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");