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+
+ VPBE V4L2 driver design
+ ======================================================================
+
+ File partitioning
+ -----------------
+ V4L2 display device driver
+ drivers/media/video/davinci/vpbe_display.c
+ drivers/media/video/davinci/vpbe_display.h
+
+ VPBE display controller
+ drivers/media/video/davinci/vpbe.c
+ drivers/media/video/davinci/vpbe.h
+
+ VPBE venc sub device driver
+ drivers/media/video/davinci/vpbe_venc.c
+ drivers/media/video/davinci/vpbe_venc.h
+ drivers/media/video/davinci/vpbe_venc_regs.h
+
+ VPBE osd driver
+ drivers/media/video/davinci/vpbe_osd.c
+ drivers/media/video/davinci/vpbe_osd.h
+ drivers/media/video/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.