Based on kernel version 3.19. Page generated on 2015-02-13 21:21 EST.
1 The I2C protocol knows about two kinds of device addresses: normal 7 bit 2 addresses, and an extended set of 10 bit addresses. The sets of addresses 3 do not intersect: the 7 bit address 0x10 is not the same as the 10 bit 4 address 0x10 (though a single device could respond to both of them). 5 6 I2C messages to and from 10-bit address devices have a different format. 7 See the I2C specification for the details. 8 9 The current 10 bit address support is minimal. It should work, however 10 you can expect some problems along the way: 11 * Not all bus drivers support 10-bit addresses. Some don't because the 12 hardware doesn't support them (SMBus doesn't require 10-bit address 13 support for example), some don't because nobody bothered adding the 14 code (or it's there but not working properly.) Software implementation 15 (i2c-algo-bit) is known to work. 16 * Some optional features do not support 10-bit addresses. This is the 17 case of automatic detection and instantiation of devices by their, 18 drivers, for example. 19 * Many user-space packages (for example i2c-tools) lack support for 20 10-bit addresses. 21 22 Note that 10-bit address devices are still pretty rare, so the limitations 23 listed above could stay for a long time, maybe even forever if nobody 24 needs them to be fixed.