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linux/drivers/hwmon/gpio-fan.c
Axel Lin 4f5b7994f0 hwmon: (gpio-fan) Fix fan_ctrl_init error path 
In current implementation, the sysfs entries is not removed before return -ENODEV.

Creating the sysfs attribute should be the last thing done by the function,
after all the rest has been successful.
Otherwise there is a small window during which user-space can access the attribute
but the driver isn't ready to deal with the requests.

Fix it by moving sysfs_create_group to be the last thing done by the function.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Simon Guinot <sguinot@lacie.com>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
2010-11-11 09:43:51 -08:00

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/*
* 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;
}
}
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;
}
err = sysfs_create_group(&pdev->dev.kobj, &gpio_fan_ctrl_group);
if (err)
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");
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