On Thu, Aug 26, 2021 at 07:46:32PM +0200, Tobias Schramm wrote: > Previously the SDA line sometimes remained stuck low after timeouts > rendering the I2C bus unusable. Testing has shown that disabling and > reenabling the I2C peripheral after sending the stop condition seems to > unstick SDA reliably. > Disable and reenable the I2C controller on timeout after sending stop > condition to unstick SDA. Does it also help to not send STOP? This looks a bit like a hack which went into the driver somehow. The proper solution might be to remove the STOP and add proper i2c_bus_recovery at the beginning of a transfer. > > Signed-off-by: Tobias Schramm <t.schramm@xxxxxxxxxxx> > --- > drivers/i2c/busses/i2c-rk3x.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c > index 819ab4ee517e..fc330cc3686a 100644 > --- a/drivers/i2c/busses/i2c-rk3x.c > +++ b/drivers/i2c/busses/i2c-rk3x.c > @@ -1108,6 +1108,16 @@ static int rk3x_i2c_xfer_common(struct i2c_adapter *adap, > val |= REG_CON_EN | REG_CON_STOP; > i2c_writel(i2c, val, REG_CON); > > + /* > + * Sometimes SDA remains stuck low after timeouts. > + * Disable and reenable the I2C peripheral to unstick > + * SDA. > + */ > + val &= ~REG_CON_EN; > + i2c_writel(i2c, val, REG_CON); > + val |= REG_CON_EN; > + i2c_writel(i2c, val, REG_CON); > + > i2c->state = STATE_IDLE; > > ret = -ETIMEDOUT; > -- > 2.31.1 >
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