tree 0888b4c9f17157dff5e0e30334d7dc6c666e9d06
parent d5b069ecb4199f1672fd98041bd0037bd33d2f0f
author Tom Rini <trini@ti.com> 1337582789 +0000
committer Albert ARIBAUD <albert.u.boot@aribaud.net> 1341662842 +0200

Revert "I2C: OMAP: detect more devices when probing an i2c bus"

This reverts commit 0e57968a215d1b9d271f3fa5bebeddeaea0c8075.

The short version of the original commit is that some i2c devices cannot
be probed via read as they NAK the first cycle, so try and probe via a
write that we abort before it writes to the device.  This however is not
allowed by the TRM for any of these parts.  The section on I2C_CON
(table 17-35 I2C_CON for am/dm37x for example) says you must not change
the register while STT has been set.  On these parts, the unpredictable
behavior that the chip exhibits is not problematic.  On OMAP4 however it
results in the chip being in a bad state:
Panda # i2c probe
Valid chip addresses: 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12
13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F 20 21 22 23 24 25 26 27 28 29 2A
2B 2C 2D 2E 2F 30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F 40 41 42
43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F 50 51 52 53 54 55 56 57 58 59 5A
5B 5C 5D 5E 5F 60 61 62 63 64 65 66 67 68 69 6A 6B 6C 6D 6E 6F 70 71 72
73 74 75 76 77 78 79 7A 7B 7C 7D 7E 7F
Panda # i2c md 50 0
timed out in wait_for_pin: I2C_STAT=0
I2C read: I/O error
Error reading the chip.

We must revert the original behavior to bring probe back into line with
the TRM.

Cc: Nick Thompson <nick.thompson@ge.com>
Cc: Heiko Schocher <hs@denx.de>
Signed-off-by: Tom Rini <trini@ti.com>
Acked-by: Heiko Schocher <hs@denx.de>