Re: [PATCH v6 2/2] i2c: qcom-geni: Add dynamic transfer timeout based on transfer length and frequency

[Aniket RANDIVE <aniket.randive@oss.qualcomm.com>]

On 7/22/2026 10:56 AM, Mukesh Savaliya wrote:
> 
> 
> On 7/20/2026 5:11 PM, Aniket Randive wrote:
> [...]
> 
>> ---
>>   drivers/i2c/busses/i2c-qcom-geni.c | 37 ++++++++++++++++++++++++++++ 
>> +--------
>>   1 file changed, 29 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/ 
>> i2c-qcom-geni.c
>> index 96dbf04138be..d6fab3aa8468 100644
>> --- a/drivers/i2c/busses/i2c-qcom-geni.c
>> +++ b/drivers/i2c/busses/i2c-qcom-geni.c
>> @@ -74,9 +74,14 @@ enum geni_i2c_err_code {
>>   #define PACKING_BYTES_PW    4
>>   #define ABORT_TIMEOUT        HZ
>> -#define XFER_TIMEOUT        HZ
>>   #define RST_TIMEOUT        HZ
>> +/* 9 bits per byte (8 data + 1 ACK), 10x safety margin */
>> +#define I2C_TIMEOUT_SAFETY_COEFFICIENT    10
>> +
>> +/* 300ms floor: budget for clock stretching; slave may hold SCL low 
>> indefinitely */
>> +#define I2C_TIMEOUT_MIN_USEC        300000
>> +
> Let other expert suggest if pass from DTSI or hardcode here. because 
> this let all other controller drivers to make change. I request to 
> conclude on discussion, i kept my point in earlier patch.

Sure, let's wait for comments from other reviewers (Wolfram, Dmitry, 
Andi) before concluding the discussion.

I have already shared my concerns in the previous thread regarding 
keeping this policy in the core versus allowing controller-specific 
configuration.

Thanks,
Aniket

>>   struct geni_i2c_desc {
>>       bool no_dma_support;
>>       unsigned int tx_fifo_depth;
>> @@ -471,7 +476,9 @@ static int geni_i2c_rx_one_msg(struct geni_i2c_dev 
>> *gi2c, struct i2c_msg *msg,
>>       }
>>       cur = gi2c->cur;
>> -    time_left = wait_for_completion_timeout(&gi2c->done, XFER_TIMEOUT);
>> +    i2c_update_timeout(&gi2c->adap, gi2c->clk_freq_out, len,
>> +               I2C_TIMEOUT_SAFETY_COEFFICIENT, I2C_TIMEOUT_MIN_USEC);
>> +    time_left = wait_for_completion_timeout(&gi2c->done, gi2c- 
>> >adap.timeout);
>>       if (!time_left)
>>           geni_i2c_abort_xfer(gi2c);
>> @@ -513,7 +520,9 @@ static int geni_i2c_tx_one_msg(struct geni_i2c_dev 
>> *gi2c, struct i2c_msg *msg,
>>           writel_relaxed(1, se->base + SE_GENI_TX_WATERMARK_REG);
>>       cur = gi2c->cur;
>> -    time_left = wait_for_completion_timeout(&gi2c->done, XFER_TIMEOUT);
>> +    i2c_update_timeout(&gi2c->adap, gi2c->clk_freq_out, len,
>> +               I2C_TIMEOUT_SAFETY_COEFFICIENT, I2C_TIMEOUT_MIN_USEC);
> Expect some discussion or conclusion from other experts if need to hard 
> code these coefficient or pass from DTSI. if core can read like existing 
> i2c_parse_fw_timings(), it would become generic to every i2c adapter 
> driver.

Agreed. This likely needs input from the maintainers before we finalize 
the approach.

Thanks,
Aniket

>> +    time_left = wait_for_completion_timeout(&gi2c->done, gi2c- 
>> >adap.timeout);
>>       if (!time_left)
>>           geni_i2c_abort_xfer(gi2c);
>>   [...]