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author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-05-30 10:03:46 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-05-30 10:03:46 -0700 |
commit | 42fe55ce905212542426fa6407a76534a5fb696a (patch) | |
tree | 874c5984e4222ea253b78c5be4755b3d31da54e2 /Documentation/i2c/i2c-protocol | |
parent | 19ce0a995ff230b364c7329fd488c70e91c171d9 (diff) | |
parent | 14674e70119ea01549ce593d8901a797f8a90f74 (diff) | |
download | blackbird-op-linux-42fe55ce905212542426fa6407a76534a5fb696a.tar.gz blackbird-op-linux-42fe55ce905212542426fa6407a76534a5fb696a.zip |
Merge branch 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging
Pull i2c updates from Jean Delvare.
* 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
i2c: Split I2C_M_NOSTART support out of I2C_FUNC_PROTOCOL_MANGLING
i2c-dev: Add support for I2C_M_RECV_LEN
Diffstat (limited to 'Documentation/i2c/i2c-protocol')
-rw-r--r-- | Documentation/i2c/i2c-protocol | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/Documentation/i2c/i2c-protocol b/Documentation/i2c/i2c-protocol index 10518dd58814..0b3e62d1f77a 100644 --- a/Documentation/i2c/i2c-protocol +++ b/Documentation/i2c/i2c-protocol @@ -49,7 +49,9 @@ a byte read, followed by a byte write: Modified transactions ===================== -We have found some I2C devices that needs the following modifications: +The following modifications to the I2C protocol can also be generated, +with the exception of I2C_M_NOSTART these are usually only needed to +work around device issues: Flag I2C_M_NOSTART: In a combined transaction, no 'S Addr Wr/Rd [A]' is generated at some @@ -60,6 +62,11 @@ We have found some I2C devices that needs the following modifications: we do not generate Addr, but we do generate the startbit S. This will probably confuse all other clients on your bus, so don't try this. + This is often used to gather transmits from multiple data buffers in + system memory into something that appears as a single transfer to the + I2C device but may also be used between direction changes by some + rare devices. + Flags I2C_M_REV_DIR_ADDR This toggles the Rd/Wr flag. That is, if you want to do a write, but need to emit an Rd instead of a Wr, or vice versa, you set this |