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path: root/drivers/hwmon/gpio-fan.c
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-rw-r--r--drivers/hwmon/gpio-fan.c597
1 files changed, 597 insertions, 0 deletions
diff --git a/drivers/hwmon/gpio-fan.c b/drivers/hwmon/gpio-fan.c
new file mode 100644
index 000000000..ba408942d
--- /dev/null
+++ b/drivers/hwmon/gpio-fan.c
@@ -0,0 +1,597 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * gpio-fan.c - Hwmon driver for fans connected to GPIO lines.
+ *
+ * Copyright (C) 2010 LaCie
+ *
+ * Author: Simon Guinot <sguinot@lacie.com>
+ */
+
+#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/consumer.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/thermal.h>
+
+struct gpio_fan_speed {
+ int rpm;
+ int ctrl_val;
+};
+
+struct gpio_fan_data {
+ struct device *dev;
+ struct device *hwmon_dev;
+ /* Cooling device if any */
+ struct thermal_cooling_device *cdev;
+ struct mutex lock; /* lock GPIOs operations. */
+ int num_gpios;
+ struct gpio_desc **gpios;
+ int num_speed;
+ struct gpio_fan_speed *speed;
+ int speed_index;
+ int resume_speed;
+ bool pwm_enable;
+ struct gpio_desc *alarm_gpio;
+ 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->hwmon_dev->kobj, NULL, "fan1_alarm");
+ kobject_uevent(&fan_data->hwmon_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 fan1_alarm_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%d\n",
+ gpiod_get_value_cansleep(fan_data->alarm_gpio));
+}
+
+static DEVICE_ATTR_RO(fan1_alarm);
+
+static int fan_alarm_init(struct gpio_fan_data *fan_data)
+{
+ int alarm_irq;
+ struct device *dev = fan_data->dev;
+
+ /*
+ * If the alarm GPIO don't support interrupts, just leave
+ * without initializing the fail notification support.
+ */
+ alarm_irq = gpiod_to_irq(fan_data->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);
+ return devm_request_irq(dev, alarm_irq, fan_alarm_irq_handler,
+ IRQF_SHARED, "GPIO fan alarm", fan_data);
+}
+
+/*
+ * 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_gpios; i++)
+ gpiod_set_value_cansleep(fan_data->gpios[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_gpios; i++) {
+ int value;
+
+ value = gpiod_get_value_cansleep(fan_data->gpios[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->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 pwm1_show(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 pwm1_store(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 pwm1_enable_show(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 pwm1_enable_store(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 pwm1_mode_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "0\n");
+}
+
+static ssize_t fan1_min_show(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 fan1_max_show(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 fan1_input_show(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_RW(pwm1);
+static DEVICE_ATTR_RW(pwm1_enable);
+static DEVICE_ATTR_RO(pwm1_mode);
+static DEVICE_ATTR_RO(fan1_min);
+static DEVICE_ATTR_RO(fan1_max);
+static DEVICE_ATTR_RO(fan1_input);
+static DEVICE_ATTR(fan1_target, 0644, fan1_input_show, set_rpm);
+
+static umode_t gpio_fan_is_visible(struct kobject *kobj,
+ struct attribute *attr, int index)
+{
+ struct device *dev = kobj_to_dev(kobj);
+ struct gpio_fan_data *data = dev_get_drvdata(dev);
+
+ if (index == 0 && !data->alarm_gpio)
+ return 0;
+ if (index > 0 && !data->gpios)
+ 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)
+{
+ int num_gpios = fan_data->num_gpios;
+ struct gpio_desc **gpios = fan_data->gpios;
+ int i, err;
+
+ for (i = 0; i < num_gpios; i++) {
+ /*
+ * The GPIO descriptors were retrieved with GPIOD_ASIS so here
+ * we set the GPIO into output mode, carefully preserving the
+ * current value by setting it to whatever it is already set
+ * (no surprise changes in default fan speed).
+ */
+ err = gpiod_direction_output(gpios[i],
+ gpiod_get_value_cansleep(gpios[i]));
+ if (err)
+ return err;
+ }
+
+ 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;
+}
+
+static int gpio_fan_get_max_state(struct thermal_cooling_device *cdev,
+ unsigned long *state)
+{
+ struct gpio_fan_data *fan_data = cdev->devdata;
+
+ if (!fan_data)
+ return -EINVAL;
+
+ *state = fan_data->num_speed - 1;
+ return 0;
+}
+
+static int gpio_fan_get_cur_state(struct thermal_cooling_device *cdev,
+ unsigned long *state)
+{
+ struct gpio_fan_data *fan_data = cdev->devdata;
+
+ if (!fan_data)
+ return -EINVAL;
+
+ *state = fan_data->speed_index;
+ return 0;
+}
+
+static int gpio_fan_set_cur_state(struct thermal_cooling_device *cdev,
+ unsigned long state)
+{
+ struct gpio_fan_data *fan_data = cdev->devdata;
+
+ if (!fan_data)
+ return -EINVAL;
+
+ if (state >= fan_data->num_speed)
+ return -EINVAL;
+
+ set_fan_speed(fan_data, state);
+ return 0;
+}
+
+static const struct thermal_cooling_device_ops gpio_fan_cool_ops = {
+ .get_max_state = gpio_fan_get_max_state,
+ .get_cur_state = gpio_fan_get_cur_state,
+ .set_cur_state = gpio_fan_set_cur_state,
+};
+
+/*
+ * Translate OpenFirmware node properties into platform_data
+ */
+static int gpio_fan_get_of_data(struct gpio_fan_data *fan_data)
+{
+ struct gpio_fan_speed *speed;
+ struct device *dev = fan_data->dev;
+ struct device_node *np = dev->of_node;
+ struct gpio_desc **gpios;
+ unsigned i;
+ u32 u;
+ struct property *prop;
+ const __be32 *p;
+
+ /* Alarm GPIO if one exists */
+ fan_data->alarm_gpio = devm_gpiod_get_optional(dev, "alarm", GPIOD_IN);
+ if (IS_ERR(fan_data->alarm_gpio))
+ return PTR_ERR(fan_data->alarm_gpio);
+
+ /* Fill GPIO pin array */
+ fan_data->num_gpios = gpiod_count(dev, NULL);
+ if (fan_data->num_gpios <= 0) {
+ if (fan_data->alarm_gpio)
+ return 0;
+ dev_err(dev, "DT properties empty / missing");
+ return -ENODEV;
+ }
+ gpios = devm_kcalloc(dev,
+ fan_data->num_gpios, sizeof(struct gpio_desc *),
+ GFP_KERNEL);
+ if (!gpios)
+ return -ENOMEM;
+ for (i = 0; i < fan_data->num_gpios; i++) {
+ gpios[i] = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS);
+ if (IS_ERR(gpios[i]))
+ return PTR_ERR(gpios[i]);
+ }
+ fan_data->gpios = gpios;
+
+ /* Get number of RPM/ctrl_val pairs in speed map */
+ prop = of_find_property(np, "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;
+ }
+ fan_data->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_kcalloc(dev,
+ fan_data->num_speed, sizeof(struct gpio_fan_speed),
+ GFP_KERNEL);
+ if (!speed)
+ return -ENOMEM;
+ p = NULL;
+ for (i = 0; i < fan_data->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;
+ }
+ fan_data->speed = speed;
+
+ return 0;
+}
+
+static const struct of_device_id of_gpio_fan_match[] = {
+ { .compatible = "gpio-fan", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, of_gpio_fan_match);
+
+static void gpio_fan_stop(void *data)
+{
+ set_fan_speed(data, 0);
+}
+
+static int gpio_fan_probe(struct platform_device *pdev)
+{
+ int err;
+ struct gpio_fan_data *fan_data;
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+
+ fan_data = devm_kzalloc(dev, sizeof(struct gpio_fan_data),
+ GFP_KERNEL);
+ if (!fan_data)
+ return -ENOMEM;
+
+ fan_data->dev = dev;
+ err = gpio_fan_get_of_data(fan_data);
+ if (err)
+ return err;
+
+ platform_set_drvdata(pdev, fan_data);
+ mutex_init(&fan_data->lock);
+
+ /* Configure control GPIOs if available. */
+ if (fan_data->gpios && fan_data->num_gpios > 0) {
+ if (!fan_data->speed || fan_data->num_speed <= 1)
+ return -EINVAL;
+ err = fan_ctrl_init(fan_data);
+ if (err)
+ return err;
+ err = devm_add_action_or_reset(dev, gpio_fan_stop, fan_data);
+ if (err)
+ return err;
+ }
+
+ /* Make this driver part of hwmon class. */
+ fan_data->hwmon_dev =
+ devm_hwmon_device_register_with_groups(dev,
+ "gpio_fan", fan_data,
+ gpio_fan_groups);
+ if (IS_ERR(fan_data->hwmon_dev))
+ return PTR_ERR(fan_data->hwmon_dev);
+
+ /* Configure alarm GPIO if available. */
+ if (fan_data->alarm_gpio) {
+ err = fan_alarm_init(fan_data);
+ if (err)
+ return err;
+ }
+
+ /* Optional cooling device register for Device tree platforms */
+ fan_data->cdev = devm_thermal_of_cooling_device_register(dev, np,
+ "gpio-fan", fan_data, &gpio_fan_cool_ops);
+
+ dev_info(dev, "GPIO fan initialized\n");
+
+ return 0;
+}
+
+static void gpio_fan_shutdown(struct platform_device *pdev)
+{
+ struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);
+
+ if (fan_data->gpios)
+ set_fan_speed(fan_data, 0);
+}
+
+static int gpio_fan_suspend(struct device *dev)
+{
+ struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
+
+ if (fan_data->gpios) {
+ 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->gpios)
+ set_fan_speed(fan_data, fan_data->resume_speed);
+
+ return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume);
+
+static struct platform_driver gpio_fan_driver = {
+ .probe = gpio_fan_probe,
+ .shutdown = gpio_fan_shutdown,
+ .driver = {
+ .name = "gpio-fan",
+ .pm = pm_sleep_ptr(&gpio_fan_pm),
+ .of_match_table = of_match_ptr(of_gpio_fan_match),
+ },
+};
+
+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");