[PATCH 1/2] hwmon: add generic GPIO fan driver

Simon Guinot
2010-10-17T15:50:11Z

From: Simon Guinot <sguinot@lacie.com>

This patch adds hwmon support for the GPIO connected fan.

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

Signed-off-by: Simon Guinot <sguinot@lacie.com>
---
drivers/hwmon/Kconfig | 9 +
drivers/hwmon/Makefile | 1 +
drivers/hwmon/gpio-fan.c | 508 ++++++++++++++++++++++++++++++++++++++++++++++
include/linux/gpio-fan.h | 43 ++++
4 files changed, 561 insertions(+), 0 deletions(-)
create mode 100644 drivers/hwmon/gpio-fan.c
create mode 100644 include/linux/gpio-fan.h

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 4d4d09b..1dc57c1 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -399,6 +399,15 @@ config SENSORS_GL520SM
This driver can also be built as a module. If so, the module
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 the GPIO connected fan.
+
+ This driver can also be built as a module. If so, the module
+ will be called gpio-fan.
+
config SENSORS_CORETEMP
tristate "Intel Core/Core2/Atom temperature sensor"
depends on X86 && PCI && EXPERIMENTAL
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index e3c2484..a793e28 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -51,6 +51,7 @@ obj-$(CONFIG_SENSORS_FSCHMD) += fschmd.o
obj-$(CONFIG_SENSORS_G760A) += g760a.o
obj-$(CONFIG_SENSORS_GL518SM) += gl518sm.o
obj-$(CONFIG_SENSORS_GL520SM) += gl520sm.o
+obj-$(CONFIG_SENSORS_GPIO_FAN) += gpio-fan.o
obj-$(CONFIG_SENSORS_ULTRA45) += ultra45_env.o
obj-$(CONFIG_SENSORS_HDAPS) += hdaps.o
obj-$(CONFIG_SENSORS_I5K_AMB) += i5k_amb.o
diff --git a/drivers/hwmon/gpio-fan.c b/drivers/hwmon/gpio-fan.c
new file mode 100644
index 0000000..6cc8205
--- /dev/null
+++ b/drivers/hwmon/gpio-fan.c
@@ -0,0 +1,508 @@
+/*
+ * gpio-fan.c - Hwmon driver for GPIO connected fan.
+ *
+ * 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 ctrl_val;
+ int num_speed;
+ struct gpio_fan_speed *speed;
+ int pwm_enable;
+ struct gpio_fan_alarm *alarm;
+ struct work_struct alarm_work;
+ void (*platform_set_ctrl)(int num_ctrl, unsigned *ctrl, int ctrl_val);
+};
+
+/*
+ * 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_HANDLED;
+}
+
+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 __devinit
+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;
+
+ INIT_WORK(&fan_data->alarm_work, fan_alarm_notify);
+ alarm_irq = gpio_to_irq(alarm->gpio);
+ set_irq_type(alarm_irq, IRQ_TYPE_EDGE_BOTH);
+ err = request_irq(alarm_irq, fan_alarm_irq_handler, 0,
+ "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 __devexit fan_alarm_free(struct gpio_fan_data *fan_data)
+{
+ struct platform_device *pdev = fan_data->pdev;
+
+ free_irq(gpio_to_irq(fan_data->alarm->gpio), fan_data);
+ device_remove_file(&pdev->dev, &dev_attr_fan1_alarm);
+ gpio_free(fan_data->alarm->gpio);
+}
+
+/*
+ * Control GPIOs.
+ */
+
+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;
+}
+
+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++) {
+ int value = !!(ctrl_val & (1 << i));
+
+ gpio_set_value(fan_data->ctrl[i], value);
+ }
+}
+
+static void set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val)
+{
+ if (fan_data->platform_set_ctrl)
+ fan_data->platform_set_ctrl(fan_data->num_ctrl, fan_data->ctrl,
+ ctrl_val);
+ else
+ __set_fan_ctrl(fan_data, ctrl_val);
+
+ fan_data->ctrl_val = ctrl_val;
+}
+
+static int rpm_to_ctrl(struct gpio_fan_data *fan_data, int rpm)
+{
+ struct gpio_fan_speed *speed = fan_data->speed;
+ int num_speed = fan_data->num_speed;
+ int ctrl_val = speed[num_speed - 1].ctrl_val; /* Maximum speed */
+ int i;
+
+ for (i = 0; i < num_speed; i++) {
+ if (speed[i].rpm >= rpm) {
+ ctrl_val = speed[i].ctrl_val;
+ break;
+ }
+ }
+ return ctrl_val;
+}
+
+static int ctrl_to_rpm(struct gpio_fan_data *fan_data, int ctrl_val, int *rpm)
+{
+ struct gpio_fan_speed *speed = fan_data->speed;
+ int num_speed = fan_data->num_speed;
+ int i;
+
+ for (i = 0; i < num_speed; i++) {
+ if (speed[i].ctrl_val == ctrl_val) {
+ *rpm = speed[i].rpm;
+ return 0;
+ }
+ }
+ return -EINVAL;
+}
+
+static int pwm_to_rpm(struct gpio_fan_data *fan_data, u8 pwm)
+{
+ int rpm_min = fan_data->speed[0].rpm;
+ int rpm_max = fan_data->speed[fan_data->num_speed - 1].rpm;
+
+ return rpm_min + DIV_ROUND_UP((rpm_max - rpm_min), 255) * pwm;
+}
+
+static u8 rpm_to_pwm(struct gpio_fan_data *fan_data, int rpm)
+{
+ int rpm_min = fan_data->speed[0].rpm;
+ int rpm_max = fan_data->speed[fan_data->num_speed - 1].rpm;
+
+ return (rpm - rpm_min) / DIV_ROUND_UP((rpm_max - rpm_min), 255);
+}
+
+static ssize_t show_pwm(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
+ int rpm;
+ int ret;
+
+ ret = ctrl_to_rpm(fan_data, fan_data->ctrl_val, &rpm);
+ if (ret)
+ return ret;
+
+ return sprintf(buf, "%d\n", rpm_to_pwm(fan_data, rpm));
+}
+
+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 ctrl_val;
+ int ret = count;
+
+ if (strict_strtoul(buf, 10, &pwm) || pwm > 255)
+ return -EINVAL;
+
+ mutex_lock(&fan_data->lock);
+
+ if (fan_data->pwm_enable != 1) {
+ ret = -EPERM;
+ goto exit_unlock;
+ }
+
+ ctrl_val = rpm_to_ctrl(fan_data, pwm_to_rpm(fan_data, (u8) pwm));
+ if (ctrl_val != fan_data->ctrl_val)
+ set_fan_ctrl(fan_data, ctrl_val);
+
+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;
+ int ctrl_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) {
+ ctrl_val = fan_data->speed[fan_data->num_speed - 1].ctrl_val;
+ if (ctrl_val != fan_data->ctrl_val)
+ set_fan_ctrl(fan_data, ctrl_val);
+ }
+
+ 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(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
+ int ret;
+ int rpm;
+
+ ret = ctrl_to_rpm(fan_data, fan_data->ctrl_val, &rpm);
+ if (ret < 0)
+ return ret;
+
+ return sprintf(buf, "%d\n", rpm);
+}
+
+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_input, S_IRUGO, show_rpm, NULL);
+
+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,
+ NULL
+};
+
+static const struct attribute_group gpio_fan_ctrl_group = {
+ .attrs = gpio_fan_ctrl_attributes,
+};
+
+static int __devinit 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->platform_set_ctrl = pdata->set_ctrl;
+ fan_data->num_speed = pdata->num_speed;
+ fan_data->speed = pdata->speed;
+ fan_data->pwm_enable = 1; /* Enable manual fan speed control. */
+ if (pdata->get_ctrl)
+ fan_data->ctrl_val = pdata->get_ctrl(num_ctrl, ctrl);
+ else
+ fan_data->ctrl_val = __get_fan_ctrl(fan_data);
+
+ return 0;
+
+err_free_gpio:
+ for (i = i - 1; i >= 0; i--)
+ gpio_free(ctrl[i]);
+
+ return err;
+}
+
+static void __devexit 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 = 0;
+ 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) {
+ if (!pdata->num_speed || !pdata->speed) {
+ 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:
+ fan_ctrl_free(fan_data);
+err_free_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;
+}
+
+static struct platform_driver gpio_fan_driver = {
+ .probe = gpio_fan_probe,
+ .remove = __devexit_p(gpio_fan_remove),
+ .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);
+ return;
+}
+
+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");
diff --git a/include/linux/gpio-fan.h b/include/linux/gpio-fan.h
new file mode 100644
index 0000000..58f0930
--- /dev/null
+++ b/include/linux/gpio-fan.h
@@ -0,0 +1,43 @@
+/*
+ * 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;
+ /*
+ * This functions can be supplied if some specific operations are
+ * required to get/set a fan control (handle a latch enable GPIO,
+ * prevent from writing some transitional control value, etc...)
+ */
+ int (*get_ctrl)(int num_ctrl, unsigned *ctrl);
+ void (*set_ctrl)(int num_ctrl, unsigned *ctrl, int ctrl_val);
+};
+
+#endif /* __LINUX_GPIO_FAN_H */
--
1.6.3.1