Re: [PATCH v4 3/3] i2c: qcom-geni: Add bus recovery support for GPI DMA mode

[Mukesh Savaliya <mukesh.savaliya@oss.qualcomm.com>]

On 11/3/2026 4:46 PM, Aniket RANDIVE wrote:
> 
> 
> On 11/3/2026 4:14 PM, Mukesh Savaliya wrote:
>>
>>
>> On 11/3/2026 2:26 PM, Aniket Randive wrote:
>>> I2C transfers in GPI DMA mode can fail with -EIO when a target holds
>>> SDA low, leaving the bus stuck and preventing subsequent transactions.
>>> The GPI completion callback reports a NACK and a genuine bus error
>>> alike as -EIO, and the existing recovery path switches the SE to FIFO
>>> mode which is not valid in GPI DMA mode.
>>>
>>> Add bus recovery support using the I2C_BUS_CLEAR and I2C_STOP_ON_BUS
>>> opcodes issued via the GPI TX DMA channel. Guard the -EIO recovery
>>> trigger with a SE_GENI_IOS I2C_BUS_FREE check to skip recovery when both
>>> SDA and SCL are already released. Extend the recovery callback to 
>>> dispatch
>>> through the GPI DMA path when gi2c->gpi_mode is set.
>>>
>>> Use the adapter timeout for GPI recovery commands, and preserve the DMA
>>> configuration error code when GPI setup fails.
>>>
>>> Stop recovery on a GPI command timeout and report DMA termination
>>> failures. Do not issue another command or override the timeout with a
>>> bus-idle result, since DMA cleanup may not have completed successfully.
>>>
>>> Signed-off-by: Aniket Randive <aniket.randive@oss.qualcomm.com>
>>> ---
>>>   drivers/i2c/busses/i2c-qcom-geni.c | 107 ++++++++++++++++++++++++++ 
>>> + +++++-----
>>>   1 file changed, 94 insertions(+), 13 deletions(-)
>>>
>>> diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/ 
>>> i2c-qcom-geni.c
>>
>> [...]
>>
>>> @@ -1356,10 +1439,8 @@ static int geni_i2c_probe(struct 
>>> platform_device *pdev)
>>>       if (ret < 0)
>>>           return ret;
>>> -    if (!gi2c->gpi_mode) {
>>> -        gi2c->rinfo.recover_bus = geni_i2c_recover_bus;
>>> -        gi2c->adap.bus_recovery_info = &gi2c->rinfo;
>>> -    }
>>> +    gi2c->rinfo.recover_bus = geni_i2c_recover_bus;
>>> +    gi2c->adap.bus_recovery_info = &gi2c->rinfo;
>>
>> I guess one more time this. Why patch 2 is adding and patch 3 is 
>> removing the change ? keep it clean way.
> 
> This is intentional. In patch 2, bus recovery is supported only in FIFO 
> mode, so we guard the registration with !gi2c->gpi_mode. Patch 3 adds 
> the corresponding bus recovery support for GPI mode, after which the 
> mode check is no longer needed and is removed.
> 

You are right, i saw that as complete logical block removal.
>>>       ret = i2c_add_adapter(&gi2c->adap);
>>>       if (ret) {
>>>
>>
>