Re: [PATCH] i2c: designware: add a new bit check for IC_CON control

[Shyam Sundar S K <Shyam-sundar.S-k@amd.com>]

On 1/17/2023 4:51 PM, Jarkko Nikula wrote:
> On 1/17/23 12:38, Andy Shevchenko wrote:
>> On Tue, Jan 17, 2023 at 04:01:21PM +0530, Shyam Sundar S K wrote:
>>> Double checked with our HW and FW teams, and understand that (atleast in
>>> AMD platform designs):
>>>
>>> 1. BIOS actually programs the BUS_CLEAR_FEATURE_CTRL and also enables
>>> the detection of SCL/SDA stuck low.
>>> 2. Whenever the stuck low is detected, the SMU FW shall do the bus
>>> recovery procedure.
>>>
>>> Currently, the way in which the "master_cfg" is built in the driver it
>>> overrides the BUS_CLEAR_FEATURE_CTRL advertised by BIOS and the SMU FW
>>> cannot initiate the bus recovery if the stuck low is detected.
>>>
>>> Hence this proposed check should be sufficient enough.
>>
>> Maybe you should elaborate this in the commit message and/or the code.
>>
> Yes indeed. Makes obvious this is not dead code if somebody looks only
> the code and specification.
> 
> It is also important in the future if somebody adds the same
> functionality into driver that this AMD platform must be taken into
> account in that code change. I.e. no two instances trying to do the same
> recovery.

Makes sense. Shall re-spin a v2 with the commit message edits.

Thanks,
Shyam