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- VPBE V4L2 driver design
- ======================================================================
- File partitioning
- -----------------
- V4L2 display device driver
- drivers/media/platform/davinci/vpbe_display.c
- drivers/media/platform/davinci/vpbe_display.h
- VPBE display controller
- drivers/media/platform/davinci/vpbe.c
- drivers/media/platform/davinci/vpbe.h
- VPBE venc sub device driver
- drivers/media/platform/davinci/vpbe_venc.c
- drivers/media/platform/davinci/vpbe_venc.h
- drivers/media/platform/davinci/vpbe_venc_regs.h
- VPBE osd driver
- drivers/media/platform/davinci/vpbe_osd.c
- drivers/media/platform/davinci/vpbe_osd.h
- drivers/media/platform/davinci/vpbe_osd_regs.h
- Functional partitioning
- -----------------------
- Consists of the following (in the same order as the list under file
- partitioning):-
- 1. V4L2 display driver
- Implements creation of video2 and video3 device nodes and
- provides v4l2 device interface to manage VID0 and VID1 layers.
- 2. Display controller
- Loads up VENC, OSD and external encoders such as ths8200. It provides
- a set of API calls to V4L2 drivers to set the output/standards
- in the VENC or external sub devices. It also provides
- a device object to access the services from OSD subdevice
- using sub device ops. The connection of external encoders to VENC LCD
- controller port is done at init time based on default output and standard
- selection or at run time when application change the output through
- V4L2 IOCTLs.
- When connected to an external encoder, vpbe controller is also responsible
- for setting up the interface between VENC and external encoders based on
- board specific settings (specified in board-xxx-evm.c). This allows
- interfacing external encoders such as ths8200. The setup_if_config()
- is implemented for this as well as configure_venc() (part of the next patch)
- API to set timings in VENC for a specific display resolution. As of this
- patch series, the interconnection and enabling and setting of the external
- encoders is not present, and would be a part of the next patch series.
- 3. VENC subdevice module
- Responsible for setting outputs provided through internal DACs and also
- setting timings at LCD controller port when external encoders are connected
- at the port or LCD panel timings required. When external encoder/LCD panel
- is connected, the timings for a specific standard/preset is retrieved from
- the board specific table and the values are used to set the timings in
- venc using non-standard timing mode.
- Support LCD Panel displays using the VENC. For example to support a Logic
- PD display, it requires setting up the LCD controller port with a set of
- timings for the resolution supported and setting the dot clock. So we could
- add the available outputs as a board specific entry (i.e add the "LogicPD"
- output name to board-xxx-evm.c). A table of timings for various LCDs
- supported can be maintained in the board specific setup file to support
- various LCD displays.As of this patch a basic driver is present, and this
- support for external encoders and displays forms a part of the next
- patch series.
- 4. OSD module
- OSD module implements all OSD layer management and hardware specific
- features. The VPBE module interacts with the OSD for enabling and
- disabling appropriate features of the OSD.
- Current status:-
- A fully functional working version of the V4L2 driver is available. This
- driver has been tested with NTSC and PAL standards and buffer streaming.
- Following are TBDs.
- vpbe display controller
- - Add support for external encoders.
- - add support for selecting external encoder as default at probe time.
- vpbe venc sub device
- - add timings for supporting ths8200
- - add support for LogicPD LCD.
- FB drivers
- - Add support for fbdev drivers.- Ready and part of subsequent patches.
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