Commit graph

6 commits

Author SHA1 Message Date
Jean Delvare
b5527a7766 i2c: Add SMBus alert support
SMBus alert support. The SMBus alert protocol allows several SMBus
slave devices to share a single interrupt pin on the SMBus master,
while still allowing the master to know which slave triggered the
interrupt.

This is based on preliminary work by David Brownell. The key
difference between David's implementation and mine is that his was
part of i2c-core, while mine is split into a separate, standalone
module named i2c-smbus. The i2c-smbus module is meant to include
support for all SMBus extensions to the I2C protocol in the future.

The benefit of this approach is a zero cost for I2C bus segments which
do not need SMBus alert support. Where David's implementation
increased the size of struct i2c_adapter by 7% (40 bytes on i386),
mine doesn't touch it. Where David's implementation added over 150
lines of code to i2c-core (+10%), mine doesn't touch it. The only
change that touches all the users of the i2c subsystem is a new
callback in struct i2c_driver (common to both implementations.) I seem
to remember Trent was worried about the footprint of David'd
implementation, hopefully mine addresses the issue.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Trent Piepho <tpiepho@freescale.com>
2010-03-02 12:23:42 +01:00
Prakash Mortha
596c88f460 i2c: Restore i2c_smbus_process_call function
Restore the i2c_smbus_process_call() as one driver (for the
Micronas MAP5401) will need it soon.

[JD: Update documentation accordingly.]

Signed-off-by: Prakash Mortha <pmortha@escient.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2008-10-14 17:30:06 +02:00
Jean Delvare
67c2e66571 i2c: Delete unused function i2c_smbus_write_quick
Function i2c_smbus_write_quick has no users left, so we can delete it.

Also update the list of these helper functions which are gone but
could be added back if needed.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
2008-07-14 22:38:23 +02:00
David Brownell
1a31a88f4f i2c: Improve smbus-protocol documentation
Improve the smbus-protocol documentation file somewhat:

 - Use the names of the SMBus protocol operations (from the 2.0
   specification), not made-up-for-Linux names.

 - Add the name of the call used to execute each operation ... and
   point out that there are mismatches, where functions execute
   different protocol operations than their names specify.
   
The most confusing examples are that "Read Byte" isn't executed by
i2c_smbus_read_byte(), and that "Write Byte" isn't executed by
i2c_smbus_write_byte().  When coding, that's not as bad as it may
seem; but that case would seem to be worth fixing.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2008-05-11 20:37:05 +02:00
Mike Frysinger
3f9a4790a3 i2c: Fix typo in SMBus Write Word Data description
Write data, don't read it.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-02-13 22:08:59 +01:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00