Hello Tom, Tom Rini wrote: > 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.thomp...@ge.com> > Cc: Heiko Schocher <h...@denx.de> > Signed-off-by: Tom Rini <tr...@ti.com> > --- > drivers/i2c/omap24xx_i2c.c | 42 +++++++++++++++++++++++++++++++----------- > 1 file changed, 31 insertions(+), 11 deletions(-)
Acked-by: Heiko Schocher <h...@denx.de> Thanks! bye, Heiko -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: w...@denx.de _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
