include/media/media-dev-allocator.h

   1 /* SPDX-License-Identifier: GPL-2.0+ */
   2 /*
   3  * media-dev-allocator.h - Media Controller Device Allocator API
   4  *
   5  * Copyright (c) 2019 Shuah Khan <shuah@kernel.org>
   6  *
   7  * Credits: Suggested by Laurent Pinchart <laurent.pinchart@ideasonboard.com>
   8  */
   9
  10 /*
  11  * This file adds a global ref-counted Media Controller Device Instance API.
  12  * A system wide global media device list is managed and each media device
  13  * includes a kref count. The last put on the media device releases the media
  14  * device instance.
  15  */
  16
  17 #ifndef _MEDIA_DEV_ALLOCATOR_H
  18 #define _MEDIA_DEV_ALLOCATOR_H
  19
  20 struct usb_device;
  21
  22 #if defined(CONFIG_MEDIA_CONTROLLER) && defined(CONFIG_USB)
  23 /**
  24  * media_device_usb_allocate() - Allocate and return struct &media device
  25  *
  26  * @udev:               struct &usb_device pointer
  27  * @module_name:        should be filled with %KBUILD_MODNAME
  28  * @owner:              struct module pointer %THIS_MODULE for the driver.
  29  *                      %THIS_MODULE is null for a built-in driver.
  30  *                      It is safe even when %THIS_MODULE is null.
  31  *
  32  * This interface should be called to allocate a Media Device when multiple
  33  * drivers share usb_device and the media device. This interface allocates
  34  * &media_device structure and calls media_device_usb_init() to initialize
  35  * it.
  36  *
  37  */
  38 struct media_device *media_device_usb_allocate(struct usb_device *udev,
  39                                                const char *module_name,
  40                                                struct module *owner);
  41 /**
  42  * media_device_delete() - Release media device. Calls kref_put().
  43  *
  44  * @mdev:               struct &media_device pointer
  45  * @module_name:        should be filled with %KBUILD_MODNAME
  46  * @owner:              struct module pointer %THIS_MODULE for the driver.
  47  *                      %THIS_MODULE is null for a built-in driver.
  48  *                      It is safe even when %THIS_MODULE is null.
  49  *
  50  * This interface should be called to put Media Device Instance kref.
  51  */
  52 void media_device_delete(struct media_device *mdev, const char *module_name,
  53                          struct module *owner);
  54 #else
  55 static inline struct media_device *media_device_usb_allocate(
  56                         struct usb_device *udev, const char *module_name,
  57                         struct module *owner)
  58                         { return NULL; }
  59 static inline void media_device_delete(
  60                         struct media_device *mdev, const char *module_name,
  61                         struct module *owner) { }
  62 #endif /* CONFIG_MEDIA_CONTROLLER && CONFIG_USB */
  63 #endif /* _MEDIA_DEV_ALLOCATOR_H */