To avoid ambiguity, the user sees 10 bit addresses mapped to a differentaddress space, namely 0xa000-0xa3ff. The leading 0xa (= 10) represents the10 bit mode. This is used for creating device names in sysfs. It is alsoneeded when instantiating 10 bit devices via the new_device file in sysfs.
The current 10 bit address support is minimal. It should work, howeveryou can expect some problems along the way:* Not all bus drivers support 10-bit addresses. Some don't because the hardware doesn't support them (SMBus doesn't require 10-bit address support for example), some don't because nobody bothered adding the code (or it's there but not working properly.) Software implementation (i2c-algo-bit) is known to work.* Some optional features do not support 10-bit addresses. This is the case of automatic detection and instantiation of devices by their, drivers, for example.* Many user-space packages (for example i2c-tools) lack support for 10-bit addresses.Note that 10-bit address devices are still pretty rare, so the limitationslisted above could stay for a long time, maybe even forever if nobodyneeds them to be fixed.