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/property.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;
	const char *label;
	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 ssize_t
label_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	return sysfs_emit(buf, "%s\n", to_hwmon_device(dev)->label);
}
static DEVICE_ATTR_RO(label);

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

static umode_t hwmon_dev_attr_is_visible(struct kobject *kobj,
					 struct attribute *attr, int n)
{
	struct device *dev = kobj_to_dev(kobj);
	struct hwmon_device *hdev = to_hwmon_device(dev);

	if (attr == &dev_attr_name.attr && hdev->name == NULL)
		return 0;

	if (attr == &dev_attr_label.attr && hdev->label == NULL)
		return 0;

	return attr->mode;
}

static const struct attribute_group hwmon_dev_attr_group = {
	.attrs		= hwmon_dev_attrs,
	.is_visible	= hwmon_dev_attr_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->label);
	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(struct thermal_zone_device *tz, int *temp)
{
	struct