RE: [PATCH v9] i2c: designware: fix controller is holding SCL low while ENABLE bit is disabled

[Liu Kimriver/刘金河]

HI andi and andy,

>-----Original Message-----
>From: Andi Shyti <andi.shyti@xxxxxxxxxx> 
>Sent: 2024年9月11日 18:16
>To: Liu Kimriver/刘金河 <kimriver.liu@xxxxxxxxxxxx>
>Cc: jarkko.nikula@xxxxxxxxxxxxxxx; andriy.shevchenko@xxxxxxxxxxxxxxx; mika.westerberg@xxxxxxxxxxxxxxx; jsd@xxxxxxxxxxxx; linux-i2c@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
>Subject: Re: [PATCH v9] i2c: designware: fix controller is holding SCL low while ENABLE bit is disabled

>Andy,

>On Wed, Sep 11, 2024 at 04:39:45PM GMT, Kimriver Liu wrote:
>> 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
>> to enable it before trying to issue ABORT bit. otherwise,
>> 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.
>> 
>> Fixes: 2409205acd3c ("i2c: designware: fix __i2c_dw_disable() in case master is holding SCL low")
>> Signed-off-by: Kimriver Liu <kimriver.liu@xxxxxxxxxxxx>
>> Reviewed-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
>> Acked-by: Jarkko Nikula <jarkko.nikula@xxxxxxxxxxxxxxx>

>if you're happe, I would take this in.

>Thanks Kimriver for following up on all the reviews, I really
>appreciate your responsivness.

 Thanks for the review!

 I have done the testing of the V9 patch on our product , it Verified successful when controller is holding SCL low.

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Best Regards
Kimriver Liu