Driver Core: add class iteration api (fd04897b) · Commits · e / devices / android_kernel_fairphone_FP3

drivers/base/class.c

+133 −0

Original line number	Diff line number	Diff line
		@@ -809,6 +809,139 @@ void class_device_put(struct class_device *class_dev)
		kobject_put(&class_dev->kobj);
		}

		/**
		* class_for_each_device - device iterator
		* @class: the class we're iterating
		* @data: data for the callback
		* @fn: function to be called for each device
		*
		* Iterate over @class's list of devices, and call @fn for each,
		* passing it @data.
		*
		* We check the return of @fn each time. If it returns anything
		* other than 0, we break out and return that value.
		*
		* Note, we hold class->sem in this function, so it can not be
		* re-acquired in @fn, otherwise it will self-deadlocking. For
		* example, calls to add or remove class members would be verboten.
		*/
		int class_for_each_device(struct class class, void data,
		int (fn)(struct device , void *))
		{
		struct device *dev;
		int error = 0;

		if (!class)
		return -EINVAL;
		down(&class->sem);
		list_for_each_entry(dev, &class->devices, node) {
		dev = get_device(dev);
		if (dev) {
		error = fn(dev, data);
		put_device(dev);
		} else
		error = -ENODEV;
		if (error)
		break;
		}
		up(&class->sem);

		return error;
		}
		EXPORT_SYMBOL_GPL(class_for_each_device);

		/**
		* class_find_device - device iterator for locating a particular device
		* @class: the class we're iterating
		* @data: data for the match function
		* @match: function to check device
		*
		* This is similar to the class_for_each_dev() function above, but it
		* 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.

		* Note, you will need to drop the reference with put_device() after use.
		*
		* We hold class->sem in this function, so it can not be
		* re-acquired in @match, otherwise it will self-deadlocking. For
		* example, calls to add or remove class members would be verboten.
		*/
		struct device class_find_device(struct class class, void *data,
		int (match)(struct device , void *))
		{
		struct device *dev;
		int found = 0;

		if (!class)
		return NULL;

		down(&class->sem);
		list_for_each_entry(dev, &class->devices, node) {
		dev = get_device(dev);
		if (dev) {
		if (match(dev, data)) {
		found = 1;
		break;
		} else
		put_device(dev);
		} else
		break;
		}
		up(&class->sem);

		return found ? dev : NULL;
		}
		EXPORT_SYMBOL_GPL(class_find_device);

		/**
		* class_find_child - device iterator for locating a particular class_device
		* @class: the class we're iterating
		* @data: data for the match function
		* @match: function to check class_device
		*
		* This function returns a reference to a class_device that is 'found' for
		* later use, as determined by the @match callback.
		*
		* The callback should return 0 if the class_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 class_devices.
		*
		* Note, you will need to drop the reference with class_device_put() after use.
		*
		* We hold class->sem in this function, so it can not be
		* re-acquired in @match, otherwise it will self-deadlocking. For
		* example, calls to add or remove class members would be verboten.
		*/
		struct class_device class_find_child(struct class class, void *data,
		int (match)(struct class_device , void *))
		{
		struct class_device *dev;
		int found = 0;

		if (!class)
		return NULL;

		down(&class->sem);
		list_for_each_entry(dev, &class->children, node) {
		dev = class_device_get(dev);
		if (dev) {
		if (match(dev, data)) {
		found = 1;
		break;
		} else
		class_device_put(dev);
		} else
		break;
		}
		up(&class->sem);

		return found ? dev : NULL;
		}
		EXPORT_SYMBOL_GPL(class_find_child);

		int class_interface_register(struct class_interface *class_intf)
		{

include/linux/device.h

+7 −2

Original line number	Diff line number	Diff line
		@@ -177,8 +177,7 @@ struct class {
		struct list_head devices;
		struct list_head interfaces;
		struct kset class_dirs;
		struct semaphore sem; /* locks both the children and interfaces lists */

		struct semaphore sem; /* locks children, devices, interfaces */
		struct class_attribute * class_attrs;
		struct class_device_attribute * class_dev_attrs;
		struct device_attribute * dev_attrs;
		@@ -196,6 +195,12 @@ struct class {

		extern int __must_check class_register(struct class *);
		extern void class_unregister(struct class *);
		extern int class_for_each_device(struct class class, void data,
		int (fn)(struct device dev, void *data));
		extern struct device class_find_device(struct class class, void *data,
		int (match)(struct device , void *));
		extern struct class_device class_find_child(struct class class, void *data,
		int (match)(struct class_device , void *));


		struct class_attribute {