drivers/base/auxiliary.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2019-2020 Intel Corporation
  *
  * Please see Documentation/driver-api/auxiliary_bus.rst for more information.
  */

 #define pr_fmt(fmt) "%s:%s: " fmt, KBUILD_MODNAME, __func__

 #include <linux/device.h>
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/pm_domain.h>
 #include <linux/pm_runtime.h>
 #include <linux/string.h>
 #include <linux/auxiliary_bus.h>

 static const struct auxiliary_device_id *auxiliary_match_id(const struct auxiliary_device_id *id,
 							    const struct auxiliary_device *auxdev)
 {
 	for (; id->name[0]; id++) {
 		const char *p = strrchr(dev_name(&auxdev->dev), '.');
 		int match_size;

 		if (!p)
 			continue;
 		match_size = p - dev_name(&auxdev->dev);

 		/* use dev_name(&auxdev->dev) prefix before last '.' char to match to */
 		if (strlen(id->name) == match_size &&
 		    !strncmp(dev_name(&auxdev->dev), id->name, match_size))
 			return id;
 	}
 	return NULL;
 }

 static int auxiliary_match(struct device *dev, struct device_driver *drv)
 {
 	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
 	struct auxiliary_driver *auxdrv = to_auxiliary_drv(drv);

 	return !!auxiliary_match_id(auxdrv->id_table, auxdev);
 }

 static int auxiliary_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
 	const char *name, *p;

 	name = dev_name(dev);
 	p = strrchr(name, '.');

 	return add_uevent_var(env, "MODALIAS=%s%.*s", AUXILIARY_MODULE_PREFIX,
 			      (int)(p - name), name);
 }

 static const struct dev_pm_ops auxiliary_dev_pm_ops = {
 	SET_RUNTIME_PM_OPS(pm_generic_runtime_suspend, pm_generic_runtime_resume, NULL)
 	SET_SYSTEM_SLEEP_PM_OPS(pm_generic_suspend, pm_generic_resume)
 };

 static int auxiliary_bus_probe(struct device *dev)
 {
 	struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver);
 	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
 	int ret;

 	ret = dev_pm_domain_attach(dev, true);
 	if (ret) {
 		dev_warn(dev, "Failed to attach to PM Domain : %d\n", ret);
 		return ret;
 	}

 	ret = auxdrv->probe(auxdev, auxiliary_match_id(auxdrv->id_table, auxdev));
 	if (ret)
 		dev_pm_domain_detach(dev, true);

 	return ret;
 }

 static int auxiliary_bus_remove(struct device *dev)
 {
 	struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver);
 	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);

 	if (auxdrv->remove)
 		auxdrv->remove(auxdev);
 	dev_pm_domain_detach(dev, true);

 	return 0;
 }

 static void auxiliary_bus_shutdown(struct device *dev)
 {
 	struct auxiliary_driver *auxdrv = NULL;
 	struct auxiliary_device *auxdev;

 	if (dev->driver) {
 		auxdrv = to_auxiliary_drv(dev->driver);
 		auxdev = to_auxiliary_dev(dev);
 	}

 	if (auxdrv && auxdrv->shutdown)
 		auxdrv->shutdown(auxdev);
 }

 static struct bus_type auxiliary_bus_type = {
 	.name = "auxiliary",
 	.probe = auxiliary_bus_probe,
 	.remove = auxiliary_bus_remove,
 	.shutdown = auxiliary_bus_shutdown,
 	.match = auxiliary_match,
 	.uevent = auxiliary_uevent,
 	.pm = &auxiliary_dev_pm_ops,
 };

 /**
  * auxiliary_device_init - check auxiliary_device and initialize
  * @auxdev: auxiliary device struct
  *
  * This is the first step in the two-step process to register an
  * auxiliary_device.
  *
  * When this function returns an error code, then the device_initialize will
  * *not* have been performed, and the caller will be responsible to free any
  * memory allocated for the auxiliary_device in the error path directly.
  *
  * It returns 0 on success.  On success, the device_initialize has been
  * performed.  After this point any error unwinding will need to include a call
  * to auxiliary_device_uninit().  In this post-initialize error scenario, a call
  * to the device's .release callback will be triggered, and all memory clean-up
  * is expected to be handled there.
  */
 int auxiliary_device_init(struct auxiliary_device *auxdev)
 {
 	struct device *dev = &auxdev->dev;

 	if (!dev->parent) {
 		pr_err("auxiliary_device has a NULL dev->parent\n");
 		return -EINVAL;
 	}

 	if (!auxdev->name) {
 		pr_err("auxiliary_device has a NULL name\n");
 		return -EINVAL;
 	}

 	dev->bus = &auxiliary_bus_type;
 	device_initialize(&auxdev->dev);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(auxiliary_device_init);

 /**
  * __auxiliary_device_add - add an auxiliary bus device
  * @auxdev: auxiliary bus device to add to the bus
  * @modname: name of the parent device's driver module
  *
  * This is the second step in the two-step process to register an
  * auxiliary_device.
  *
  * This function must be called after a successful call to
  * auxiliary_device_init(), which will perform the device_initialize.  This
  * means that if this returns an error code, then a call to
  * auxiliary_device_uninit() must be performed so that the .release callback
  * will be triggered to free the memory associated with the auxiliary_device.
  *
  * The expectation is that users will call the "auxiliary_device_add" macro so
  * that the caller's KBUILD_MODNAME is automatically inserted for the modname
  * parameter.  Only if a user requires a custom name would this version be
  * called directly.
  */
 int __auxiliary_device_add(struct auxiliary_device *auxdev, const char *modname)
 {
 	struct device *dev = &auxdev->dev;
 	int ret;

 	if (!modname) {
 		dev_err(dev, "auxiliary device modname is NULL\n");
 		return -EINVAL;
 	}

 	ret = dev_set_name(dev, "%s.%s.%d", modname, auxdev->name, auxdev->id);
 	if (ret) {
 		dev_err(dev, "auxiliary device dev_set_name failed: %d\n", ret);
 		return ret;
 	}

 	ret = device_add(dev);
 	if (ret)
 		dev_err(dev, "adding auxiliary device failed!: %d\n", ret);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(__auxiliary_device_add);

 /**
  * auxiliary_find_device - auxiliary device iterator for locating a particular device.
  * @start: Device to begin with
  * @data: Data to pass to match function
  * @match: Callback function to check device
  *
  * This function returns a reference to a device that is 'found'
  * for later use, as determined by the @match callback.
  *
  * The callback should return 0 if the device doesn't match and non-zero
  * if it does.  If the callback returns non-zero, this function will
  * return to the caller and not iterate over any more devices.
  */
 struct auxiliary_device *auxiliary_find_device(struct device *start,
 					       const void *data,
 					       int (*match)(struct device *dev, const void *data))
 {
 	struct device *dev;

 	dev = bus_find_device(&auxiliary_bus_type, start, data, match);
 	if (!dev)
 		return NULL;

 	return to_auxiliary_dev(dev);
 }
 EXPORT_SYMBOL_GPL(auxiliary_find_device);

 /**
  * __auxiliary_driver_register - register a driver for auxiliary bus devices
  * @auxdrv: auxiliary_driver structure
  * @owner: owning module/driver
  * @modname: KBUILD_MODNAME for parent driver
  */
 int __auxiliary_driver_register(struct auxiliary_driver *auxdrv,
 				struct module *owner, const char *modname)
 {
 	if (WARN_ON(!auxdrv->probe) || WARN_ON(!auxdrv->id_table))
 		return -EINVAL;

 	if (auxdrv->name)
 		auxdrv->driver.name = kasprintf(GFP_KERNEL, "%s.%s", modname,
 						auxdrv->name);
 	else
 		auxdrv->driver.name = kasprintf(GFP_KERNEL, "%s", modname);
 	if (!auxdrv->driver.name)
 		return -ENOMEM;

 	auxdrv->driver.owner = owner;
 	auxdrv->driver.bus = &auxiliary_bus_type;
 	auxdrv->driver.mod_name = modname;

 	return driver_register(&auxdrv->driver);
 }
 EXPORT_SYMBOL_GPL(__auxiliary_driver_register);

 /**
  * auxiliary_driver_unregister - unregister a driver
  * @auxdrv: auxiliary_driver structure
  */
 void auxiliary_driver_unregister(struct auxiliary_driver *auxdrv)
 {
 	driver_unregister(&auxdrv->driver);
 	kfree(auxdrv->driver.name);
 }
 EXPORT_SYMBOL_GPL(auxiliary_driver_unregister);

 static int __init auxiliary_bus_init(void)
 {
 	return bus_register(&auxiliary_bus_type);
 }

 static void __exit auxiliary_bus_exit(void)
 {
 	bus_unregister(&auxiliary_bus_type);
 }

 module_init(auxiliary_bus_init);
 module_exit(auxiliary_bus_exit);

 MODULE_LICENSE("GPL v2");
 MODULE_DESCRIPTION("Auxiliary Bus");
 MODULE_AUTHOR("David Ertman <david.m.ertman@intel.com>");
 MODULE_AUTHOR("Kiran Patil <kiran.patil@intel.com>");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (c) 2019-2020 Intel Corporation
	*
	* Please see Documentation/driver-api/auxiliary_bus.rst for more information.
	*/

	#define pr_fmt(fmt) "%s:%s: " fmt, KBUILD_MODNAME, __func__

	#include <linux/device.h>
	#include <linux/init.h>
	#include <linux/slab.h>
	#include <linux/module.h>
	#include <linux/pm_domain.h>
	#include <linux/pm_runtime.h>
	#include <linux/string.h>
	#include <linux/auxiliary_bus.h>

	static const struct auxiliary_device_id auxiliary_match_id(const struct auxiliary_device_id id,
	const struct auxiliary_device *auxdev)
	{
	for (; id->name[0]; id++) {
	const char *p = strrchr(dev_name(&auxdev->dev), '.');
	int match_size;

	if (!p)
	continue;
	match_size = p - dev_name(&auxdev->dev);

	/* use dev_name(&auxdev->dev) prefix before last '.' char to match to */
	if (strlen(id->name) == match_size &&
	!strncmp(dev_name(&auxdev->dev), id->name, match_size))
	return id;
	}
	return NULL;
	}

	static int auxiliary_match(struct device dev, struct device_driver drv)
	{
	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
	struct auxiliary_driver *auxdrv = to_auxiliary_drv(drv);

	return !!auxiliary_match_id(auxdrv->id_table, auxdev);
	}

	static int auxiliary_uevent(struct device dev, struct kobj_uevent_env env)
	{
	const char name, p;

	name = dev_name(dev);
	p = strrchr(name, '.');

	return add_uevent_var(env, "MODALIAS=%s%.*s", AUXILIARY_MODULE_PREFIX,
	(int)(p - name), name);
	}

	static const struct dev_pm_ops auxiliary_dev_pm_ops = {
	SET_RUNTIME_PM_OPS(pm_generic_runtime_suspend, pm_generic_runtime_resume, NULL)
	SET_SYSTEM_SLEEP_PM_OPS(pm_generic_suspend, pm_generic_resume)
	};

	static int auxiliary_bus_probe(struct device *dev)
	{
	struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver);
	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
	int ret;

	ret = dev_pm_domain_attach(dev, true);
	if (ret) {
	dev_warn(dev, "Failed to attach to PM Domain : %d\n", ret);
	return ret;
	}

	ret = auxdrv->probe(auxdev, auxiliary_match_id(auxdrv->id_table, auxdev));
	if (ret)
	dev_pm_domain_detach(dev, true);

	return ret;
	}

	static int auxiliary_bus_remove(struct device *dev)
	{
	struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver);
	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);

	if (auxdrv->remove)
	auxdrv->remove(auxdev);
	dev_pm_domain_detach(dev, true);

	return 0;
	}

	static void auxiliary_bus_shutdown(struct device *dev)
	{
	struct auxiliary_driver *auxdrv = NULL;
	struct auxiliary_device *auxdev;

	if (dev->driver) {
	auxdrv = to_auxiliary_drv(dev->driver);
	auxdev = to_auxiliary_dev(dev);
	}

	if (auxdrv && auxdrv->shutdown)
	auxdrv->shutdown(auxdev);
	}

	static struct bus_type auxiliary_bus_type = {
	.name = "auxiliary",
	.probe = auxiliary_bus_probe,
	.remove = auxiliary_bus_remove,
	.shutdown = auxiliary_bus_shutdown,
	.match = auxiliary_match,
	.uevent = auxiliary_uevent,
	.pm = &auxiliary_dev_pm_ops,
	};

	/**
	* auxiliary_device_init - check auxiliary_device and initialize
	* @auxdev: auxiliary device struct
	*
	* This is the first step in the two-step process to register an
	* auxiliary_device.
	*
	* When this function returns an error code, then the device_initialize will
	* not have been performed, and the caller will be responsible to free any
	* memory allocated for the auxiliary_device in the error path directly.
	*
	* It returns 0 on success. On success, the device_initialize has been
	* performed. After this point any error unwinding will need to include a call
	* to auxiliary_device_uninit(). In this post-initialize error scenario, a call
	* to the device's .release callback will be triggered, and all memory clean-up
	* is expected to be handled there.
	*/
	int auxiliary_device_init(struct auxiliary_device *auxdev)
	{
	struct device *dev = &auxdev->dev;

	if (!dev->parent) {
	pr_err("auxiliary_device has a NULL dev->parent\n");
	return -EINVAL;
	}

	if (!auxdev->name) {
	pr_err("auxiliary_device has a NULL name\n");
	return -EINVAL;
	}

	dev->bus = &auxiliary_bus_type;
	device_initialize(&auxdev->dev);
	return 0;
	}
	EXPORT_SYMBOL_GPL(auxiliary_device_init);

	/**
	* __auxiliary_device_add - add an auxiliary bus device
	* @auxdev: auxiliary bus device to add to the bus
	* @modname: name of the parent device's driver module
	*
	* This is the second step in the two-step process to register an
	* auxiliary_device.
	*
	* This function must be called after a successful call to
	* auxiliary_device_init(), which will perform the device_initialize. This
	* means that if this returns an error code, then a call to
	* auxiliary_device_uninit() must be performed so that the .release callback
	* will be triggered to free the memory associated with the auxiliary_device.
	*
	* The expectation is that users will call the "auxiliary_device_add" macro so
	* that the caller's KBUILD_MODNAME is automatically inserted for the modname
	* parameter. Only if a user requires a custom name would this version be
	* called directly.
	*/
	int __auxiliary_device_add(struct auxiliary_device auxdev, const char modname)
	{
	struct device *dev = &auxdev->dev;
	int ret;

	if (!modname) {
	dev_err(dev, "auxiliary device modname is NULL\n");
	return -EINVAL;
	}

	ret = dev_set_name(dev, "%s.%s.%d", modname, auxdev->name, auxdev->id);
	if (ret) {
	dev_err(dev, "auxiliary device dev_set_name failed: %d\n", ret);
	return ret;
	}

	ret = device_add(dev);
	if (ret)
	dev_err(dev, "adding auxiliary device failed!: %d\n", ret);

	return ret;
	}
	EXPORT_SYMBOL_GPL(__auxiliary_device_add);

	/**
	* auxiliary_find_device - auxiliary device iterator for locating a particular device.
	* @start: Device to begin with
	* @data: Data to pass to match function
	* @match: Callback function to check device
	*
	* This function returns a reference to a device that is 'found'
	* for later use, as determined by the @match callback.
	*
	* The callback should return 0 if the device doesn't match and non-zero
	* if it does. If the callback returns non-zero, this function will
	* return to the caller and not iterate over any more devices.
	*/
	struct auxiliary_device auxiliary_find_device(struct device start,
	const void *data,
	int (match)(struct device dev, const void *data))
	{
	struct device *dev;

	dev = bus_find_device(&auxiliary_bus_type, start, data, match);
	if (!dev)
	return NULL;

	return to_auxiliary_dev(dev);
	}
	EXPORT_SYMBOL_GPL(auxiliary_find_device);

	/**
	* __auxiliary_driver_register - register a driver for auxiliary bus devices
	* @auxdrv: auxiliary_driver structure
	* @owner: owning module/driver
	* @modname: KBUILD_MODNAME for parent driver
	*/
	int __auxiliary_driver_register(struct auxiliary_driver *auxdrv,
	struct module owner, const char modname)
	{
	if (WARN_ON(!auxdrv->probe) \|\| WARN_ON(!auxdrv->id_table))
	return -EINVAL;

	if (auxdrv->name)
	auxdrv->driver.name = kasprintf(GFP_KERNEL, "%s.%s", modname,
	auxdrv->name);
	else
	auxdrv->driver.name = kasprintf(GFP_KERNEL, "%s", modname);
	if (!auxdrv->driver.name)
	return -ENOMEM;

	auxdrv->driver.owner = owner;
	auxdrv->driver.bus = &auxiliary_bus_type;
	auxdrv->driver.mod_name = modname;

	return driver_register(&auxdrv->driver);
	}
	EXPORT_SYMBOL_GPL(__auxiliary_driver_register);

	/**
	* auxiliary_driver_unregister - unregister a driver
	* @auxdrv: auxiliary_driver structure
	*/
	void auxiliary_driver_unregister(struct auxiliary_driver *auxdrv)
	{
	driver_unregister(&auxdrv->driver);
	kfree(auxdrv->driver.name);
	}
	EXPORT_SYMBOL_GPL(auxiliary_driver_unregister);

	static int __init auxiliary_bus_init(void)
	{
	return bus_register(&auxiliary_bus_type);
	}

	static void __exit auxiliary_bus_exit(void)
	{
	bus_unregister(&auxiliary_bus_type);
	}

	module_init(auxiliary_bus_init);
	module_exit(auxiliary_bus_exit);

	MODULE_LICENSE("GPL v2");
	MODULE_DESCRIPTION("Auxiliary Bus");
	MODULE_AUTHOR("David Ertman <david.m.ertman@intel.com>");
	MODULE_AUTHOR("Kiran Patil <kiran.patil@intel.com>");