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Commit d6fe1360 authored by Simon Guinot's avatar Simon Guinot Committed by Guenter Roeck
Browse files

hwmon: add generic GPIO fan driver 



This patch adds hwmon support for fans connected to GPIO lines.

Platform specific information such as GPIO pinout and speed conversion array
(rpm from/to GPIO value) are passed to the driver via platform_data.

Signed-off-by: default avatarSimon Guinot <sguinot@lacie.com>
Signed-off-by: default avatarGuenter Roeck <guenter.roeck@ericsson.com>
parent 32478006

drivers/hwmon/Kconfig

+9 −0
Original line number Original line Diff line number Diff line
@@ -399,6 +399,15 @@ config SENSORS_GL520SM 
	  This driver can also be built as a module.  If so, the module

	  This driver can also be built as a module.  If so, the module

	  will be called gl520sm.

	  will be called gl520sm.





config SENSORS_GPIO_FAN

	tristate "GPIO fan"

	depends on GENERIC_GPIO

	help

	  If you say yes here you get support for fans connected to GPIO lines.



	  This driver can also be built as a module.  If so, the module

	  will be called gpio-fan.



config SENSORS_CORETEMP

config SENSORS_CORETEMP

	tristate "Intel Core/Core2/Atom temperature sensor"

	tristate "Intel Core/Core2/Atom temperature sensor"

	depends on X86 && PCI && EXPERIMENTAL

	depends on X86 && PCI && EXPERIMENTAL

drivers/hwmon/Makefile

+1 −0
Original line number Original line Diff line number Diff line
@@ -51,6 +51,7 @@ obj-$(CONFIG_SENSORS_FSCHMD) += fschmd.o 
obj-$(CONFIG_SENSORS_G760A)	+= g760a.o

obj-$(CONFIG_SENSORS_G760A)	+= g760a.o

obj-$(CONFIG_SENSORS_GL518SM)	+= gl518sm.o

obj-$(CONFIG_SENSORS_GL518SM)	+= gl518sm.o

obj-$(CONFIG_SENSORS_GL520SM)	+= gl520sm.o

obj-$(CONFIG_SENSORS_GL520SM)	+= gl520sm.o

obj-$(CONFIG_SENSORS_GPIO_FAN)	+= gpio-fan.o

obj-$(CONFIG_SENSORS_ULTRA45)	+= ultra45_env.o

obj-$(CONFIG_SENSORS_ULTRA45)	+= ultra45_env.o

obj-$(CONFIG_SENSORS_I5K_AMB)	+= i5k_amb.o

obj-$(CONFIG_SENSORS_I5K_AMB)	+= i5k_amb.o

obj-$(CONFIG_SENSORS_IBMAEM)	+= ibmaem.o

obj-$(CONFIG_SENSORS_IBMAEM)	+= ibmaem.o

drivers/hwmon/gpio-fan.c

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Original line number Original line Diff line number Diff line 
/*

 * 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

	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 = gpio_request(alarm->gpio, "GPIO fan alarm");

	if (err)

		return err;



	err = gpio_direction_input(alarm->gpio);

	if (err)

		goto err_free_gpio;



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

	if (err)

		goto err_free_gpio;



	/*

	 * 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);

	set_irq_type(alarm_irq, IRQ_TYPE_EDGE_BOTH);

	err = request_irq(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);

err_free_gpio:

	gpio_free(alarm->gpio);



	return err;

}



static void fan_alarm_free(struct gpio_fan_data *fan_data)

{

	struct platform_device *pdev = fan_data->pdev;

	int alarm_irq = gpio_to_irq(fan_data->alarm->gpio);



	if (alarm_irq >= 0)

		free_irq(alarm_irq, fan_data);

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

	gpio_free(fan_data->alarm->gpio);

}



/*

 * 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 (strict_strtoul(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 (strict_strtoul(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 (strict_strtoul(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 = gpio_request(ctrl[i], "GPIO fan control");

		if (err)

			goto err_free_gpio;



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

		if (err) {

			gpio_free(ctrl[i]);

			goto err_free_gpio;

		}

	}



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

	if (err)

		goto err_free_gpio;



	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) {

		err = -ENODEV;

		goto err_free_gpio;

	}



	return 0;



err_free_gpio:

	for (i = i - 1; i >= 0; i--)

		gpio_free(ctrl[i]);



	return err;

}



static void fan_ctrl_free(struct gpio_fan_data *fan_data)

{

	struct platform_device *pdev = fan_data->pdev;

	int i;



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

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

		gpio_free(fan_data->ctrl[i]);

}



/*

 * 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 = kzalloc(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)

			goto err_free_data;

	}



	/* 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);

err_free_data:

	platform_set_drvdata(pdev, NULL);

	kfree(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);

	kfree(fan_data);



	return 0;

}



#ifdef CONFIG_PM

static int gpio_fan_suspend(struct platform_device *pdev, pm_message_t state)

{

	struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);



	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 platform_device *pdev)

{

	struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);



	if (fan_data->ctrl)

		set_fan_speed(fan_data, fan_data->resume_speed);



	return 0;

}

#else

#define gpio_fan_suspend NULL

#define gpio_fan_resume NULL

#endif



static struct platform_driver gpio_fan_driver = {

	.probe		= gpio_fan_probe,

	.remove		= __devexit_p(gpio_fan_remove),

	.suspend	= gpio_fan_suspend,

	.resume		= gpio_fan_resume,

	.driver	= {

		.name	= "gpio-fan",

	},

};



static int __init gpio_fan_init(void)

{

	return platform_driver_register(&gpio_fan_driver);

}



static void __exit gpio_fan_exit(void)

{

	platform_driver_unregister(&gpio_fan_driver);

}



module_init(gpio_fan_init);

module_exit(gpio_fan_exit);



MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");

MODULE_DESCRIPTION("GPIO FAN driver");

MODULE_LICENSE("GPL");

MODULE_ALIAS("platform:gpio-fan");

include/linux/gpio-fan.h

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Original line number Original line Diff line number Diff line 
/*

 * include/linux/gpio-fan.h

 *

 * Platform data structure for GPIO fan driver

 *

 * This file is licensed under the terms of the GNU General Public

 * License version 2.  This program is licensed "as is" without any

 * warranty of any kind, whether express or implied.

 */



#ifndef __LINUX_GPIO_FAN_H

#define __LINUX_GPIO_FAN_H



struct gpio_fan_alarm {

	unsigned	gpio;

	unsigned	active_low;

};



struct gpio_fan_speed {

	int rpm;

	int ctrl_val;

};



struct gpio_fan_platform_data {

	int			num_ctrl;

	unsigned		*ctrl;	/* fan control GPIOs. */

	struct gpio_fan_alarm	*alarm;	/* fan alarm GPIO. */

	/*

	 * Speed conversion array: rpm from/to GPIO bit field.

	 * This array _must_ be sorted in ascending rpm order.

	 */

	int			num_speed;

	struct gpio_fan_speed	*speed;

};



#endif /* __LINUX_GPIO_FAN_H */