> -----Original Message-----
> From: Andi Shyti <andi.shyti@xxxxxxxxxx>
> Sent: 2024年9月13日 0:36
> To: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
> Cc: Liu Kimriver/刘金河 <kimriver.liu@xxxxxxxxxxxx>; jarkko.nikula@xxxxxxxxxxxxxxx; andriy.shevchenko@xxxxxxxxxxxxxxx; mika.westerberg@xxxxxxxxxxxxxxx; jsd@xxxxxxxxxxxx; linux-i2c@xxxxxxxxxxxxxxx; linux-> kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v10] i2c: designware: fix controller is holding SCL low while ENABLE bit is disabled
> 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.
OK，I agree with your fixing it before merging. Thanks for your review!
> > > + * 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
OK，I agree.
Do I still need to update to patch V11? Or you fix it before merging
Thanks for taking the time to review the patch, I have learned a lot of knowledge .
> > +}
>
> ...
>
> > + /*
> > + * 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
>
>
------------------------------------------
Best Regards
Kimriver Liu
