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    SubjectRe: [PATCH v3 4/5] i2c: davinci: use bus recovery infrastructure
    Hi,
    On 03/18/2015 10:31 PM, Wolfram Sang wrote:
    > Hi,
    >
    > so, the bus recovery patches look fine to me in general.
    >
    > It is only this one question left which I always had with bus recovery.
    > Maybe you guys can join me thinking about it.

    Ok. Thanks and sorry for delayed reply - missed your e-mail :(
    I'll resend them next week.

    >
    >> @@ -376,8 +366,7 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
    >> dev->adapter.timeout);
    >> if (r == 0) {
    >> dev_err(dev->dev, "controller timed out\n");
    >> - davinci_i2c_recover_bus(dev);
    >> - i2c_davinci_init(dev);
    >> + i2c_recover_bus(adap);
    >> dev->buf_len = 0;
    >> return -ETIMEDOUT;
    >
    > The I2C specs say in 3.1.16 that the recovery procedure should be used
    > when SDA is stuck low. So, I do wonder if we should apply the recovery
    > after a timeout. Stuck SDA might be one reason for timeout, but there
    > may be others...

    This is ancient code. And regarding your question -
    Might be it would be reasonable to add call of
    i2c_davinci_wait_bus_not_busy() at the end of i2c_davinci_xfer()?
    This way we will wait for Bus Free before performing recovery.

    Of course, i2c_davinci_wait_bus_not_busy() has to be fixed first
    as proposed by Alexander Sverdlin here:
    https://patchwork.ozlabs.org/patch/448994/.

    --
    regards,
    -grygorii


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