linux/drivers/hwmon/gpio-fan.c

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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>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/of_gpio.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;
/*
* 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);
return err;
}
/*
* 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 -ENODEV;
}
static int rpm_to_speed_index(struct gpio_fan_data *fan_data, unsigned long 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 umode_t gpio_fan_is_visible(struct kobject *kobj,
struct attribute *attr, int index)
{
struct device *dev = container_of(kobj, struct device, kobj);
struct gpio_fan_data *data = dev_get_drvdata(dev);
if (index == 0 && !data->alarm)
return 0;
if (index > 0 && !data->ctrl)
return 0;
return attr->mode;
}
static struct attribute *gpio_fan_attributes[] = {
&dev_attr_fan1_alarm.attr, /* 0 */
&dev_attr_pwm1.attr, /* 1 */
&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_group = {
.attrs = gpio_fan_attributes,
.is_visible = gpio_fan_is_visible,
};
static const struct attribute_group *gpio_fan_groups[] = {
&gpio_fan_group,
NULL
};
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 fan_data->speed_index;
return 0;
}
#ifdef CONFIG_OF_GPIO
/*
* Translate OpenFirmware node properties into platform_data
*/
static int gpio_fan_get_of_pdata(struct device *dev,
struct gpio_fan_platform_data *pdata)
{
struct device_node *node;
struct gpio_fan_speed *speed;
unsigned *ctrl;
unsigned i;
u32 u;
struct property *prop;
const __be32 *p;
node = dev->of_node;
/* Fill GPIO pin array */
pdata->num_ctrl = of_gpio_count(node);
if (pdata->num_ctrl <= 0) {
dev_err(dev, "gpios DT property empty / missing");
return -ENODEV;
}
ctrl = devm_kzalloc(dev, pdata->num_ctrl * sizeof(unsigned),
GFP_KERNEL);
if (!ctrl)
return -ENOMEM;
for (i = 0; i < pdata->num_ctrl; i++) {
int val;
val = of_get_gpio(node, i);
if (val < 0)
return val;
ctrl[i] = val;
}
pdata->ctrl = ctrl;
/* Get number of RPM/ctrl_val pairs in speed map */
prop = of_find_property(node, "gpio-fan,speed-map", &i);
if (!prop) {
dev_err(dev, "gpio-fan,speed-map DT property missing");
return -ENODEV;
}
i = i / sizeof(u32);
if (i == 0 || i & 1) {
dev_err(dev, "gpio-fan,speed-map contains zero/odd number of entries");
return -ENODEV;
}
pdata->num_speed = i / 2;
/*
* Populate speed map
* Speed map is in the form <RPM ctrl_val RPM ctrl_val ...>
* this needs splitting into pairs to create gpio_fan_speed structs
*/
speed = devm_kzalloc(dev,
pdata->num_speed * sizeof(struct gpio_fan_speed),
GFP_KERNEL);
if (!speed)
return -ENOMEM;
p = NULL;
for (i = 0; i < pdata->num_speed; i++) {
p = of_prop_next_u32(prop, p, &u);
if (!p)
return -ENODEV;
speed[i].rpm = u;
p = of_prop_next_u32(prop, p, &u);
if (!p)
return -ENODEV;
speed[i].ctrl_val = u;
}
pdata->speed = speed;
/* Alarm GPIO if one exists */
if (of_gpio_named_count(node, "alarm-gpios") > 0) {
struct gpio_fan_alarm *alarm;
int val;
enum of_gpio_flags flags;
alarm = devm_kzalloc(dev, sizeof(struct gpio_fan_alarm),
GFP_KERNEL);
if (!alarm)
return -ENOMEM;
val = of_get_named_gpio_flags(node, "alarm-gpios", 0, &flags);
if (val < 0)
return val;
alarm->gpio = val;
alarm->active_low = flags & OF_GPIO_ACTIVE_LOW;
pdata->alarm = alarm;
}
return 0;
}
static const struct of_device_id of_gpio_fan_match[] = {
{ .compatible = "gpio-fan", },
{},
};
#endif /* CONFIG_OF_GPIO */
static int gpio_fan_probe(struct platform_device *pdev)
{
int err;
struct gpio_fan_data *fan_data;
struct gpio_fan_platform_data *pdata = dev_get_platdata(&pdev->dev);
#ifdef CONFIG_OF_GPIO
if (!pdata) {
pdata = devm_kzalloc(&pdev->dev,
sizeof(struct gpio_fan_platform_data),
GFP_KERNEL);
if (!pdata)
return -ENOMEM;
err = gpio_fan_get_of_pdata(&pdev->dev, pdata);
if (err)
return err;
}
#else /* CONFIG_OF_GPIO */
if (!pdata)
return -EINVAL;
#endif /* CONFIG_OF_GPIO */
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)
return -EINVAL;
err = fan_ctrl_init(fan_data, pdata);
if (err)
return err;
}
/* Make this driver part of hwmon class. */
fan_data->hwmon_dev =
devm_hwmon_device_register_with_groups(&pdev->dev,
"gpio_fan", fan_data,
gpio_fan_groups);
if (IS_ERR(fan_data->hwmon_dev))
return PTR_ERR(fan_data->hwmon_dev);
dev_info(&pdev->dev, "GPIO fan initialized\n");
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,
.driver = {
.name = "gpio-fan",
.pm = GPIO_FAN_PM,
#ifdef CONFIG_OF_GPIO
.of_match_table = of_match_ptr(of_gpio_fan_match),
#endif
},
};
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");