path: root/drivers/hwmon/hwmon.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * hwmon.c - part of lm_sensors, Linux kernel modules for hardware monitoring
 *
 * This file defines the sysfs class "hwmon", for use by sensors drivers.
 *
 * Copyright (C) 2005 Mark M. Hoffman <mhoffman@lightlink.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/bitops.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/gfp.h>
#include <linux/hwmon.h>
#include <linux/idr.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/thermal.h>

#define CREATE_TRACE_POINTS
#include <trace/events/hwmon.h>

#define HWMON_ID_PREFIX "hwmon"
#define HWMON_ID_FORMAT HWMON_ID_PREFIX "%d"

struct hwmon_device {
	const char *name;
	struct device dev;
	const struct hwmon_chip_info *chip;
	struct list_head tzdata;
	struct attribute_group group;
	const struct attribute_group **groups;
};

#define to_hwmon_device(d) container_of(d, struct hwmon_device, dev)

#define MAX_SYSFS_ATTR_NAME_LENGTH	32

struct hwmon_device_attribute {
	struct device_attribute dev_attr;
	const struct hwmon_ops *ops;
	enum hwmon_sensor_types type;
	u32 attr;
	int index;
	char name[MAX_SYSFS_ATTR_NAME_LENGTH];
};

#define to_hwmon_attr(d) \
	container_of(d, struct hwmon_device_attribute, dev_attr)
#define to_dev_attr(a) container_of(a, struct device_attribute, attr)

/*
 * Thermal zone information
 */
struct hwmon_thermal_data {
	struct list_head node;		/* hwmon tzdata list entry */
	struct device *dev;		/* Reference to hwmon device */
	int index;			/* sensor index */
	struct thermal_zone_device *tzd;/* thermal zone device */
};

static ssize_t
name_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	return sprintf(buf, "%s\n", to_hwmon_device(dev)->name);
}
static DEVICE_ATTR_RO(name);

static struct attribute *hwmon_dev_attrs[] = {
	&dev_attr_name.attr,
	NULL
};

static umode_t hwmon_dev_name_is_visible(struct kobject *kobj,
					 struct attribute *attr, int n)
{
	struct device *dev = container_of(kobj, struct device, kobj);

	if (to_hwmon_device(dev)->name == NULL)
		return 0;

	return attr->mode;
}

static const struct attribute_group hwmon_dev_attr_group = {
	.attrs		= hwmon_dev_attrs,
	.is_visible	= hwmon_dev_name_is_visible,
};

static const struct attribute_group *hwmon_dev_attr_groups[] = {
	&hwmon_dev_attr_group,
	NULL
};

static void hwmon_free_attrs(struct attribute **attrs)
{
	int i;

	for (i = 0; attrs[i]; i++) {
		struct device_attribute *dattr = to_dev_attr(attrs[i]);
		struct hwmon_device_attribute *hattr = to_hwmon_attr(dattr);

		kfree(hattr);
	}
	kfree(attrs);
}

static void hwmon_dev_release(struct device *dev)
{
	struct hwmon_device *hwdev = to_hwmon_device(dev);

	if (hwdev->group.attrs)
		hwmon_free_attrs(hwdev->group.attrs);
	kfree(hwdev->groups);
	kfree(hwdev);
}

static struct class hwmon_class = {
	.name = "hwmon",
	.owner = THIS_MODULE,
	.dev_groups = hwmon_dev_attr_groups,
	.dev_release = hwmon_dev_release,
};

static DEFINE_IDA(hwmon_ida);

/* Thermal zone handling */

/*
 * The complex conditional is necessary to avoid a cyclic dependency
 * between hwmon and thermal_sys modules.
 */
#ifdef CONFIG_THERMAL_OF
static int hwmon_thermal_get_temp(void *data, int *temp)
{
	struct hwmon_thermal_data *tdata = data;
	struct hwmon_device *hwdev = to_hwmon_device(tdata->dev);
	int ret;
	long t;

	ret = hwdev->chip->ops->read(tdata->dev, hwmon_temp, hwmon_temp_input,
				     tdata->index, &t);
	if (ret < 0)
		return ret;

	*temp = t;

	return 0;
}

static const struct thermal_zone_of_device_ops hwmon_thermal_ops = {
	.get_temp = hwmon_thermal_get_temp,
};

static void hwmon_thermal_remove_sensor(void *data)
{
	list_del(data);
}

static int hwmon_thermal_add_sensor(struct device *dev, int index)
{
	struct hwmon_device *hwdev = to_hwmon_device(dev);
	struct hwmon_thermal_data *tdata;
	struct thermal_zone_device *tzd;
	int err;

	tdata = devm_kzalloc(dev, sizeof(*tdata), GFP_KERNEL);
	if (!tdata)
		return -ENOMEM;

	tdata->dev = dev;
	tdata->index = index;

	tzd = devm_thermal_zone_of_sensor_register(dev, index, tdata,
						   &hwmon_thermal_ops);
	if (IS_ERR(tzd)) {
		if (PTR_ERR(tzd) != -ENODEV)
			return PTR_ERR(tzd);
		dev_info(dev, "temp%d_input not attached to any thermal zone\n",
			 index + 1);
		devm_kfree(dev, tdata);
		return 0;
	}

	err = devm_add_action(dev, hwmon_thermal_remove_sensor, &tdata->node);
	if (err)
		return err;

	tdata->tzd = tzd;
	list_add(&tdata->node, &hwdev->tzdata);

	return 0;
}

static int hwmon_thermal_register_sensors(struct device *dev)
{
	struct hwmon_device *hwdev = to_hwmon_device(dev);