I2C instability

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At IRC

http://www.beagleboard.org/irclogs/index.php?date=2008-07-12#T13:06:48

koen and sakoman report "I2C strangeness" and "i2c goes wonky" at Beagle
board, e.g. using ASOC. At EVM this doesn't happen.

Original issue reported on code.google.com by dirk.be...@gmail.com on 12 Jul 2008 at 1:21

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Note: There is an additional I2C issue #17

http://code.google.com/p/beagleboard/issues/detail?id=17

This should be independent of #17: #17 is about I2C2 timeouts with Beagle's
unconnected expansion header while this seems to be about broken I2C 
communication.

Original comment by dirk.be...@gmail.com on 12 Jul 2008 at 1:24

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Original comment by jkrid...@gmail.com on 16 Jul 2008 at 7:29

• Added labels: Priority-Critical
• Removed labels: Priority-High

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Currently, it is assumed that the following patches fix *kernel* issues:

http://marc.info/?l=linux-omap&m=121614853008185&w=2

http://www.pwsan.com/omap/read_write_twl4030_isrs_to_clear.patch

The second patch switches I2C1 speed from 2.6MHz down to 400KHz, too. It is 
currently
investigated if this is necessary.

Note: These patches are for *kernel*. *U-Boot* (V1) messages like

-- cut --
U-Boot 1.3.3-rc3-00062-ga38dc3e-dirty (May 17 2008 - 07:34:07)
OMAP3430-GP rev 2, CPU-OPP2 L3-133MHz
OMAP3 Beagle Board 2.0 Version + mDDR (Boot ONND)
DRAM:  128 MB
NAND:  256 MiB
In:    serial
Out:   serial
Err:   serial
timed out in wait_for_bb: I2C_STAT=1000
timed out in wait_for_bb: I2C_STAT=1000
timed out in wait_for_bb: I2C_STAT=1000
timed out in wait_for_pin: I2C_STAT=1000
I2C read: I/O error
timed out in wait_for_bb: I2C_STAT=1000
timed out in wait_for_bb: I2C_STAT=1000
Audio Tone on Speakerstimed out in wait_for_bb: I2C_STAT=1000
timed out in wait_for_pin: I2C_STAT=1000
I2C read: I/O error
timed out in wait_for_bb: I2C_STAT=1000
...
-- cut -- 

are assumed to be *compiler* related! CSL 2008Q1 results in above uboot I2C 
timeouts.
So use 2007Q3/Q1 for uboot (V1).

Original comment by dirk.be...@gmail.com on 17 Jul 2008 at 3:18

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Above patches are updated on OMAP mailing list. Now use

http://marc.info/?l=linux-omap&m=121614853008185&w=2

http://marc.info/?l=linux-omap&m=121634494302972&w=2 (9 patches)

Original comment by dirk.be...@gmail.com on 19 Jul 2008 at 5:19

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Fixed with TWL4030 patch series starting with

http://source.mvista.com/git/?p=linux-omap-2.6.git;a=commit;h=4866d0e5718cfa7bc1
b4442d5625dce08203f201

Original comment by dirk.be...@gmail.com on 5 Aug 2008 at 6:29

• Changed state: Fixed