1Kernel driver i2c-voodoo3 2 3Supported adapters: 4 * 3dfx Voodoo3 based cards 5 * Voodoo Banshee based cards 6 7Authors: 8 Frodo Looijaard <frodol@dds.nl>, 9 Philip Edelbrock <phil@netroedge.com>, 10 Ralph Metzler <rjkm@thp.uni-koeln.de>, 11 Mark D. Studebaker <mdsxyz123@yahoo.com> 12 13Main contact: Philip Edelbrock <phil@netroedge.com> 14 15The code is based upon Ralph's test code (he did the hard stuff ;') 16 17Description 18----------- 19 20The 3dfx Voodoo3 chip contains two I2C interfaces (aka a I2C 'master' or 21'host'). 22 23The first interface is used for DDC (Data Display Channel) which is a 24serial channel through the VGA monitor connector to a DDC-compliant 25monitor. This interface is defined by the Video Electronics Standards 26Association (VESA). The standards are available for purchase at 27http://www.vesa.org . 28 29The second interface is a general-purpose I2C bus. The intent by 3dfx was 30to allow manufacturers to add extra chips to the video card such as a 31TV-out chip such as the BT869 or possibly even I2C based temperature 32sensors like the ADM1021 or LM75. 33 34Stability 35--------- 36 37Seems to be stable on the test machine, but needs more testing on other 38machines. Simultaneous accesses of the DDC and I2C busses may cause errors. 39 40Supported Devices 41----------------- 42 43Specifically, this driver was written and tested on the '3dfx Voodoo3 AGP 443000' which has a tv-out feature (s-video or composite). According to the 45docs and discussions, this code should work for any Voodoo3 based cards as 46well as Voodoo Banshee based cards. The DDC interface has been tested on a 47Voodoo Banshee card. 48 49Issues 50------ 51 52Probably many, but it seems to work OK on my system. :') 53 54 55External Device Connection 56-------------------------- 57 58The digital video input jumpers give availability to the I2C bus. 59Specifically, pins 13 and 25 (bottom row middle, and bottom right-end) are 60the I2C clock and I2C data lines, respectively. +5V and GND are probably 61also easily available making the addition of extra I2C/SMBus devices easy 62to implement. 63