| Manjunath Hadli | af60313 | 2011-06-17 04:01:36 -0300 | [diff] [blame] | 1 | |
| 2 | VPBE V4L2 driver design |
| 3 | ====================================================================== |
| 4 | |
| 5 | File partitioning |
| 6 | ----------------- |
| 7 | V4L2 display device driver |
| 8 | drivers/media/video/davinci/vpbe_display.c |
| 9 | drivers/media/video/davinci/vpbe_display.h |
| 10 | |
| 11 | VPBE display controller |
| 12 | drivers/media/video/davinci/vpbe.c |
| 13 | drivers/media/video/davinci/vpbe.h |
| 14 | |
| 15 | VPBE venc sub device driver |
| 16 | drivers/media/video/davinci/vpbe_venc.c |
| 17 | drivers/media/video/davinci/vpbe_venc.h |
| 18 | drivers/media/video/davinci/vpbe_venc_regs.h |
| 19 | |
| 20 | VPBE osd driver |
| 21 | drivers/media/video/davinci/vpbe_osd.c |
| 22 | drivers/media/video/davinci/vpbe_osd.h |
| 23 | drivers/media/video/davinci/vpbe_osd_regs.h |
| 24 | |
| 25 | Functional partitioning |
| 26 | ----------------------- |
| 27 | |
| 28 | Consists of the following (in the same order as the list under file |
| 29 | partitioning):- |
| 30 | |
| 31 | 1. V4L2 display driver |
| 32 | Implements creation of video2 and video3 device nodes and |
| 33 | provides v4l2 device interface to manage VID0 and VID1 layers. |
| 34 | |
| 35 | 2. Display controller |
| 36 | Loads up VENC, OSD and external encoders such as ths8200. It provides |
| 37 | a set of API calls to V4L2 drivers to set the output/standards |
| 38 | in the VENC or external sub devices. It also provides |
| 39 | a device object to access the services from OSD subdevice |
| 40 | using sub device ops. The connection of external encoders to VENC LCD |
| 41 | controller port is done at init time based on default output and standard |
| 42 | selection or at run time when application change the output through |
| 43 | V4L2 IOCTLs. |
| 44 | |
| 45 | When connected to an external encoder, vpbe controller is also responsible |
| 46 | for setting up the interface between VENC and external encoders based on |
| 47 | board specific settings (specified in board-xxx-evm.c). This allows |
| 48 | interfacing external encoders such as ths8200. The setup_if_config() |
| 49 | is implemented for this as well as configure_venc() (part of the next patch) |
| 50 | API to set timings in VENC for a specific display resolution. As of this |
| 51 | patch series, the interconnection and enabling and setting of the external |
| 52 | encoders is not present, and would be a part of the next patch series. |
| 53 | |
| 54 | 3. VENC subdevice module |
| 55 | Responsible for setting outputs provided through internal DACs and also |
| 56 | setting timings at LCD controller port when external encoders are connected |
| 57 | at the port or LCD panel timings required. When external encoder/LCD panel |
| 58 | is connected, the timings for a specific standard/preset is retrieved from |
| 59 | the board specific table and the values are used to set the timings in |
| 60 | venc using non-standard timing mode. |
| 61 | |
| 62 | Support LCD Panel displays using the VENC. For example to support a Logic |
| 63 | PD display, it requires setting up the LCD controller port with a set of |
| 64 | timings for the resolution supported and setting the dot clock. So we could |
| 65 | add the available outputs as a board specific entry (i.e add the "LogicPD" |
| 66 | output name to board-xxx-evm.c). A table of timings for various LCDs |
| 67 | supported can be maintained in the board specific setup file to support |
| 68 | various LCD displays.As of this patch a basic driver is present, and this |
| 69 | support for external encoders and displays forms a part of the next |
| 70 | patch series. |
| 71 | |
| 72 | 4. OSD module |
| 73 | OSD module implements all OSD layer management and hardware specific |
| 74 | features. The VPBE module interacts with the OSD for enabling and |
| 75 | disabling appropriate features of the OSD. |
| 76 | |
| 77 | Current status:- |
| 78 | |
| 79 | A fully functional working version of the V4L2 driver is available. This |
| 80 | driver has been tested with NTSC and PAL standards and buffer streaming. |
| 81 | |
| 82 | Following are TBDs. |
| 83 | |
| 84 | vpbe display controller |
| 85 | - Add support for external encoders. |
| 86 | - add support for selecting external encoder as default at probe time. |
| 87 | |
| 88 | vpbe venc sub device |
| 89 | - add timings for supporting ths8200 |
| 90 | - add support for LogicPD LCD. |
| 91 | |
| 92 | FB drivers |
| 93 | - Add support for fbdev drivers.- Ready and part of subsequent patches. |