From f9aa6a1086f6b7da1814a2c95feefa91c9c4b593 Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Wed, 26 Feb 2014 15:59:27 -0700 Subject: dm: Remove old driver model documentation This documentation pertains to the planned implementation of driver model in U-Boot for each subsystem, but it has not been superseded. It is probably better to have this documentation in the source code for each subsystem where possible, so that docbook will pick it up. Where this does not make sense, new documentation can be placed in some suitable file in doc/driver-model. Signed-off-by: Simon Glass --- doc/driver-model/UDM-video.txt | 74 ------------------------------------------ 1 file changed, 74 deletions(-) delete mode 100644 doc/driver-model/UDM-video.txt (limited to 'doc/driver-model/UDM-video.txt') diff --git a/doc/driver-model/UDM-video.txt b/doc/driver-model/UDM-video.txt deleted file mode 100644 index e67e9e4..0000000 --- a/doc/driver-model/UDM-video.txt +++ /dev/null @@ -1,74 +0,0 @@ -The U-Boot Driver Model Project -=============================== -Video output analysis -===================== -Marek Vasut -2012-02-20 - -I) Overview ------------ - -The video drivers are most often registered with video subsystem. This subsystem -often expects to be allowed access to framebuffer of certain parameters. This -subsystem also provides calls for STDIO subsystem to allow it to output -characters on the screen. For this part, see [ UDM-stdio.txt ]. - -Therefore the API has two parts, the video driver part and the part where the -video driver core registers with STDIO API. - -The video driver part will follow the current cfb_console approach, though -allowing it to be more dynamic. - -II) Approach ------------- - -Registering the video driver into the video driver core is done by calling the -following function from the driver probe() function: - - video_device_register(struct instance *i, GraphicDevice *gd); - -Because the video driver core is in charge or rendering characters as well as -bitmaps on the screen, it will in turn call stdio_device_register(i, so), where -"i" is the same instance as the video driver's one. But "so" will be special -static struct stdio_device_ops handling the character output. - - -III) Analysis of in-tree drivers --------------------------------- - - arch/powerpc/cpu/mpc8xx/video.c - ------------------------------- - This driver copies the cfb_console [ see drivers/video/cfb_console.c ] - approach and acts only as a STDIO device. Therefore there are currently two - possible approaches, first being the conversion of this driver to usual STDIO - device and second, long-term one, being conversion of this driver to video - driver that provides console. - - arch/x86/lib/video.c - -------------------- - This driver registers two separate STDIO devices and should be therefore - converted as such. - - board/bf527-ezkit/video.c - ------------------------- - This driver seems bogus as it behaves as STDIO device, but provides no input - or output capabilities. It relies on DEV_EXT_VIDEO, which is no longer in use - or present otherwise than as a dead code/define. - - board/bf533-stamp/video.c - ------------------------- - This driver seems bogus as it behaves as STDIO device, but provides no input - or output capabilities. It relies on DEV_EXT_VIDEO, which is no longer in use - or present otherwise than as a dead code/define. - - board/bf548-ezkit/video.c - ------------------------- - This driver seems bogus as it behaves as STDIO device, but provides no input - or output capabilities. It relies on DEV_EXT_VIDEO, which is no longer in use - or present otherwise than as a dead code/define. - - board/cm-bf548/video.c - ---------------------- - This driver seems bogus as it behaves as STDIO device, but provides no input - or output capabilities. It relies on DEV_EXT_VIDEO, which is no longer in use - or present otherwise than as a dead code/define. -- cgit v1.1