Based on kernel version 4.7.2. Page generated on 2016-08-22 22:48 EST.
1 2 VPBE V4L2 driver design 3 ====================================================================== 4 5 File partitioning 6 ----------------- 7 V4L2 display device driver 8 drivers/media/platform/davinci/vpbe_display.c 9 drivers/media/platform/davinci/vpbe_display.h 10 11 VPBE display controller 12 drivers/media/platform/davinci/vpbe.c 13 drivers/media/platform/davinci/vpbe.h 14 15 VPBE venc sub device driver 16 drivers/media/platform/davinci/vpbe_venc.c 17 drivers/media/platform/davinci/vpbe_venc.h 18 drivers/media/platform/davinci/vpbe_venc_regs.h 19 20 VPBE osd driver 21 drivers/media/platform/davinci/vpbe_osd.c 22 drivers/media/platform/davinci/vpbe_osd.h 23 drivers/media/platform/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.