Re: [PATCH v3 4/5] i2c: davinci: use bus recovery infrastructure

From: Wolfram Sang
Date: Wed Mar 18 2015 - 16:31:38 EST


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.

> @@ -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...

Thanks,

Wolfram

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