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1The I2C protocol knows about two kinds of device addresses: normal 7 bit
2addresses, and an extended set of 10 bit addresses. The sets of addresses
3do not intersect: the 7 bit address 0x10 is not the same as the 10 bit
4address 0x10 (though a single device could respond to both of them).
5
6I2C messages to and from 10-bit address devices have a different format.
7See the I2C specification for the details.
8
9The current 10 bit address support is minimal. It should work, however
10you 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
22Note that 10-bit address devices are still pretty rare, so the limitations
23listed above could stay for a long time, maybe even forever if nobody
24needs them to be fixed.