enable == val)
	return count;

	mutex_lock(&fan_data->lock);

	fan_data->pwm_enable = val;

	/* Disable manual control mode: set fan at full speed. */
	if (val == 0)
	set_fan_speed(fan_data, fan_data->num_speed - 1);

	mutex_unlock(&fan_data->lock);

	return count;
	}

	static ssize_t show_pwm_mode(struct device *dev,
	struct device_attribute attr, char buf)
	{
	return sprintf(buf, "0\n");
	}

	static ssize_t show_rpm_min(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);

	return sprintf(buf, "%d\n", fan_data->speed[0].rpm);
	}

	static ssize_t show_rpm_max(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);

	return sprintf(buf, "%d\n",
	fan_data->speed[fan_data->num_speed - 1].rpm);
	}

	static ssize_t show_rpm(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);

	return sprintf(buf, "%d\n", fan_data->speed[fan_data->speed_index].rpm);
	}

	static ssize_t set_rpm(struct device dev, struct device_attribute attr,
	const char *buf, size_t count)
	{
	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
	unsigned long rpm;
	int ret = count;

	if (kstrtoul(buf, 10, &rpm))
	return -EINVAL;

	mutex_lock(&fan_data->lock);

	if (!fan_data->pwm_enable) {
	ret = -EPERM;
	goto exit_unlock;
	}

	set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm));

	exit_unlock:
	mutex_unlock(&fan_data->lock);

	return ret;
	}

	static DEVICE_ATTR(pwm1, S_IRUGO \| S_IWUSR, show_pwm, set_pwm);
	static DEVICE_ATTR(pwm1_enable, S_IRUGO \| S_IWUSR,
	show_pwm_enable, set_pwm_enable);
	static DEVICE_ATTR(pwm1_mode, S_IRUGO, show_pwm_mode, NULL);
	static DEVICE_ATTR(fan1_min, S_IRUGO, show_rpm_min, NULL);
	static DEVICE_ATTR(fan1_max, S_IRUGO, show_rpm_max, NULL);
	static DEVICE_ATTR(fan1_input, S_IRUGO, show_rpm, NULL);
	static DEVICE_ATTR(fan1_target, S_IRUGO \| S_IWUSR, show_rpm, set_rpm);

	static struct attribute *gpio_fan_ctrl_attributes[] = {
	&dev_attr_pwm1.attr,
	&dev_attr_pwm1_enable.attr,
	&dev_attr_pwm1_mode.attr,
	&dev_attr_fan1_input.attr,
	&dev_attr_fan1_target.attr,
	&dev_attr_fan1_min.attr,
	&dev_attr_fan1_max.attr,
	NULL
	};

	static const struct attribute_group gpio_fan_ctrl_group = {
	.attrs = gpio_fan_ctrl_attributes,
	};

	static int fan_ctrl_init(struct gpio_fan_data *fan_data,
	struct gpio_fan_platform_data *pdata)
	{
	struct platform_device *pdev = fan_data->pdev;
	int num_ctrl = pdata->num_ctrl;
	unsigned *ctrl = pdata->ctrl;
	int i, err;

	for (i = 0; i < num_ctrl; i++) {
	err = devm_gpio_request(&pdev->dev, ctrl[i],
	"GPIO fan control");
	if (err)
	return err;

	err = gpio_direction_output(ctrl[i], gpio_get_value(ctrl[i]));
	if (err)
	return err;
	}

	fan_data->num_ctrl = num_ctrl;
	fan_data->ctrl = ctrl;
	fan_data->num_speed = pdata->num_speed;
	fan_data->speed = pdata->speed;
	fan_data->pwm_enable = true; /* Enable manual fan speed control. */
	fan_data->speed_index = get_fan_speed_index(fan_data);
	if (fan_data->speed_index < 0)
	return -ENODEV;

	err = sysfs_create_group(&pdev->dev.kobj, &gpio_fan_ctrl_group);
	return err;
	}

	static void fan_ctrl_free(struct gpio_fan_data *fan_data)
	{
	struct platform_device *pdev = fan_data->pdev;

	sysfs_remove_group(&pdev->dev.kobj, &gpio_fan_ctrl_group);
	}

	/*
	* Platform driver.
	*/

	static ssize_t show_name(struct device *dev,
	struct device_attribute attr, char buf)
	{
	return sprintf(buf, "gpio-fan\n");
	}

	static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);

	static int __devinit gpio_fan_probe(struct platform_device *pdev)
	{
	int err;
	struct gpio_fan_data *fan_data;
	struct gpio_fan_platform_data *pdata = pdev->dev.platform_data;

	if (!pdata)
	return -EINVAL;

	fan_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_fan_data),
	GFP_KERNEL);
	if (!fan_data)
	return -ENOMEM;

	fan_data->pdev = pdev;
	platform_set_drvdata(pdev, fan_data);
	mutex_init(&fan_data->lock);

	/* Configure alarm GPIO if available. */
	if (pdata->alarm) {
	err = fan_alarm_init(fan_data, pdata->alarm);
	if (err)
	return err;
	}

	/* Configure control GPIOs if available. */
	if (pdata->ctrl && pdata->num_ctrl > 0) {
	if (!pdata->speed \|\| pdata->num_speed <= 1) {
	err = -EINVAL;
	goto err_free_alarm;
	}
	err = fan_ctrl_init(fan_data, pdata);
	if (err)
	goto err_free_alarm;
	}

	err = device_create_file(&pdev->dev, &dev_attr_name);
	if (err)
	goto err_free_ctrl;

	/* Make this driver part of hwmon class. */
	fan_data->hwmon_dev = hwmon_device_register(&pdev->dev);
	if (IS_ERR(fan_data->hwmon_dev)) {
	err = PTR_ERR(fan_data->hwmon_dev);
	goto err_remove_name;
	}

	dev_info(&pdev->dev, "GPIO fan initialized\n");

	return 0;

	err_remove_name:
	device_remove_file(&pdev->dev, &dev_attr_name);
	err_free_ctrl:
	if (fan_data->ctrl)
	fan_ctrl_free(fan_data);
	err_free_alarm:
	if (fan_data->alarm)
	fan_alarm_free(fan_data);
	return err;
	}

	static int __devexit gpio_fan_remove(struct platform_device *pdev)
	{
	struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);

	hwmon_device_unregister(fan_data->hwmon_dev);
	device_remove_file(&pdev->dev, &dev_attr_name);
	if (fan_data->alarm)
	fan_alarm_free(fan_data);
	if (fan_data->ctrl)
	fan_ctrl_free(fan_data);

	return 0;
	}

	#ifdef CONFIG_PM_SLEEP
	static int gpio_fan_suspend(struct device *dev)
	{
	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);

	if (fan_data->ctrl) {
	fan_data->resume_speed = fan_data->speed_index;
	set_fan_speed(fan_data, 0);
	}

	return 0;
	}

	static int gpio_fan_resume(struct device *dev)
	{
	struct gpio_fan_data *fan_data = dev_get_drvdata(dev);

	if (fan_data->ctrl)
	set_fan_speed(fan_data, fan_data->resume_speed);

	return 0;
	}

	static SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume);
	#define GPIO_FAN_PM &gpio_fan_pm
	#else
	#define GPIO_FAN_PM NULL
	#endif

	static struct platform_driver gpio_fan_driver = {
	.probe = gpio_fan_probe,
	.remove = __devexit_p(gpio_fan_remove),
	.driver = {
	.name = "gpio-fan",
	.pm = GPIO_FAN_PM,
	},
	};

	module_platform_driver(gpio_fan_driver);

	MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
	MODULE_DESCRIPTION("GPIO FAN driver");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS("platform:gpio-fan");