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-rw-r--r--Documentation/video4linux/README.ivtv3
-rw-r--r--Documentation/video4linux/gspca.txt10
-rw-r--r--Documentation/video4linux/omap3isp.txt278
-rw-r--r--Documentation/video4linux/v4l2-framework.txt267
4 files changed, 518 insertions, 40 deletions
diff --git a/Documentation/video4linux/README.ivtv b/Documentation/video4linux/README.ivtv
index 42b06686eb78..2579b5b709ed 100644
--- a/Documentation/video4linux/README.ivtv
+++ b/Documentation/video4linux/README.ivtv
@@ -36,8 +36,7 @@ Additional features for the PVR-350 (CX23415 based):
* Provides comprehensive OSD (On Screen Display: ie. graphics overlaying the
video signal)
* Provides a framebuffer (allowing X applications to appear on the video
- device) (this framebuffer is not yet part of the kernel. In the meantime it
- is available from www.ivtvdriver.org).
+ device)
* Supports raw YUV output.
IMPORTANT: In case of problems first read this page:
diff --git a/Documentation/video4linux/gspca.txt b/Documentation/video4linux/gspca.txt
index 261776e0c5e1..5c542e60f51d 100644
--- a/Documentation/video4linux/gspca.txt
+++ b/Documentation/video4linux/gspca.txt
@@ -103,6 +103,7 @@ spca561 046d:092d Logitech QC Elch2
spca561 046d:092e Logitech QC Elch2
spca561 046d:092f Logitech QuickCam Express Plus
sunplus 046d:0960 Logitech ClickSmart 420
+nw80x 046d:d001 Logitech QuickCam Pro (dark focus ring)
sunplus 0471:0322 Philips DMVC1300K
zc3xx 0471:0325 Philips SPC 200 NC
zc3xx 0471:0326 Philips SPC 300 NC
@@ -150,10 +151,12 @@ sunplus 04fc:5330 Digitrex 2110
sunplus 04fc:5360 Sunplus Generic
spca500 04fc:7333 PalmPixDC85
sunplus 04fc:ffff Pure DigitalDakota
+nw80x 0502:d001 DVC V6
spca501 0506:00df 3Com HomeConnect Lite
sunplus 052b:1507 Megapixel 5 Pretec DC-1007
sunplus 052b:1513 Megapix V4
sunplus 052b:1803 MegaImage VI
+nw80x 052b:d001 EZCam Pro p35u
tv8532 0545:808b Veo Stingray
tv8532 0545:8333 Veo Stingray
sunplus 0546:3155 Polaroid PDC3070
@@ -177,6 +180,7 @@ sunplus 055f:c530 Mustek Gsmart LCD 3
sunplus 055f:c540 Gsmart D30
sunplus 055f:c630 Mustek MDC4000
sunplus 055f:c650 Mustek MDC5500Z
+nw80x 055f:d001 Mustek Wcam 300 mini
zc3xx 055f:d003 Mustek WCam300A
zc3xx 055f:d004 Mustek WCam300 AN
conex 0572:0041 Creative Notebook cx11646
@@ -195,14 +199,20 @@ gl860 05e3:0503 Genesys Logic PC Camera
gl860 05e3:f191 Genesys Logic PC Camera
spca561 060b:a001 Maxell Compact Pc PM3
zc3xx 0698:2003 CTX M730V built in
+nw80x 06a5:0000 Typhoon Webcam 100 USB
+nw80x 06a5:d001 Divio based webcams
+nw80x 06a5:d800 Divio Chicony TwinkleCam, Trust SpaceCam
spca500 06bd:0404 Agfa CL20
spca500 06be:0800 Optimedia
+nw80x 06be:d001 EZCam Pro p35u
sunplus 06d6:0031 Trust 610 LCD PowerC@m Zoom
spca506 06e1:a190 ADS Instant VCD
+ov534 06f8:3002 Hercules Blog Webcam
ov534_9 06f8:3003 Hercules Dualpix HD Weblog
sonixj 06f8:3004 Hercules Classic Silver
sonixj 06f8:3008 Hercules Deluxe Optical Glass
pac7302 06f8:3009 Hercules Classic Link
+nw80x 0728:d001 AVerMedia Camguard
spca508 0733:0110 ViewQuest VQ110
spca501 0733:0401 Intel Create and Share
spca501 0733:0402 ViewQuest M318B
diff --git a/Documentation/video4linux/omap3isp.txt b/Documentation/video4linux/omap3isp.txt
new file mode 100644
index 000000000000..69be2c782b98
--- /dev/null
+++ b/Documentation/video4linux/omap3isp.txt
@@ -0,0 +1,278 @@
+OMAP 3 Image Signal Processor (ISP) driver
+
+Copyright (C) 2010 Nokia Corporation
+Copyright (C) 2009 Texas Instruments, Inc.
+
+Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
+ Sakari Ailus <sakari.ailus@iki.fi>
+ David Cohen <dacohen@gmail.com>
+
+
+Introduction
+============
+
+This file documents the Texas Instruments OMAP 3 Image Signal Processor (ISP)
+driver located under drivers/media/video/omap3isp. The original driver was
+written by Texas Instruments but since that it has been rewritten (twice) at
+Nokia.
+
+The driver has been successfully used on the following versions of OMAP 3:
+
+ 3430
+ 3530
+ 3630
+
+The driver implements V4L2, Media controller and v4l2_subdev interfaces.
+Sensor, lens and flash drivers using the v4l2_subdev interface in the kernel
+are supported.
+
+
+Split to subdevs
+================
+
+The OMAP 3 ISP is split into V4L2 subdevs, each of the blocks inside the ISP
+having one subdev to represent it. Each of the subdevs provide a V4L2 subdev
+interface to userspace.
+
+ OMAP3 ISP CCP2
+ OMAP3 ISP CSI2a
+ OMAP3 ISP CCDC
+ OMAP3 ISP preview
+ OMAP3 ISP resizer
+ OMAP3 ISP AEWB
+ OMAP3 ISP AF
+ OMAP3 ISP histogram
+
+Each possible link in the ISP is modelled by a link in the Media controller
+interface. For an example program see [2].
+
+
+Controlling the OMAP 3 ISP
+==========================
+
+In general, the settings given to the OMAP 3 ISP take effect at the beginning
+of the following frame. This is done when the module becomes idle during the
+vertical blanking period on the sensor. In memory-to-memory operation the pipe
+is run one frame at a time. Applying the settings is done between the frames.
+
+All the blocks in the ISP, excluding the CSI-2 and possibly the CCP2 receiver,
+insist on receiving complete frames. Sensors must thus never send the ISP
+partial frames.
+
+Autoidle does have issues with some ISP blocks on the 3430, at least.
+Autoidle is only enabled on 3630 when the omap3isp module parameter autoidle
+is non-zero.
+
+
+Events
+======
+
+The OMAP 3 ISP driver does support the V4L2 event interface on CCDC and
+statistics (AEWB, AF and histogram) subdevs.
+
+The CCDC subdev produces V4L2_EVENT_OMAP3ISP_HS_VS type event on HS_VS
+interrupt which is used to signal frame start. The event is triggered exactly
+when the reception of the first line of the frame starts in the CCDC module.
+The event can be subscribed on the CCDC subdev.
+
+(When using parallel interface one must pay account to correct configuration
+of the VS signal polarity. This is automatically correct when using the serial
+receivers.)
+
+Each of the statistics subdevs is able to produce events. An event is
+generated whenever a statistics buffer can be dequeued by a user space
+application using the VIDIOC_OMAP3ISP_STAT_REQ IOCTL. The events available
+are:
+
+ V4L2_EVENT_OMAP3ISP_AEWB
+ V4L2_EVENT_OMAP3ISP_AF
+ V4L2_EVENT_OMAP3ISP_HIST
+
+The type of the event data is struct omap3isp_stat_event_status for these
+ioctls. If there is an error calculating the statistics, there will be an
+event as usual, but no related statistics buffer. In this case
+omap3isp_stat_event_status.buf_err is set to non-zero.
+
+
+Private IOCTLs
+==============
+
+The OMAP 3 ISP driver supports standard V4L2 IOCTLs and controls where
+possible and practical. Much of the functions provided by the ISP, however,
+does not fall under the standard IOCTLs --- gamma tables and configuration of
+statistics collection are examples of such.
+
+In general, there is a private ioctl for configuring each of the blocks
+containing hardware-dependent functions.
+
+The following private IOCTLs are supported:
+
+ VIDIOC_OMAP3ISP_CCDC_CFG
+ VIDIOC_OMAP3ISP_PRV_CFG
+ VIDIOC_OMAP3ISP_AEWB_CFG
+ VIDIOC_OMAP3ISP_HIST_CFG
+ VIDIOC_OMAP3ISP_AF_CFG
+ VIDIOC_OMAP3ISP_STAT_REQ
+ VIDIOC_OMAP3ISP_STAT_EN
+
+The parameter structures used by these ioctls are described in
+include/linux/omap3isp.h. The detailed functions of the ISP itself related to
+a given ISP block is described in the Technical Reference Manuals (TRMs) ---
+see the end of the document for those.
+
+While it is possible to use the ISP driver without any use of these private
+IOCTLs it is not possible to obtain optimal image quality this way. The AEWB,
+AF and histogram modules cannot be used without configuring them using the
+appropriate private IOCTLs.
+
+
+CCDC and preview block IOCTLs
+=============================
+
+The VIDIOC_OMAP3ISP_CCDC_CFG and VIDIOC_OMAP3ISP_PRV_CFG IOCTLs are used to
+configure, enable and disable functions in the CCDC and preview blocks,
+respectively. Both IOCTLs control several functions in the blocks they
+control. VIDIOC_OMAP3ISP_CCDC_CFG IOCTL accepts a pointer to struct
+omap3isp_ccdc_update_config as its argument. Similarly VIDIOC_OMAP3ISP_PRV_CFG
+accepts a pointer to struct omap3isp_prev_update_config. The definition of
+both structures is available in [1].
+
+The update field in the structures tells whether to update the configuration
+for the specific function and the flag tells whether to enable or disable the
+function.
+
+The update and flag bit masks accept the following values. Each separate
+functions in the CCDC and preview blocks is associated with a flag (either
+disable or enable; part of the flag field in the structure) and a pointer to
+configuration data for the function.
+
+Valid values for the update and flag fields are listed here for
+VIDIOC_OMAP3ISP_CCDC_CFG. Values may be or'ed to configure more than one
+function in the same IOCTL call.
+
+ OMAP3ISP_CCDC_ALAW
+ OMAP3ISP_CCDC_LPF
+ OMAP3ISP_CCDC_BLCLAMP
+ OMAP3ISP_CCDC_BCOMP
+ OMAP3ISP_CCDC_FPC
+ OMAP3ISP_CCDC_CULL
+ OMAP3ISP_CCDC_CONFIG_LSC
+ OMAP3ISP_CCDC_TBL_LSC
+
+The corresponding values for the VIDIOC_OMAP3ISP_PRV_CFG are here:
+
+ OMAP3ISP_PREV_LUMAENH
+ OMAP3ISP_PREV_INVALAW
+ OMAP3ISP_PREV_HRZ_MED
+ OMAP3ISP_PREV_CFA
+ OMAP3ISP_PREV_CHROMA_SUPP
+ OMAP3ISP_PREV_WB
+ OMAP3ISP_PREV_BLKADJ
+ OMAP3ISP_PREV_RGB2RGB
+ OMAP3ISP_PREV_COLOR_CONV
+ OMAP3ISP_PREV_YC_LIMIT
+ OMAP3ISP_PREV_DEFECT_COR
+ OMAP3ISP_PREV_GAMMABYPASS
+ OMAP3ISP_PREV_DRK_FRM_CAPTURE
+ OMAP3ISP_PREV_DRK_FRM_SUBTRACT
+ OMAP3ISP_PREV_LENS_SHADING
+ OMAP3ISP_PREV_NF
+ OMAP3ISP_PREV_GAMMA
+
+The associated configuration pointer for the function may not be NULL when
+enabling the function. When disabling a function the configuration pointer is
+ignored.
+
+
+Statistic blocks IOCTLs
+=======================
+
+The statistics subdevs do offer more dynamic configuration options than the
+other subdevs. They can be enabled, disable and reconfigured when the pipeline
+is in streaming state.
+
+The statistics blocks always get the input image data from the CCDC (as the
+histogram memory read isn't implemented). The statistics are dequeueable by
+the user from the statistics subdev nodes using private IOCTLs.
+
+The private IOCTLs offered by the AEWB, AF and histogram subdevs are heavily
+reflected by the register level interface offered by the ISP hardware. There
+are aspects that are purely related to the driver implementation and these are
+discussed next.
+
+VIDIOC_OMAP3ISP_STAT_EN
+-----------------------
+
+This private IOCTL enables/disables a statistic module. If this request is
+done before streaming, it will take effect as soon as the pipeline starts to
+stream. If the pipeline is already streaming, it will take effect as soon as
+the CCDC becomes idle.
+
+VIDIOC_OMAP3ISP_AEWB_CFG, VIDIOC_OMAP3ISP_HIST_CFG and VIDIOC_OMAP3ISP_AF_CFG
+-----------------------------------------------------------------------------
+
+Those IOCTLs are used to configure the modules. They require user applications
+to have an in-depth knowledge of the hardware. Most of the fields explanation
+can be found on OMAP's TRMs. The two following fields common to all the above
+configure private IOCTLs require explanation for better understanding as they
+are not part of the TRM.
+
+omap3isp_[h3a_af/h3a_aewb/hist]_config.buf_size:
+
+The modules handle their buffers internally. The necessary buffer size for the
+module's data output depends on the requested configuration. Although the
+driver supports reconfiguration while streaming, it does not support a
+reconfiguration which requires bigger buffer size than what is already
+internally allocated if the module is enabled. It will return -EBUSY on this
+case. In order to avoid such condition, either disable/reconfigure/enable the
+module or request the necessary buffer size during the first configuration
+while the module is disabled.
+
+The internal buffer size allocation considers the requested configuration's
+minimum buffer size and the value set on buf_size field. If buf_size field is
+out of [minimum, maximum] buffer size range, it's clamped to fit in there.
+The driver then selects the biggest value. The corrected buf_size value is
+written back to user application.
+
+omap3isp_[h3a_af/h3a_aewb/hist]_config.config_counter:
+
+As the configuration doesn't take effect synchronously to the request, the
+driver must provide a way to track this information to provide more accurate
+data. After a configuration is requested, the config_counter returned to user
+space application will be an unique value associated to that request. When
+user application receives an event for buffer availability or when a new
+buffer is requested, this config_counter is used to match a buffer data and a
+configuration.
+
+VIDIOC_OMAP3ISP_STAT_REQ
+------------------------
+
+Send to user space the oldest data available in the internal buffer queue and
+discards such buffer afterwards. The field omap3isp_stat_data.frame_number
+matches with the video buffer's field_count.
+
+
+Technical reference manuals (TRMs) and other documentation
+==========================================================
+
+OMAP 3430 TRM:
+<URL:http://focus.ti.com/pdfs/wtbu/OMAP34xx_ES3.1.x_PUBLIC_TRM_vZM.zip>
+Referenced 2011-03-05.
+
+OMAP 35xx TRM:
+<URL:http://www.ti.com/litv/pdf/spruf98o> Referenced 2011-03-05.
+
+OMAP 3630 TRM:
+<URL:http://focus.ti.com/pdfs/wtbu/OMAP36xx_ES1.x_PUBLIC_TRM_vQ.zip>
+Referenced 2011-03-05.
+
+DM 3730 TRM:
+<URL:http://www.ti.com/litv/pdf/sprugn4h> Referenced 2011-03-06.
+
+
+References
+==========
+
+[1] include/linux/omap3isp.h
+
+[2] http://git.ideasonboard.org/?p=media-ctl.git;a=summary
diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt
index f22f35c271f3..3b15608ee070 100644
--- a/Documentation/video4linux/v4l2-framework.txt
+++ b/Documentation/video4linux/v4l2-framework.txt
@@ -71,6 +71,10 @@ sub-device instances, the video_device struct stores V4L2 device node data
and in the future a v4l2_fh struct will keep track of filehandle instances
(this is not yet implemented).
+The V4L2 framework also optionally integrates with the media framework. If a
+driver sets the struct v4l2_device mdev field, sub-devices and video nodes
+will automatically appear in the media framework as entities.
+
struct v4l2_device
------------------
@@ -83,11 +87,20 @@ You must register the device instance:
v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev);
-Registration will initialize the v4l2_device struct and link dev->driver_data
-to v4l2_dev. If v4l2_dev->name is empty then it will be set to a value derived
-from dev (driver name followed by the bus_id, to be precise). If you set it
-up before calling v4l2_device_register then it will be untouched. If dev is
-NULL, then you *must* setup v4l2_dev->name before calling v4l2_device_register.
+Registration will initialize the v4l2_device struct. If the dev->driver_data
+field is NULL, it will be linked to v4l2_dev.
+
+Drivers that want integration with the media device framework need to set
+dev->driver_data manually to point to the driver-specific device structure
+that embed the struct v4l2_device instance. This is achieved by a
+dev_set_drvdata() call before registering the V4L2 device instance. They must
+also set the struct v4l2_device mdev field to point to a properly initialized
+and registered media_device instance.
+
+If v4l2_dev->name is empty then it will be set to a value derived from dev
+(driver name followed by the bus_id, to be precise). If you set it up before
+calling v4l2_device_register then it will be untouched. If dev is NULL, then
+you *must* setup v4l2_dev->name before calling v4l2_device_register.
You can use v4l2_device_set_name() to set the name based on a driver name and
a driver-global atomic_t instance. This will generate names like ivtv0, ivtv1,
@@ -108,6 +121,7 @@ You unregister with:
v4l2_device_unregister(struct v4l2_device *v4l2_dev);
+If the dev->driver_data field points to v4l2_dev, it will be reset to NULL.
Unregistering will also automatically unregister all subdevs from the device.
If you have a hotpluggable device (e.g. a USB device), then when a disconnect
@@ -167,6 +181,21 @@ static int __devinit drv_probe(struct pci_dev *pdev,
state->instance = atomic_inc_return(&drv_instance) - 1;
}
+If you have multiple device nodes then it can be difficult to know when it is
+safe to unregister v4l2_device. For this purpose v4l2_device has refcounting
+support. The refcount is increased whenever video_register_device is called and
+it is decreased whenever that device node is released. When the refcount reaches
+zero, then the v4l2_device release() callback is called. You can do your final
+cleanup there.
+
+If other device nodes (e.g. ALSA) are created, then you can increase and
+decrease the refcount manually as well by calling:
+
+void v4l2_device_get(struct v4l2_device *v4l2_dev);
+
+or:
+
+int v4l2_device_put(struct v4l2_device *v4l2_dev);
struct v4l2_subdev
------------------
@@ -254,6 +283,26 @@ A sub-device driver initializes the v4l2_subdev struct using:
Afterwards you need to initialize subdev->name with a unique name and set the
module owner. This is done for you if you use the i2c helper functions.
+If integration with the media framework is needed, you must initialize the
+media_entity struct embedded in the v4l2_subdev struct (entity field) by
+calling media_entity_init():
+
+ struct media_pad *pads = &my_sd->pads;
+ int err;
+
+ err = media_entity_init(&sd->entity, npads, pads, 0);
+
+The pads array must have been previously initialized. There is no need to
+manually set the struct media_entity type and name fields, but the revision
+field must be initialized if needed.
+
+A reference to the entity will be automatically acquired/released when the
+subdev device node (if any) is opened/closed.
+
+Don't forget to cleanup the media entity before the sub-device is destroyed:
+
+ media_entity_cleanup(&sd->entity);
+
A device (bridge) driver needs to register the v4l2_subdev with the
v4l2_device:
@@ -263,6 +312,9 @@ This can fail if the subdev module disappeared before it could be registered.
After this function was called successfully the subdev->dev field points to
the v4l2_device.
+If the v4l2_device parent device has a non-NULL mdev field, the sub-device
+entity will be automatically registered with the media device.
+
You can unregister a sub-device using:
v4l2_device_unregister_subdev(sd);
@@ -319,6 +371,61 @@ controlled through GPIO pins. This distinction is only relevant when setting
up the device, but once the subdev is registered it is completely transparent.
+V4L2 sub-device userspace API
+-----------------------------
+
+Beside exposing a kernel API through the v4l2_subdev_ops structure, V4L2
+sub-devices can also be controlled directly by userspace applications.
+
+Device nodes named v4l-subdevX can be created in /dev to access sub-devices
+directly. If a sub-device supports direct userspace configuration it must set
+the V4L2_SUBDEV_FL_HAS_DEVNODE flag before being registered.
+
+After registering sub-devices, the v4l2_device driver can create device nodes
+for all registered sub-devices marked with V4L2_SUBDEV_FL_HAS_DEVNODE by calling
+v4l2_device_register_subdev_nodes(). Those device nodes will be automatically
+removed when sub-devices are unregistered.
+
+The device node handles a subset of the V4L2 API.
+
+VIDIOC_QUERYCTRL
+VIDIOC_QUERYMENU
+VIDIOC_G_CTRL
+VIDIOC_S_CTRL
+VIDIOC_G_EXT_CTRLS
+VIDIOC_S_EXT_CTRLS
+VIDIOC_TRY_EXT_CTRLS
+
+ The controls ioctls are identical to the ones defined in V4L2. They
+ behave identically, with the only exception that they deal only with
+ controls implemented in the sub-device. Depending on the driver, those
+ controls can be also be accessed through one (or several) V4L2 device
+ nodes.
+
+VIDIOC_DQEVENT
+VIDIOC_SUBSCRIBE_EVENT
+VIDIOC_UNSUBSCRIBE_EVENT
+
+ The events ioctls are identical to the ones defined in V4L2. They
+ behave identically, with the only exception that they deal only with
+ events generated by the sub-device. Depending on the driver, those
+ events can also be reported by one (or several) V4L2 device nodes.
+
+ Sub-device drivers that want to use events need to set the
+ V4L2_SUBDEV_USES_EVENTS v4l2_subdev::flags and initialize
+ v4l2_subdev::nevents to events queue depth before registering the
+ sub-device. After registration events can be queued as usual on the
+ v4l2_subdev::devnode device node.
+
+ To properly support events, the poll() file operation is also
+ implemented.
+
+Private ioctls
+
+ All ioctls not in the above list are passed directly to the sub-device
+ driver through the core::ioctl operation.
+
+
I2C sub-device drivers
----------------------
@@ -457,6 +564,10 @@ You should also set these fields:
Otherwise you give it a pointer to a struct mutex_lock and before any
of the v4l2_file_operations is called this lock will be taken by the
core and released afterwards.
+- prio: keeps track of the priorities. Used to implement VIDIOC_G/S_PRIORITY.
+ If left to NULL, then it will use the struct v4l2_prio_state in v4l2_device.
+ If you want to have a separate priority state per (group of) device node(s),
+ then you can point it to your own struct v4l2_prio_state.
- parent: you only set this if v4l2_device was registered with NULL as
the parent device struct. This only happens in cases where one hardware
device has multiple PCI devices that all share the same v4l2_device core.
@@ -466,13 +577,34 @@ You should also set these fields:
(cx8802). Since the v4l2_device cannot be associated with a particular
PCI device it is setup without a parent device. But when the struct
video_device is setup you do know which parent PCI device to use.
+- flags: optional. Set to V4L2_FL_USE_FH_PRIO if you want to let the framework
+ handle the VIDIOC_G/S_PRIORITY ioctls. This requires that you use struct
+ v4l2_fh. Eventually this flag will disappear once all drivers use the core
+ priority handling. But for now it has to be set explicitly.
-If you use v4l2_ioctl_ops, then you should set either .unlocked_ioctl or
-.ioctl to video_ioctl2 in your v4l2_file_operations struct.
+If you use v4l2_ioctl_ops, then you should set .unlocked_ioctl to video_ioctl2
+in your v4l2_file_operations struct.
+
+Do not use .ioctl! This is deprecated and will go away in the future.
The v4l2_file_operations struct is a subset of file_operations. The main
difference is that the inode argument is omitted since it is never used.
+If integration with the media framework is needed, you must initialize the
+media_entity struct embedded in the video_device struct (entity field) by
+calling media_entity_init():
+
+ struct media_pad *pad = &my_vdev->pad;
+ int err;
+
+ err = media_entity_init(&vdev->entity, 1, pad, 0);
+
+The pads array must have been previously initialized. There is no need to
+manually set the struct media_entity type and name fields.
+
+A reference to the entity will be automatically acquired/released when the
+video device is opened/closed.
+
v4l2_file_operations and locking
--------------------------------
@@ -502,6 +634,9 @@ for you.
return err;
}
+If the v4l2_device parent device has a non-NULL mdev field, the video device
+entity will be automatically registered with the media device.
+
Which device is registered depends on the type argument. The following
types exist:
@@ -577,6 +712,13 @@ release, of course) will return an error as well.
When the last user of the video device node exits, then the vdev->release()
callback is called and you can do the final cleanup there.
+Don't forget to cleanup the media entity associated with the video device if
+it has been initialized:
+
+ media_entity_cleanup(&vdev->entity);
+
+This can be done from the release callback.
+
video_device helper functions
-----------------------------
@@ -636,39 +778,25 @@ struct v4l2_fh
--------------
struct v4l2_fh provides a way to easily keep file handle specific data
-that is used by the V4L2 framework. Using v4l2_fh is optional for
-drivers.
+that is used by the V4L2 framework. New drivers must use struct v4l2_fh
+since it is also used to implement priority handling (VIDIOC_G/S_PRIORITY)
+if the video_device flag V4L2_FL_USE_FH_PRIO is also set.
The users of v4l2_fh (in the V4L2 framework, not the driver) know
whether a driver uses v4l2_fh as its file->private_data pointer by
-testing the V4L2_FL_USES_V4L2_FH bit in video_device->flags.
-
-Useful functions:
-
-- v4l2_fh_init()
-
- Initialise the file handle. This *MUST* be performed in the driver's
- v4l2_file_operations->open() handler.
-
-- v4l2_fh_add()
+testing the V4L2_FL_USES_V4L2_FH bit in video_device->flags. This bit is
+set whenever v4l2_fh_init() is called.
- Add a v4l2_fh to video_device file handle list. May be called after
- initialising the file handle.
-
-- v4l2_fh_del()
-
- Unassociate the file handle from video_device(). The file handle
- exit function may now be called.
+struct v4l2_fh is allocated as a part of the driver's own file handle
+structure and file->private_data is set to it in the driver's open
+function by the driver.
-- v4l2_fh_exit()
+In many cases the struct v4l2_fh will be embedded in a larger structure.
+In that case you should call v4l2_fh_init+v4l2_fh_add in open() and
+v4l2_fh_del+v4l2_fh_exit in release().
- Uninitialise the file handle. After uninitialisation the v4l2_fh
- memory can be freed.
-
-struct v4l2_fh is allocated as a part of the driver's own file handle
-structure and is set to file->private_data in the driver's open
-function by the driver. Drivers can extract their own file handle
-structure by using the container_of macro. Example:
+Drivers can extract their own file handle structure by using the container_of
+macro. Example:
struct my_fh {
int blah;
@@ -685,15 +813,21 @@ int my_open(struct file *file)
...
+ my_fh = kzalloc(sizeof(*my_fh), GFP_KERNEL);
+
+ ...
+
ret = v4l2_fh_init(&my_fh->fh, vfd);
- if (ret)
+ if (ret) {
+ kfree(my_fh);
return ret;
+ }
- v4l2_fh_add(&my_fh->fh);
+ ...
file->private_data = &my_fh->fh;
-
- ...
+ v4l2_fh_add(&my_fh->fh);
+ return 0;
}
int my_release(struct file *file)
@@ -702,8 +836,65 @@ int my_release(struct file *file)
struct my_fh *my_fh = container_of(fh, struct my_fh, fh);
...
+ v4l2_fh_del(&my_fh->fh);
+ v4l2_fh_exit(&my_fh->fh);
+ kfree(my_fh);
+ return 0;
}
+Below is a short description of the v4l2_fh functions used:
+
+int v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev)
+
+ Initialise the file handle. This *MUST* be performed in the driver's
+ v4l2_file_operations->open() handler.
+
+void v4l2_fh_add(struct v4l2_fh *fh)
+
+ Add a v4l2_fh to video_device file handle list. Must be called once the
+ file handle is completely initialized.
+
+void v4l2_fh_del(struct v4l2_fh *fh)
+
+ Unassociate the file handle from video_device(). The file handle
+ exit function may now be called.
+
+void v4l2_fh_exit(struct v4l2_fh *fh)
+
+ Uninitialise the file handle. After uninitialisation the v4l2_fh
+ memory can be freed.
+
+
+If struct v4l2_fh is not embedded, then you can use these helper functions:
+
+int v4l2_fh_open(struct file *filp)
+
+ This allocates a struct v4l2_fh, initializes it and adds it to the struct
+ video_device associated with the file struct.
+
+int v4l2_fh_release(struct file *filp)
+
+ This deletes it from the struct video_device associated with the file
+ struct, uninitialised the v4l2_fh and frees it.
+
+These two functions can be plugged into the v4l2_file_operation's open() and
+release() ops.
+
+
+Several drivers need to do something when the first file handle is opened and
+when the last file handle closes. Two helper functions were added to check
+whether the v4l2_fh struct is the only open filehandle of the associated
+device node:
+
+int v4l2_fh_is_singular(struct v4l2_fh *fh)
+
+ Returns 1 if the file handle is the only open file handle, else 0.
+
+int v4l2_fh_is_singular_file(struct file *filp)
+
+ Same, but it calls v4l2_fh_is_singular with filp->private_data.
+
+
V4L2 events
-----------