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Diffstat (limited to 'Documentation/i2c/ten-bit-addresses')
-rw-r--r-- | Documentation/i2c/ten-bit-addresses | 28 |
1 files changed, 0 insertions, 28 deletions
diff --git a/Documentation/i2c/ten-bit-addresses b/Documentation/i2c/ten-bit-addresses deleted file mode 100644 index 7b2d11e53a49..000000000000 --- a/Documentation/i2c/ten-bit-addresses +++ /dev/null @@ -1,28 +0,0 @@ -The I2C protocol knows about two kinds of device addresses: normal 7 bit -addresses, and an extended set of 10 bit addresses. The sets of addresses -do not intersect: the 7 bit address 0x10 is not the same as the 10 bit -address 0x10 (though a single device could respond to both of them). -To avoid ambiguity, the user sees 10 bit addresses mapped to a different -address space, namely 0xa000-0xa3ff. The leading 0xa (= 10) represents the -10 bit mode. This is used for creating device names in sysfs. It is also -needed when instantiating 10 bit devices via the new_device file in sysfs. - -I2C messages to and from 10-bit address devices have a different format. -See the I2C specification for the details. - -The current 10 bit address support is minimal. It should work, however -you 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 limitations -listed above could stay for a long time, maybe even forever if nobody -needs them to be fixed. |