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

[Aniket RANDIVE]

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);
> >   [...]