Documentation/i2c/ten-bit-addresses.rst

2 I2C Ten-bit Addresses
5 The I2C protocol knows about two kinds of device addresses: normal 7 bit
6 addresses, and an extended set of 10 bit addresses. The sets of addresses
7 do not intersect: the 7 bit address 0x10 is not the same as the 10 bit
9 To avoid ambiguity, the user sees 10 bit addresses mapped to a different
10 address space, namely 0xa000-0xa3ff. The leading 0xa (= 10) represents the
11 10 bit mode. This is used for creating device names in sysfs. It is also
12 needed when instantiating 10 bit devices via the new_device file in sysfs.
14 I2C messages to and from 10-bit address devices have a different format.
17 The current 10 bit address support is minimal. It should work, however
20 * Not all bus drivers support 10-bit addresses. Some don't because the
21   hardware doesn't support them (SMBus doesn't require 10-bit address
24   (i2c-algo-bit) is known to work.
25 * Some optional features do not support 10-bit addresses. This is the
28 * Many user-space packages (for example i2c-tools) lack support for
29   10-bit addresses.
31 Note that 10-bit address devices are still pretty rare, so the limitations