// SPDX-License-Identifier: GPL-2.0
/*
 * The class-specific portions of the driver model
 *
 * Copyright (c) 2001-2003 Patrick Mochel <mochel@osdl.org>
 * Copyright (c) 2004-2009 Greg Kroah-Hartman <gregkh@suse.de>
 * Copyright (c) 2008-2009 Novell Inc.
 * Copyright (c) 2012-2019 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 * Copyright (c) 2012-2019 Linux Foundation
 *
 * See Documentation/driver-api/driver-model/ for more information.
 */

#ifndef _DEVICE_CLASS_H_
#define _DEVICE_CLASS_H_

#include <linux/kobject.h>
#include <linux/klist.h>
#include <linux/pm.h>
#include <linux/device/bus.h>

struct device;
struct fwnode_handle;

/**
 * struct class - device classes
 * @name:       Name of the class.
 * @class_groups: Default attributes of this class.
 * @dev_groups: Default attributes of the devices that belong to the class.
 * @dev_uevent: Called when a device is added, removed from this class, or a
 *              few other things that generate uevents to add the environment
 *              variables.
 * @devnode:    Callback to provide the devtmpfs.
 * @class_release: Called to release this class.
 * @dev_release: Called to release the device.
 * @shutdown_pre: Called at shut-down time before driver shutdown.
 * @ns_type:    Callbacks so sysfs can detemine namespaces.
 * @namespace:  Namespace of the device belongs to this class.
 * @get_ownership: Allows class to specify uid/gid of the sysfs directories
 *              for the devices belonging to the class. Usually tied to
 *              device's namespace.
 * @pm:         The default device power management operations of this class.
 *
 * A class is a higher-level view of a device that abstracts out low-level
 * implementation details. Drivers may see a SCSI disk or an ATA disk, but,
 * at the class level, they are all simply disks. Classes allow user space
 * to work with devices based on what they do, rather than how they are
 * connected or how they work.
 */
struct class {
        const char              *name;

        const struct attribute_group    **class_groups;
        const struct attribute_group    **dev_groups;

        int (*dev_uevent)(const struct device *dev, struct kobj_uevent_env *env);
        char *(*devnode)(const struct device *dev, umode_t *mode);

        void (*class_release)(const struct class *class);
        void (*dev_release)(struct device *dev);

        int (*shutdown_pre)(struct device *dev);

        const struct kobj_ns_type_operations *ns_type;
        const struct ns_common *(*namespace)(const struct device *dev);

        void (*get_ownership)(const struct device *dev, kuid_t *uid, kgid_t *gid);

        const struct dev_pm_ops *pm;
};

struct class_dev_iter {
        struct klist_iter               ki;
        const struct device_type        *type;
        struct subsys_private           *sp;
};

int __must_check class_register(const struct class *class);
void class_unregister(const struct class *class);
bool class_is_registered(const struct class *class);

struct class_compat;
struct class_compat *class_compat_register(const char *name);
void class_compat_unregister(struct class_compat *cls);
int class_compat_create_link(struct class_compat *cls, struct device *dev);
void class_compat_remove_link(struct class_compat *cls, struct device *dev);

void class_dev_iter_init(struct class_dev_iter *iter, const struct class *class,
                         const struct device *start, const struct device_type *type);
struct device *class_dev_iter_next(struct class_dev_iter *iter);
void class_dev_iter_exit(struct class_dev_iter *iter);

int class_for_each_device(const struct class *class, const struct device *start,
                          void *data, device_iter_t fn);
struct device *class_find_device(const struct class *class, const struct device *start,
                                 const void *data, device_match_t match);

/**
 * class_find_device_by_name - device iterator for locating a particular device
 * of a specific name.
 * @class: class type
 * @name: name of the device to match
 */
static inline struct device *class_find_device_by_name(const struct class *class,
                                                       const char *name)
{
        return class_find_device(class, NULL, name, device_match_name);
}

/**
 * class_find_device_by_of_node : device iterator for locating a particular device
 * matching the of_node.
 * @class: class type
 * @np: of_node of the device to match.
 */
static inline struct device *class_find_device_by_of_node(const struct class *class,
                                                          const struct device_node *np)
{
        return class_find_device(class, NULL, np, device_match_of_node);
}

/**
 * class_find_device_by_fwnode : device iterator for locating a particular device
 * matching the fwnode.
 * @class: class type
 * @fwnode: fwnode of the device to match.
 */
static inline struct device *class_find_device_by_fwnode(const struct class *class,
                                                         const struct fwnode_handle *fwnode)
{
        return class_find_device(class, NULL, fwnode, device_match_fwnode);
}

/**
 * class_find_device_by_devt : device iterator for locating a particular device
 * matching the device type.
 * @class: class type
 * @devt: device type of the device to match.
 */
static inline struct device *class_find_device_by_devt(const struct class *class,
                                                       dev_t devt)
{
        return class_find_device(class, NULL, &devt, device_match_devt);
}

#ifdef CONFIG_ACPI
struct acpi_device;
/**
 * class_find_device_by_acpi_dev : device iterator for locating a particular
 * device matching the ACPI_COMPANION device.
 * @class: class type
 * @adev: ACPI_COMPANION device to match.
 */
static inline struct device *class_find_device_by_acpi_dev(const struct class *class,
                                                           const struct acpi_device *adev)
{
        return class_find_device(class, NULL, adev, device_match_acpi_dev);
}
#else
static inline struct device *class_find_device_by_acpi_dev(const struct class *class,
                                                           const void *adev)
{
        return NULL;
}
#endif

struct class_attribute {
        struct attribute attr;
        ssize_t (*show)(const struct class *class, const struct class_attribute *attr,
                        char *buf);
        ssize_t (*store)(const struct class *class, const struct class_attribute *attr,
                         const char *buf, size_t count);
};

#define CLASS_ATTR_RW(_name) \
        struct class_attribute class_attr_##_name = __ATTR_RW(_name)
#define CLASS_ATTR_RO(_name) \
        struct class_attribute class_attr_##_name = __ATTR_RO(_name)
#define CLASS_ATTR_WO(_name) \
        struct class_attribute class_attr_##_name = __ATTR_WO(_name)

int __must_check class_create_file_ns(const struct class *class, const struct class_attribute *attr,
                                      const struct ns_common *ns);
void class_remove_file_ns(const struct class *class, const struct class_attribute *attr,
                          const struct ns_common *ns);

static inline int __must_check class_create_file(const struct class *class,
                                                 const struct class_attribute *attr)
{
        return class_create_file_ns(class, attr, NULL);
}

static inline void class_remove_file(const struct class *class,
                                     const struct class_attribute *attr)
{
        class_remove_file_ns(class, attr, NULL);
}

/* Simple class attribute that is just a static string */
struct class_attribute_string {
        struct class_attribute attr;
        char *str;
};

/* Currently read-only only */
#define _CLASS_ATTR_STRING(_name, _mode, _str) \
        { __ATTR(_name, _mode, show_class_attr_string, NULL), _str }
#define CLASS_ATTR_STRING(_name, _mode, _str) \
        struct class_attribute_string class_attr_##_name = \
                _CLASS_ATTR_STRING(_name, _mode, _str)

ssize_t show_class_attr_string(const struct class *class, const struct class_attribute *attr,
                               char *buf);

struct class_interface {
        struct list_head        node;
        const struct class      *class;

        int (*add_dev)          (struct device *dev);
        void (*remove_dev)      (struct device *dev);
};

int __must_check class_interface_register(struct class_interface *);
void class_interface_unregister(struct class_interface *);

struct class * __must_check class_create(const char *name);
void class_destroy(const struct class *cls);

#endif  /* _DEVICE_CLASS_H_ */