|VPBE V4L2 driver design
|V4L2 display device driver
|VPBE display controller
|VPBE venc sub device driver
|VPBE osd driver
|Consists of the following (in the same order as the list under file
|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
|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
|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.
|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.
|- Add support for fbdev drivers.- Ready and part of subsequent patches.