Re: [PATCH v2] i2c: qcom-geni: Add dynamic transfer timeout based on transfer length and frequency

[Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>]

On 7/5/26 3:57 PM, Aniket Randive wrote:
> The driver uses a static XFER_TIMEOUT of HZ (1 second) for all transfers
> regardless of message length or bus frequency, causing unnecessary
> delays on error paths.
> 
> Compute the timeout dynamically from message length and bus frequency
> with a 10x safety margin over the theoretical wire time and a 300ms
> floor. For GPI multi-descriptor transfers, use the maximum message
> length across all queued messages as the per-completion timeout.

What's the reason for a 0.3 s floor?

Why a 10x safety margin specifically?

[...]

> +static unsigned long geni_i2c_xfer_timeout(struct geni_i2c_dev *gi2c, size_t len)
> +{
> +	size_t bit_cnt = len * 9;
> +	size_t bit_usec = (bit_cnt * USEC_PER_SEC) / gi2c->clk_freq_out;

mult_frac()

Konrad