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V4L/DVB (9820): v4l2: add v4l2_device and v4l2_subdev structs to the v4l2 framework.
Start implementing a proper v4l2 framework as discussed during the Linux Plumbers Conference 2008. Introduces v4l2_device (for device instances) and v4l2_subdev (representing sub-device instances). Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Reviewed-by: Laurent Pinchart <laurent.pinchart@skynet.be> Reviewed-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Reviewed-by: Andy Walls <awalls@radix.net> Reviewed-by: David Brownell <david-b@pacbell.net> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Hans Verkuil
Mauro Carvalho Chehab
parent
07b1747c8d
commit
2a1fcdf082
362
Documentation/video4linux/v4l2-framework.txt
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362
Documentation/video4linux/v4l2-framework.txt
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@ -0,0 +1,362 @@
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Overview of the V4L2 driver framework
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=====================================
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This text documents the various structures provided by the V4L2 framework and
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their relationships.
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Introduction
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------------
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The V4L2 drivers tend to be very complex due to the complexity of the
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hardware: most devices have multiple ICs, export multiple device nodes in
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/dev, and create also non-V4L2 devices such as DVB, ALSA, FB, I2C and input
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(IR) devices.
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Especially the fact that V4L2 drivers have to setup supporting ICs to
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do audio/video muxing/encoding/decoding makes it more complex than most.
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Usually these ICs are connected to the main bridge driver through one or
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more I2C busses, but other busses can also be used. Such devices are
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called 'sub-devices'.
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For a long time the framework was limited to the video_device struct for
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creating V4L device nodes and video_buf for handling the video buffers
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(note that this document does not discuss the video_buf framework).
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This meant that all drivers had to do the setup of device instances and
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connecting to sub-devices themselves. Some of this is quite complicated
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to do right and many drivers never did do it correctly.
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There is also a lot of common code that could never be refactored due to
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the lack of a framework.
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So this framework sets up the basic building blocks that all drivers
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need and this same framework should make it much easier to refactor
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common code into utility functions shared by all drivers.
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Structure of a driver
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---------------------
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All drivers have the following structure:
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1) A struct for each device instance containing the device state.
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2) A way of initializing and commanding sub-devices (if any).
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3) Creating V4L2 device nodes (/dev/videoX, /dev/vbiX, /dev/radioX and
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/dev/vtxX) and keeping track of device-node specific data.
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4) Filehandle-specific structs containing per-filehandle data.
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This is a rough schematic of how it all relates:
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device instances
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+-sub-device instances
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\-V4L2 device nodes
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\-filehandle instances
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Structure of the framework
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--------------------------
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The framework closely resembles the driver structure: it has a v4l2_device
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struct for the device instance data, a v4l2_subdev struct to refer to
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sub-device instances, the video_device struct stores V4L2 device node data
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and in the future a v4l2_fh struct will keep track of filehandle instances
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(this is not yet implemented).
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struct v4l2_device
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------------------
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Each device instance is represented by a struct v4l2_device (v4l2-device.h).
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Very simple devices can just allocate this struct, but most of the time you
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would embed this struct inside a larger struct.
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You must register the device instance:
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v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev);
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Registration will initialize the v4l2_device struct and link dev->driver_data
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to v4l2_dev. Registration will also set v4l2_dev->name to a value derived from
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dev (driver name followed by the bus_id, to be precise). You may change the
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name after registration if you want.
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You unregister with:
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v4l2_device_unregister(struct v4l2_device *v4l2_dev);
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Unregistering will also automatically unregister all subdevs from the device.
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Sometimes you need to iterate over all devices registered by a specific
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driver. This is usually the case if multiple device drivers use the same
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hardware. E.g. the ivtvfb driver is a framebuffer driver that uses the ivtv
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hardware. The same is true for alsa drivers for example.
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You can iterate over all registered devices as follows:
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static int callback(struct device *dev, void *p)
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{
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struct v4l2_device *v4l2_dev = dev_get_drvdata(dev);
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/* test if this device was inited */
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if (v4l2_dev == NULL)
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return 0;
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...
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return 0;
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}
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int iterate(void *p)
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{
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struct device_driver *drv;
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int err;
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/* Find driver 'ivtv' on the PCI bus.
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pci_bus_type is a global. For USB busses use usb_bus_type. */
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drv = driver_find("ivtv", &pci_bus_type);
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/* iterate over all ivtv device instances */
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err = driver_for_each_device(drv, NULL, p, callback);
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put_driver(drv);
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return err;
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}
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Sometimes you need to keep a running counter of the device instance. This is
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commonly used to map a device instance to an index of a module option array.
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The recommended approach is as follows:
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static atomic_t drv_instance = ATOMIC_INIT(0);
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static int __devinit drv_probe(struct pci_dev *dev,
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const struct pci_device_id *pci_id)
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{
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...
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state->instance = atomic_inc_return(&drv_instance) - 1;
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}
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struct v4l2_subdev
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------------------
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Many drivers need to communicate with sub-devices. These devices can do all
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sort of tasks, but most commonly they handle audio and/or video muxing,
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encoding or decoding. For webcams common sub-devices are sensors and camera
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controllers.
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Usually these are I2C devices, but not necessarily. In order to provide the
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driver with a consistent interface to these sub-devices the v4l2_subdev struct
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(v4l2-subdev.h) was created.
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Each sub-device driver must have a v4l2_subdev struct. This struct can be
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stand-alone for simple sub-devices or it might be embedded in a larger struct
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if more state information needs to be stored. Usually there is a low-level
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device struct (e.g. i2c_client) that contains the device data as setup
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by the kernel. It is recommended to store that pointer in the private
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data of v4l2_subdev using v4l2_set_subdevdata(). That makes it easy to go
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from a v4l2_subdev to the actual low-level bus-specific device data.
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You also need a way to go from the low-level struct to v4l2_subdev. For the
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common i2c_client struct the i2c_set_clientdata() call is used to store a
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v4l2_subdev pointer, for other busses you may have to use other methods.
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From the bridge driver perspective you load the sub-device module and somehow
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obtain the v4l2_subdev pointer. For i2c devices this is easy: you call
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i2c_get_clientdata(). For other busses something similar needs to be done.
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Helper functions exists for sub-devices on an I2C bus that do most of this
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tricky work for you.
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Each v4l2_subdev contains function pointers that sub-device drivers can
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implement (or leave NULL if it is not applicable). Since sub-devices can do
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so many different things and you do not want to end up with a huge ops struct
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of which only a handful of ops are commonly implemented, the function pointers
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are sorted according to category and each category has its own ops struct.
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The top-level ops struct contains pointers to the category ops structs, which
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may be NULL if the subdev driver does not support anything from that category.
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It looks like this:
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struct v4l2_subdev_core_ops {
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int (*g_chip_ident)(struct v4l2_subdev *sd, struct v4l2_chip_ident *chip);
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int (*log_status)(struct v4l2_subdev *sd);
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int (*init)(struct v4l2_subdev *sd, u32 val);
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...
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};
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struct v4l2_subdev_tuner_ops {
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...
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};
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struct v4l2_subdev_audio_ops {
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...
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};
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struct v4l2_subdev_video_ops {
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...
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};
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struct v4l2_subdev_ops {
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const struct v4l2_subdev_core_ops *core;
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const struct v4l2_subdev_tuner_ops *tuner;
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const struct v4l2_subdev_audio_ops *audio;
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const struct v4l2_subdev_video_ops *video;
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};
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The core ops are common to all subdevs, the other categories are implemented
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depending on the sub-device. E.g. a video device is unlikely to support the
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audio ops and vice versa.
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This setup limits the number of function pointers while still making it easy
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to add new ops and categories.
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A sub-device driver initializes the v4l2_subdev struct using:
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v4l2_subdev_init(subdev, &ops);
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Afterwards you need to initialize subdev->name with a unique name and set the
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module owner. This is done for you if you use the i2c helper functions.
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A device (bridge) driver needs to register the v4l2_subdev with the
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v4l2_device:
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int err = v4l2_device_register_subdev(device, subdev);
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This can fail if the subdev module disappeared before it could be registered.
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After this function was called successfully the subdev->dev field points to
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the v4l2_device.
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You can unregister a sub-device using:
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v4l2_device_unregister_subdev(subdev);
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Afterwards the subdev module can be unloaded and subdev->dev == NULL.
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You can call an ops function either directly:
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err = subdev->ops->core->g_chip_ident(subdev, &chip);
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but it is better and easier to use this macro:
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err = v4l2_subdev_call(subdev, core, g_chip_ident, &chip);
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The macro will to the right NULL pointer checks and returns -ENODEV if subdev
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is NULL, -ENOIOCTLCMD if either subdev->core or subdev->core->g_chip_ident is
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NULL, or the actual result of the subdev->ops->core->g_chip_ident ops.
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It is also possible to call all or a subset of the sub-devices:
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v4l2_device_call_all(dev, 0, core, g_chip_ident, &chip);
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Any subdev that does not support this ops is skipped and error results are
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ignored. If you want to check for errors use this:
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err = v4l2_device_call_until_err(dev, 0, core, g_chip_ident, &chip);
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Any error except -ENOIOCTLCMD will exit the loop with that error. If no
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errors (except -ENOIOCTLCMD) occured, then 0 is returned.
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The second argument to both calls is a group ID. If 0, then all subdevs are
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called. If non-zero, then only those whose group ID match that value will
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be called. Before a bridge driver registers a subdev it can set subdev->grp_id
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to whatever value it wants (it's 0 by default). This value is owned by the
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bridge driver and the sub-device driver will never modify or use it.
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The group ID gives the bridge driver more control how callbacks are called.
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For example, there may be multiple audio chips on a board, each capable of
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changing the volume. But usually only one will actually be used when the
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user want to change the volume. You can set the group ID for that subdev to
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e.g. AUDIO_CONTROLLER and specify that as the group ID value when calling
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v4l2_device_call_all(). That ensures that it will only go to the subdev
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that needs it.
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The advantage of using v4l2_subdev is that it is a generic struct and does
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not contain any knowledge about the underlying hardware. So a driver might
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contain several subdevs that use an I2C bus, but also a subdev that is
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controlled through GPIO pins. This distinction is only relevant when setting
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up the device, but once the subdev is registered it is completely transparent.
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I2C sub-device drivers
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----------------------
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Since these drivers are so common, special helper functions are available to
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ease the use of these drivers (v4l2-common.h).
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The recommended method of adding v4l2_subdev support to an I2C driver is to
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embed the v4l2_subdev struct into the state struct that is created for each
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I2C device instance. Very simple devices have no state struct and in that case
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you can just create a v4l2_subdev directly.
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A typical state struct would look like this (where 'chipname' is replaced by
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the name of the chip):
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struct chipname_state {
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struct v4l2_subdev sd;
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... /* additional state fields */
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};
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Initialize the v4l2_subdev struct as follows:
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v4l2_i2c_subdev_init(&state->sd, client, subdev_ops);
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This function will fill in all the fields of v4l2_subdev and ensure that the
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v4l2_subdev and i2c_client both point to one another.
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You should also add a helper inline function to go from a v4l2_subdev pointer
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to a chipname_state struct:
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static inline struct chipname_state *to_state(struct v4l2_subdev *sd)
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{
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return container_of(sd, struct chipname_state, sd);
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}
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Use this to go from the v4l2_subdev struct to the i2c_client struct:
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struct i2c_client *client = v4l2_get_subdevdata(sd);
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And this to go from an i2c_client to a v4l2_subdev struct:
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struct v4l2_subdev *sd = i2c_get_clientdata(client);
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Finally you need to make a command function to make driver->command()
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call the right subdev_ops functions:
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static int subdev_command(struct i2c_client *client, unsigned cmd, void *arg)
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{
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return v4l2_subdev_command(i2c_get_clientdata(client), cmd, arg);
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}
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If driver->command is never used then you can leave this out. Eventually the
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driver->command usage should be removed from v4l.
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Make sure to call v4l2_device_unregister_subdev(sd) when the remove() callback
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is called. This will unregister the sub-device from the bridge driver. It is
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safe to call this even if the sub-device was never registered.
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The bridge driver also has some helper functions it can use:
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struct v4l2_subdev *sd = v4l2_i2c_new_subdev(adapter, "module_foo", "chipid", 0x36);
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This loads the given module (can be NULL if no module needs to be loaded) and
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calls i2c_new_device() with the given i2c_adapter and chip/address arguments.
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If all goes well, then it registers the subdev with the v4l2_device. It gets
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the v4l2_device by calling i2c_get_adapdata(adapter), so you should make sure
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that adapdata is set to v4l2_device when you setup the i2c_adapter in your
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driver.
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You can also use v4l2_i2c_new_probed_subdev() which is very similar to
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v4l2_i2c_new_subdev(), except that it has an array of possible I2C addresses
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that it should probe. Internally it calls i2c_new_probed_device().
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Both functions return NULL if something went wrong.
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struct video_device
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-------------------
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Not yet documented.
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@ -10,7 +10,7 @@ stkwebcam-objs := stk-webcam.o stk-sensor.o
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omap2cam-objs := omap24xxcam.o omap24xxcam-dma.o
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videodev-objs := v4l2-dev.o v4l2-ioctl.o
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videodev-objs := v4l2-dev.o v4l2-ioctl.o v4l2-device.o v4l2-subdev.o
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obj-$(CONFIG_VIDEO_DEV) += videodev.o v4l2-compat-ioctl32.o v4l2-int-device.o
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86
drivers/media/video/v4l2-device.c
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86
drivers/media/video/v4l2-device.c
Normal file
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/*
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V4L2 device support.
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Copyright (C) 2008 Hans Verkuil <hverkuil@xs4all.nl>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
|
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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|
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You should have received a copy of the GNU General Public License
|
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along with this program; if not, write to the Free Software
|
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/types.h>
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#include <linux/ioctl.h>
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#include <linux/i2c.h>
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#include <linux/videodev2.h>
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#include <media/v4l2-device.h>
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int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev)
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{
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if (dev == NULL || v4l2_dev == NULL)
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return -EINVAL;
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/* Warn if we apparently re-register a device */
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WARN_ON(dev_get_drvdata(dev));
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INIT_LIST_HEAD(&v4l2_dev->subdevs);
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spin_lock_init(&v4l2_dev->lock);
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v4l2_dev->dev = dev;
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snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s",
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dev->driver->name, dev->bus_id);
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dev_set_drvdata(dev, v4l2_dev);
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return 0;
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}
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EXPORT_SYMBOL_GPL(v4l2_device_register);
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void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
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{
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struct v4l2_subdev *sd, *next;
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if (v4l2_dev == NULL || v4l2_dev->dev == NULL)
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return;
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dev_set_drvdata(v4l2_dev->dev, NULL);
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/* unregister subdevs */
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list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list)
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v4l2_device_unregister_subdev(sd);
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v4l2_dev->dev = NULL;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(v4l2_device_unregister);
|
||||
|
||||
int v4l2_device_register_subdev(struct v4l2_device *dev, struct v4l2_subdev *sd)
|
||||
{
|
||||
/* Check for valid input */
|
||||
if (dev == NULL || sd == NULL || !sd->name[0])
|
||||
return -EINVAL;
|
||||
/* Warn if we apparently re-register a subdev */
|
||||
WARN_ON(sd->dev);
|
||||
if (!try_module_get(sd->owner))
|
||||
return -ENODEV;
|
||||
sd->dev = dev;
|
||||
spin_lock(&dev->lock);
|
||||
list_add_tail(&sd->list, &dev->subdevs);
|
||||
spin_unlock(&dev->lock);
|
||||
return 0;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
|
||||
|
||||
void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
|
||||
{
|
||||
/* return if it isn't registered */
|
||||
if (sd == NULL || sd->dev == NULL)
|
||||
return;
|
||||
spin_lock(&sd->dev->lock);
|
||||
list_del(&sd->list);
|
||||
spin_unlock(&sd->dev->lock);
|
||||
sd->dev = NULL;
|
||||
module_put(sd->owner);
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);
|
||||
108
drivers/media/video/v4l2-subdev.c
Normal file
108
drivers/media/video/v4l2-subdev.c
Normal file
@ -0,0 +1,108 @@
|
||||
/*
|
||||
V4L2 sub-device support.
|
||||
|
||||
Copyright (C) 2008 Hans Verkuil <hverkuil@xs4all.nl>
|
||||
|
||||
This program is free software; you can redistribute it and/or modify
|
||||
it under the terms of the GNU General Public License as published by
|
||||
the Free Software Foundation; either version 2 of the License, or
|
||||
(at your option) any later version.
|
||||
|
||||
This program is distributed in the hope that it will be useful,
|
||||
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
GNU General Public License for more details.
|
||||
|
||||
You should have received a copy of the GNU General Public License
|
||||
along with this program; if not, write to the Free Software
|
||||
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
||||
*/
|
||||
|
||||
#include <linux/types.h>
|
||||
#include <linux/ioctl.h>
|
||||
#include <linux/i2c.h>
|
||||
#include <linux/videodev2.h>
|
||||
#include <media/v4l2-subdev.h>
|
||||
|
||||
int v4l2_subdev_command(struct v4l2_subdev *sd, unsigned cmd, void *arg)
|
||||
{
|
||||
switch (cmd) {
|
||||
case VIDIOC_QUERYCTRL:
|
||||
return v4l2_subdev_call(sd, core, querymenu, arg);
|
||||
case VIDIOC_G_CTRL:
|
||||
return v4l2_subdev_call(sd, core, g_ctrl, arg);
|
||||
case VIDIOC_S_CTRL:
|
||||
return v4l2_subdev_call(sd, core, s_ctrl, arg);
|
||||
case VIDIOC_QUERYMENU:
|
||||
return v4l2_subdev_call(sd, core, queryctrl, arg);
|
||||
case VIDIOC_LOG_STATUS:
|
||||
return v4l2_subdev_call(sd, core, log_status);
|
||||
case VIDIOC_G_CHIP_IDENT:
|
||||
return v4l2_subdev_call(sd, core, g_chip_ident, arg);
|
||||
case VIDIOC_INT_S_STANDBY:
|
||||
return v4l2_subdev_call(sd, core, s_standby, *(u32 *)arg);
|
||||
case VIDIOC_INT_RESET:
|
||||
return v4l2_subdev_call(sd, core, reset, *(u32 *)arg);
|
||||
case VIDIOC_INT_S_GPIO:
|
||||
return v4l2_subdev_call(sd, core, s_gpio, *(u32 *)arg);
|
||||
case VIDIOC_INT_INIT:
|
||||
return v4l2_subdev_call(sd, core, init, *(u32 *)arg);
|
||||
#ifdef CONFIG_VIDEO_ADV_DEBUG
|
||||
case VIDIOC_DBG_G_REGISTER:
|
||||
return v4l2_subdev_call(sd, core, g_register, arg);
|
||||
case VIDIOC_DBG_S_REGISTER:
|
||||
return v4l2_subdev_call(sd, core, s_register, arg);
|
||||
#endif
|
||||
|
||||
case VIDIOC_INT_S_TUNER_MODE:
|
||||
return v4l2_subdev_call(sd, tuner, s_mode, *(enum v4l2_tuner_type *)arg);
|
||||
case AUDC_SET_RADIO:
|
||||
return v4l2_subdev_call(sd, tuner, s_radio);
|
||||
case VIDIOC_S_TUNER:
|
||||
return v4l2_subdev_call(sd, tuner, s_tuner, arg);
|
||||
case VIDIOC_G_TUNER:
|
||||
return v4l2_subdev_call(sd, tuner, g_tuner, arg);
|
||||
case VIDIOC_S_STD:
|
||||
return v4l2_subdev_call(sd, tuner, s_std, *(v4l2_std_id *)arg);
|
||||
case VIDIOC_S_FREQUENCY:
|
||||
return v4l2_subdev_call(sd, tuner, s_frequency, arg);
|
||||
case VIDIOC_G_FREQUENCY:
|
||||
return v4l2_subdev_call(sd, tuner, g_frequency, arg);
|
||||
case TUNER_SET_TYPE_ADDR:
|
||||
return v4l2_subdev_call(sd, tuner, s_type_addr, arg);
|
||||
case TUNER_SET_CONFIG:
|
||||
return v4l2_subdev_call(sd, tuner, s_config, arg);
|
||||
|
||||
case VIDIOC_INT_AUDIO_CLOCK_FREQ:
|
||||
return v4l2_subdev_call(sd, audio, s_clock_freq, *(u32 *)arg);
|
||||
case VIDIOC_INT_S_AUDIO_ROUTING:
|
||||
return v4l2_subdev_call(sd, audio, s_routing, arg);
|
||||
case VIDIOC_INT_I2S_CLOCK_FREQ:
|
||||
return v4l2_subdev_call(sd, audio, s_i2s_clock_freq, *(u32 *)arg);
|
||||
|
||||
case VIDIOC_INT_S_VIDEO_ROUTING:
|
||||
return v4l2_subdev_call(sd, video, s_routing, arg);
|
||||
case VIDIOC_INT_S_CRYSTAL_FREQ:
|
||||
return v4l2_subdev_call(sd, video, s_crystal_freq, arg);
|
||||
case VIDIOC_INT_DECODE_VBI_LINE:
|
||||
return v4l2_subdev_call(sd, video, decode_vbi_line, arg);
|
||||
case VIDIOC_INT_S_VBI_DATA:
|
||||
return v4l2_subdev_call(sd, video, s_vbi_data, arg);
|
||||
case VIDIOC_INT_G_VBI_DATA:
|
||||
return v4l2_subdev_call(sd, video, g_vbi_data, arg);
|
||||
case VIDIOC_S_FMT:
|
||||
return v4l2_subdev_call(sd, video, s_fmt, arg);
|
||||
case VIDIOC_G_FMT:
|
||||
return v4l2_subdev_call(sd, video, g_fmt, arg);
|
||||
case VIDIOC_INT_S_STD_OUTPUT:
|
||||
return v4l2_subdev_call(sd, video, s_std_output, *(v4l2_std_id *)arg);
|
||||
case VIDIOC_STREAMON:
|
||||
return v4l2_subdev_call(sd, video, s_stream, 1);
|
||||
case VIDIOC_STREAMOFF:
|
||||
return v4l2_subdev_call(sd, video, s_stream, 0);
|
||||
|
||||
default:
|
||||
return v4l2_subdev_call(sd, core, ioctl, cmd, arg);
|
||||
}
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(v4l2_subdev_command);
|
||||
109
include/media/v4l2-device.h
Normal file
109
include/media/v4l2-device.h
Normal file
@ -0,0 +1,109 @@
|
||||
/*
|
||||
V4L2 device support header.
|
||||
|
||||
Copyright (C) 2008 Hans Verkuil <hverkuil@xs4all.nl>
|
||||
|
||||
This program is free software; you can redistribute it and/or modify
|
||||
it under the terms of the GNU General Public License as published by
|
||||
the Free Software Foundation; either version 2 of the License, or
|
||||
(at your option) any later version.
|
||||
|
||||
This program is distributed in the hope that it will be useful,
|
||||
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
GNU General Public License for more details.
|
||||
|
||||
You should have received a copy of the GNU General Public License
|
||||
along with this program; if not, write to the Free Software
|
||||
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
||||
*/
|
||||
|
||||
#ifndef _V4L2_DEVICE_H
|
||||
#define _V4L2_DEVICE_H
|
||||
|
||||
#include <media/v4l2-subdev.h>
|
||||
|
||||
/* Each instance of a V4L2 device should create the v4l2_device struct,
|
||||
either stand-alone or embedded in a larger struct.
|
||||
|
||||
It allows easy access to sub-devices (see v4l2-subdev.h) and provides
|
||||
basic V4L2 device-level support.
|
||||
*/
|
||||
|
||||
#define V4L2_DEVICE_NAME_SIZE (BUS_ID_SIZE + 16)
|
||||
|
||||
struct v4l2_device {
|
||||
/* dev->driver_data points to this struct */
|
||||
struct device *dev;
|
||||
/* used to keep track of the registered subdevs */
|
||||
struct list_head subdevs;
|
||||
/* lock this struct; can be used by the driver as well if this
|
||||
struct is embedded into a larger struct. */
|
||||
spinlock_t lock;
|
||||
/* unique device name, by default the driver name + bus ID */
|
||||
char name[V4L2_DEVICE_NAME_SIZE];
|
||||
};
|
||||
|
||||
/* Initialize v4l2_dev and make dev->driver_data point to v4l2_dev */
|
||||
int __must_check v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev);
|
||||
/* Set v4l2_dev->dev->driver_data to NULL and unregister all sub-devices */
|
||||
void v4l2_device_unregister(struct v4l2_device *v4l2_dev);
|
||||
|
||||
/* Register a subdev with a v4l2 device. While registered the subdev module
|
||||
is marked as in-use. An error is returned if the module is no longer
|
||||
loaded when you attempt to register it. */
|
||||
int __must_check v4l2_device_register_subdev(struct v4l2_device *dev, struct v4l2_subdev *sd);
|
||||
/* Unregister a subdev with a v4l2 device. Can also be called if the subdev
|
||||
wasn't registered. In that case it will do nothing. */
|
||||
void v4l2_device_unregister_subdev(struct v4l2_subdev *sd);
|
||||
|
||||
/* Iterate over all subdevs. */
|
||||
#define v4l2_device_for_each_subdev(sd, dev) \
|
||||
list_for_each_entry(sd, &(dev)->subdevs, list)
|
||||
|
||||
/* Call the specified callback for all subdevs matching the condition.
|
||||
Ignore any errors. Note that you cannot add or delete a subdev
|
||||
while walking the subdevs list. */
|
||||
#define __v4l2_device_call_subdevs(dev, cond, o, f, args...) \
|
||||
do { \
|
||||
struct v4l2_subdev *sd; \
|
||||
\
|
||||
list_for_each_entry(sd, &(dev)->subdevs, list) \
|
||||
if ((cond) && sd->ops->o && sd->ops->o->f) \
|
||||
sd->ops->o->f(sd , ##args); \
|
||||
} while (0)
|
||||
|
||||
/* Call the specified callback for all subdevs matching the condition.
|
||||
If the callback returns an error other than 0 or -ENOIOCTLCMD, then
|
||||
return with that error code. Note that you cannot add or delete a
|
||||
subdev while walking the subdevs list. */
|
||||
#define __v4l2_device_call_subdevs_until_err(dev, cond, o, f, args...) \
|
||||
({ \
|
||||
struct v4l2_subdev *sd; \
|
||||
int err = 0; \
|
||||
\
|
||||
list_for_each_entry(sd, &(dev)->subdevs, list) { \
|
||||
if ((cond) && sd->ops->o && sd->ops->o->f) \
|
||||
err = sd->ops->o->f(sd , ##args); \
|
||||
if (err && err != -ENOIOCTLCMD) \
|
||||
break; \
|
||||
} \
|
||||
(err == -ENOIOCTLCMD) ? 0 : err; \
|
||||
})
|
||||
|
||||
/* Call the specified callback for all subdevs matching grp_id (if 0, then
|
||||
match them all). Ignore any errors. Note that you cannot add or delete
|
||||
a subdev while walking the subdevs list. */
|
||||
#define v4l2_device_call_all(dev, grp_id, o, f, args...) \
|
||||
__v4l2_device_call_subdevs(dev, \
|
||||
!(grp_id) || sd->grp_id == (grp_id), o, f , ##args)
|
||||
|
||||
/* Call the specified callback for all subdevs matching grp_id (if 0, then
|
||||
match them all). If the callback returns an error other than 0 or
|
||||
-ENOIOCTLCMD, then return with that error code. Note that you cannot
|
||||
add or delete a subdev while walking the subdevs list. */
|
||||
#define v4l2_device_call_until_err(dev, grp_id, o, f, args...) \
|
||||
__v4l2_device_call_subdevs_until_err(dev, \
|
||||
!(grp_id) || sd->grp_id == (grp_id), o, f , ##args)
|
||||
|
||||
#endif
|
||||
188
include/media/v4l2-subdev.h
Normal file
188
include/media/v4l2-subdev.h
Normal file
@ -0,0 +1,188 @@
|
||||
/*
|
||||
V4L2 sub-device support header.
|
||||
|
||||
Copyright (C) 2008 Hans Verkuil <hverkuil@xs4all.nl>
|
||||
|
||||
This program is free software; you can redistribute it and/or modify
|
||||
it under the terms of the GNU General Public License as published by
|
||||
the Free Software Foundation; either version 2 of the License, or
|
||||
(at your option) any later version.
|
||||
|
||||
This program is distributed in the hope that it will be useful,
|
||||
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
GNU General Public License for more details.
|
||||
|
||||
You should have received a copy of the GNU General Public License
|
||||
along with this program; if not, write to the Free Software
|
||||
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
||||
*/
|
||||
|
||||
#ifndef _V4L2_SUBDEV_H
|
||||
#define _V4L2_SUBDEV_H
|
||||
|
||||
#include <media/v4l2-common.h>
|
||||
|
||||
struct v4l2_device;
|
||||
struct v4l2_subdev;
|
||||
struct tuner_setup;
|
||||
|
||||
/* Sub-devices are devices that are connected somehow to the main bridge
|
||||
device. These devices are usually audio/video muxers/encoders/decoders or
|
||||
sensors and webcam controllers.
|
||||
|
||||
Usually these devices are controlled through an i2c bus, but other busses
|
||||
may also be used.
|
||||
|
||||
The v4l2_subdev struct provides a way of accessing these devices in a
|
||||
generic manner. Most operations that these sub-devices support fall in
|
||||
a few categories: core ops, audio ops, video ops and tuner ops.
|
||||
|
||||
More categories can be added if needed, although this should remain a
|
||||
limited set (no more than approx. 8 categories).
|
||||
|
||||
Each category has its own set of ops that subdev drivers can implement.
|
||||
|
||||
A subdev driver can leave the pointer to the category ops NULL if
|
||||
it does not implement them (e.g. an audio subdev will generally not
|
||||
implement the video category ops). The exception is the core category:
|
||||
this must always be present.
|
||||
|
||||
These ops are all used internally so it is no problem to change, remove
|
||||
or add ops or move ops from one to another category. Currently these
|
||||
ops are based on the original ioctls, but since ops are not limited to
|
||||
one argument there is room for improvement here once all i2c subdev
|
||||
drivers are converted to use these ops.
|
||||
*/
|
||||
|
||||
/* Core ops: it is highly recommended to implement at least these ops:
|
||||
|
||||
g_chip_ident
|
||||
log_status
|
||||
g_register
|
||||
s_register
|
||||
|
||||
This provides basic debugging support.
|
||||
|
||||
The ioctl ops is meant for generic ioctl-like commands. Depending on
|
||||
the use-case it might be better to use subdev-specific ops (currently
|
||||
not yet implemented) since ops provide proper type-checking.
|
||||
*/
|
||||
struct v4l2_subdev_core_ops {
|
||||
int (*g_chip_ident)(struct v4l2_subdev *sd, struct v4l2_chip_ident *chip);
|
||||
int (*log_status)(struct v4l2_subdev *sd);
|
||||
int (*init)(struct v4l2_subdev *sd, u32 val);
|
||||
int (*s_standby)(struct v4l2_subdev *sd, u32 standby);
|
||||
int (*reset)(struct v4l2_subdev *sd, u32 val);
|
||||
int (*s_gpio)(struct v4l2_subdev *sd, u32 val);
|
||||
int (*queryctrl)(struct v4l2_subdev *sd, struct v4l2_queryctrl *qc);
|
||||
int (*g_ctrl)(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
|
||||
int (*s_ctrl)(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
|
||||
int (*querymenu)(struct v4l2_subdev *sd, struct v4l2_querymenu *qm);
|
||||
int (*ioctl)(struct v4l2_subdev *sd, int cmd, void *arg);
|
||||
#ifdef CONFIG_VIDEO_ADV_DEBUG
|
||||
int (*g_register)(struct v4l2_subdev *sd, struct v4l2_register *reg);
|
||||
int (*s_register)(struct v4l2_subdev *sd, struct v4l2_register *reg);
|
||||
#endif
|
||||
};
|
||||
|
||||
struct v4l2_subdev_tuner_ops {
|
||||
int (*s_mode)(struct v4l2_subdev *sd, enum v4l2_tuner_type);
|
||||
int (*s_radio)(struct v4l2_subdev *sd);
|
||||
int (*s_frequency)(struct v4l2_subdev *sd, struct v4l2_frequency *freq);
|
||||
int (*g_frequency)(struct v4l2_subdev *sd, struct v4l2_frequency *freq);
|
||||
int (*g_tuner)(struct v4l2_subdev *sd, struct v4l2_tuner *vt);
|
||||
int (*s_tuner)(struct v4l2_subdev *sd, struct v4l2_tuner *vt);
|
||||
int (*s_std)(struct v4l2_subdev *sd, v4l2_std_id norm);
|
||||
int (*s_type_addr)(struct v4l2_subdev *sd, struct tuner_setup *type);
|
||||
int (*s_config)(struct v4l2_subdev *sd, const struct v4l2_priv_tun_config *config);
|
||||
};
|
||||
|
||||
struct v4l2_subdev_audio_ops {
|
||||
int (*s_clock_freq)(struct v4l2_subdev *sd, u32 freq);
|
||||
int (*s_i2s_clock_freq)(struct v4l2_subdev *sd, u32 freq);
|
||||
int (*s_routing)(struct v4l2_subdev *sd, const struct v4l2_routing *route);
|
||||
};
|
||||
|
||||
struct v4l2_subdev_video_ops {
|
||||
int (*s_routing)(struct v4l2_subdev *sd, const struct v4l2_routing *route);
|
||||
int (*s_crystal_freq)(struct v4l2_subdev *sd, struct v4l2_crystal_freq *freq);
|
||||
int (*decode_vbi_line)(struct v4l2_subdev *sd, struct v4l2_decode_vbi_line *vbi_line);
|
||||
int (*s_vbi_data)(struct v4l2_subdev *sd, const struct v4l2_sliced_vbi_data *vbi_data);
|
||||
int (*g_vbi_data)(struct v4l2_subdev *sd, struct v4l2_sliced_vbi_data *vbi_data);
|
||||
int (*s_std_output)(struct v4l2_subdev *sd, v4l2_std_id std);
|
||||
int (*s_stream)(struct v4l2_subdev *sd, int enable);
|
||||
int (*s_fmt)(struct v4l2_subdev *sd, struct v4l2_format *fmt);
|
||||
int (*g_fmt)(struct v4l2_subdev *sd, struct v4l2_format *fmt);
|
||||
};
|
||||
|
||||
struct v4l2_subdev_ops {
|
||||
const struct v4l2_subdev_core_ops *core;
|
||||
const struct v4l2_subdev_tuner_ops *tuner;
|
||||
const struct v4l2_subdev_audio_ops *audio;
|
||||
const struct v4l2_subdev_video_ops *video;
|
||||
};
|
||||
|
||||
#define V4L2_SUBDEV_NAME_SIZE 32
|
||||
|
||||
/* Each instance of a subdev driver should create this struct, either
|
||||
stand-alone or embedded in a larger struct.
|
||||
*/
|
||||
struct v4l2_subdev {
|
||||
struct list_head list;
|
||||
struct module *owner;
|
||||
struct v4l2_device *dev;
|
||||
const struct v4l2_subdev_ops *ops;
|
||||
/* name must be unique */
|
||||
char name[V4L2_SUBDEV_NAME_SIZE];
|
||||
/* can be used to group similar subdevs, value is driver-specific */
|
||||
u32 grp_id;
|
||||
/* pointer to private data */
|
||||
void *priv;
|
||||
};
|
||||
|
||||
static inline void v4l2_set_subdevdata(struct v4l2_subdev *sd, void *p)
|
||||
{
|
||||
sd->priv = p;
|
||||
}
|
||||
|
||||
static inline void *v4l2_get_subdevdata(const struct v4l2_subdev *sd)
|
||||
{
|
||||
return sd->priv;
|
||||
}
|
||||
|
||||
/* Convert an ioctl-type command to the proper v4l2_subdev_ops function call.
|
||||
This is used by subdev modules that can be called by both old-style ioctl
|
||||
commands and through the v4l2_subdev_ops.
|
||||
|
||||
The ioctl API of the subdev driver can call this function to call the
|
||||
right ops based on the ioctl cmd and arg.
|
||||
|
||||
Once all subdev drivers have been converted and all drivers no longer
|
||||
use the ioctl interface, then this function can be removed.
|
||||
*/
|
||||
int v4l2_subdev_command(struct v4l2_subdev *sd, unsigned cmd, void *arg);
|
||||
|
||||
static inline void v4l2_subdev_init(struct v4l2_subdev *sd,
|
||||
const struct v4l2_subdev_ops *ops)
|
||||
{
|
||||
INIT_LIST_HEAD(&sd->list);
|
||||
/* ops->core MUST be set */
|
||||
BUG_ON(!ops || !ops->core);
|
||||
sd->ops = ops;
|
||||
sd->dev = NULL;
|
||||
sd->name[0] = '\0';
|
||||
sd->grp_id = 0;
|
||||
sd->priv = NULL;
|
||||
}
|
||||
|
||||
/* Call an ops of a v4l2_subdev, doing the right checks against
|
||||
NULL pointers.
|
||||
|
||||
Example: err = v4l2_subdev_call(sd, core, g_chip_ident, &chip);
|
||||
*/
|
||||
#define v4l2_subdev_call(sd, o, f, args...) \
|
||||
(!(sd) ? -ENODEV : (((sd) && (sd)->ops->o && (sd)->ops->o->f) ? \
|
||||
(sd)->ops->o->f((sd) , ##args) : -ENOIOCTLCMD))
|
||||
|
||||
#endif
|
||||
Loading…
Reference in New Issue
Block a user