From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- Documentation/i2c/busses/i2c-voodoo3 | 62 ++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) create mode 100644 Documentation/i2c/busses/i2c-voodoo3 (limited to 'Documentation/i2c/busses/i2c-voodoo3') diff --git a/Documentation/i2c/busses/i2c-voodoo3 b/Documentation/i2c/busses/i2c-voodoo3 new file mode 100644 index 000000000000..62d90a454d39 --- /dev/null +++ b/Documentation/i2c/busses/i2c-voodoo3 @@ -0,0 +1,62 @@ +Kernel driver i2c-voodoo3 + +Supported adapters: + * 3dfx Voodoo3 based cards + * Voodoo Banshee based cards + +Authors: + Frodo Looijaard , + Philip Edelbrock , + Ralph Metzler , + Mark D. Studebaker + +Main contact: Philip Edelbrock + +The code is based upon Ralph's test code (he did the hard stuff ;') + +Description +----------- + +The 3dfx Voodoo3 chip contains two I2C interfaces (aka a I2C 'master' or +'host'). + +The first interface is used for DDC (Data Display Channel) which is a +serial channel through the VGA monitor connector to a DDC-compliant +monitor. This interface is defined by the Video Electronics Standards +Association (VESA). The standards are available for purchase at +http://www.vesa.org . + +The second interface is a general-purpose I2C bus. The intent by 3dfx was +to allow manufacturers to add extra chips to the video card such as a +TV-out chip such as the BT869 or possibly even I2C based temperature +sensors like the ADM1021 or LM75. + +Stability +--------- + +Seems to be stable on the test machine, but needs more testing on other +machines. Simultaneous accesses of the DDC and I2C busses may cause errors. + +Supported Devices +----------------- + +Specifically, this driver was written and tested on the '3dfx Voodoo3 AGP +3000' which has a tv-out feature (s-video or composite). According to the +docs and discussions, this code should work for any Voodoo3 based cards as +well as Voodoo Banshee based cards. The DDC interface has been tested on a +Voodoo Banshee card. + +Issues +------ + +Probably many, but it seems to work OK on my system. :') + + +External Device Connection +-------------------------- + +The digital video input jumpers give availability to the I2C bus. +Specifically, pins 13 and 25 (bottom row middle, and bottom right-end) are +the I2C clock and I2C data lines, respectively. +5V and GND are probably +also easily available making the addition of extra I2C/SMBus devices easy +to implement. -- cgit v1.2.1