On Thu, Sep 12, 2024 at 06:32:48PM GMT, Andy Shevchenko wrote:
> Thu, Sep 12, 2024 at 02:11:12PM +0800, Kimriver Liu kirjoitti:
> > It was observed that issuing ABORT bit (IC_ENABLE[1]) will not
> > work when IC_ENABLE is already disabled.
> >
> > Check if ENABLE bit (IC_ENABLE[0]) is disabled when the controller
> > is holding SCL low. If ENABLE bit is disabled, the software need
/need/needs/
> > to enable it before trying to issue ABORT bit. otherwise,
/ABORT/the ABORT/
> > the controller ignores any write to ABORT bit.
> >
> > These kernel logs show up whenever an I2C transaction is
> > attempted after this failure.
> > i2c_designware e95e0000.i2c: timeout waiting for bus ready
> > i2c_designware e95e0000.i2c: timeout in disabling adapter
>
> > The patch can be fix the controller cannot be disabled while
> > SCL is held low in ENABLE bit is already disabled.
>
> There are English words but a complete nonsense together.
We could reword this to:
The patch fixes the issue where the controller cannot be disabled
while SCL is held low if the ENABLE bit is already disabled.
> Fix the condition when controller cannot be disabled while SCL
/when/where/
> is held low and ENABLE bit is already disabled.
/ENABLE/the ENABLE/
If you agree with the changes, I can apply them before merging.
>
> Reviewed-by: Andy Shevchenko <andy@xxxxxxxxxx>
Thanks a lot, Andy! I really appreciate your reviews!
> ...
>
> > + if (!(enable & DW_IC_ENABLE_ENABLE)) {
> > + regmap_write(dev->map, DW_IC_ENABLE, DW_IC_ENABLE_ENABLE);
> > + /*
> > + * Wait 10 times the signaling period of the highest I2C
> > + * transfer supported by the driver (for 400KHz this is
> > + * 25us) to ensure the I2C ENABLE bit is already set
> > + * as described in the DesignWare I2C databook.
> > + */
> > + fsleep(DIV_ROUND_CLOSEST_ULL(10 * MICRO, t->bus_freq_hz));
>
> > + /* Keep ENABLE bit is already set before Setting ABORT.*/
>
> /* Set ENABLE bit before setting ABORT */
>
>
> > + enable |= DW_IC_ENABLE_ENABLE;
> > + }
>
> ...
>
> > +/*
> > + * This functions waits controller idling before disabling I2C
>
> s/functions/function/
I can fix it before merging.
> > + * When the controller is not in the IDLE state,
> > + * MST_ACTIVITY bit (IC_STATUS[5]) is set.
> > + * Values:
> > + * 0x1 (ACTIVE): Controller not idle
> > + * 0x0 (IDLE): Controller is idle
> > + * The function is called after returning the end of the current transfer
> > + * Returns:
> > + * False when controller is in IDLE state.
> > + * True when controller is in ACTIVE state.
> > + */
> > +static bool i2c_dw_is_controller_active(struct dw_i2c_dev *dev)
> > +{
> > + u32 status;
> > +
> > + regmap_read(dev->map, DW_IC_STATUS, &status);
> > + if (!(status & DW_IC_STATUS_MASTER_ACTIVITY))
> > + return false;
> > +
> > + return regmap_read_poll_timeout(dev->map, DW_IC_STATUS, status,
> > + !(status & DW_IC_STATUS_MASTER_ACTIVITY),
> > + 1100, 20000) != 0;
>
> return regmap_read_poll_timeout(dev->map, DW_IC_STATUS, status,
> !(status & DW_IC_STATUS_MASTER_ACTIVITY),
> 1100, 20000) != 0;
>
> (in the second line replaced 7 spaces by a single TAB to fix the indentation)
I can fix it before merging.
Kimriver, if you agree, i can merge this and queue it for the
next week's fixes merge request.
Andi
> > +}
>
> ...
>
> > + /*
> > + * This happens rarely (~1:500) and is hard to reproduce. Debug trace
> > + * showed that IC_STATUS had value of 0x23 when STOP_DET occurred,
> > + * if disable IC_ENABLE.ENABLE immediately that can result in
> > + * IC_RAW_INTR_STAT.MASTER_ON_HOLD holding SCL low. Check if
> > + * controller is still ACTIVE before disabling I2C.
> > + */
> > + if (i2c_dw_is_controller_active(dev))
> > + dev_err(dev->dev, "controller active\n");
>
> --
> With Best Regards,
> Andy Shevchenko
>
>
