Merge tag 'cpufreq-for-3.5-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git...

[karo-tx-linux.git] / Documentation / i2c / i2c-protocol

diff --git a/Documentation/i2c/i2c-protocol b/Documentation/i2c/i2c-protocol
index 579b92d5f3a38c4796d6bcf4c1de559277090974..0b3e62d1f77a1853765338afd9ed9d6ea56902d2 100644 (file)
--- a/Documentation/i2c/i2c-protocol
+++ b/Documentation/i2c/i2c-protocol
@@ -49,7 +49,9 @@ a byte read, followed by a byte write:
 Modified transactions
 =====================
 
 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
 
   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.
 
     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
   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


@@ -68,7 +75,7 @@ We have found some I2C devices that needs the following modifications:
 
   Flags I2C_M_IGNORE_NAK
     Normally message is interrupted immediately if there is [NA] from the
 
   Flags I2C_M_IGNORE_NAK
     Normally message is interrupted immediately if there is [NA] from the

-    client. Setting this flag treats any [NA] as [A], and all of
+    client. Setting this flag treats any [NA] as [A], and all of

     message is sent.
     These messages may still fail to SCL lo->hi timeout.
 
     message is sent.
     These messages may still fail to SCL lo->hi timeout.