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    Subject[PATCH 3/4] i2c: omap: don't reset controller if Arbitration Lost detected
    Date
    Arbitration Lost is a expected situation in a multimaster environment.
    IP correctly detect it.

    The only reason for reseting IP in the AL case is to be sure to
    avoid advisory 1.94 (omap3) and errata i595 (omap4):
    "I2C: After an Arbitration is Lost the Module Incorrectly Starts
    the Next Transfer" with workaround: "The MST and STT bits inside
    I2C_CON should be set to 1 at the same moment (avoid setting the
    MST bit to 1 while STT = 0)."

    The driver never writes MST and STT bits separately and doesn't
    create condition for errata. So the reset is not necessary.

    Tested on Beagleboard XM C.

    Signed-off-by: Alexander Kochetkov <al.kochet@gmail.com>
    ---
    drivers/i2c/busses/i2c-omap.c | 6 +++++-
    1 file changed, 5 insertions(+), 1 deletion(-)

    diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
    index 3ffb9c0..47103e7 100644
    --- a/drivers/i2c/busses/i2c-omap.c
    +++ b/drivers/i2c/busses/i2c-omap.c
    @@ -707,13 +707,17 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
    return 0;

    /* We have an error */
    - if (dev->cmd_err & (OMAP_I2C_STAT_AL | OMAP_I2C_STAT_ROVR |
    + if (dev->cmd_err & (OMAP_I2C_STAT_ROVR |
    OMAP_I2C_STAT_XUDF)) {
    omap_i2c_reset(dev);
    __omap_i2c_init(dev);
    return -EIO;
    }

    + if (dev->cmd_err & OMAP_I2C_STAT_AL) {
    + return -EIO;
    + }
    +
    if (dev->cmd_err & OMAP_I2C_STAT_NACK) {
    if (msg->flags & I2C_M_IGNORE_NAK)
    return 0;
    --
    1.7.9.5


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