On Tue, Oct 01, 2024 at 02:28:52PM +0800, Tyrone Ting wrote: > From: Tyrone Ting <kfting@xxxxxxxxxxx> > > The users want to connect a lot of masters on the same bus. > This timeout is used to determine the time it takes to take bus ownership. > The transactions are very long, so waiting 35ms is not enough. > > Increase the timeout and treat it as the total timeout, including retries. > The total timeout is 2 seconds now. > > The i2c core layer will have chances to retry to call the i2c driver > transfer function if the i2c driver reports that the bus is busy and > returns EAGAIN. -EAGAIN ... > + /* > + * Adaptive TimeOut: estimated time in usec + 100% margin: > + * 2: double the timeout for clock stretching case > + * 9: bits per transaction (including the ack/nack) > + */ > + timeout_usec = (2 * 9 * USEC_PER_SEC / bus->bus_freq) * (2 + nread + nwrite); Side note (as I see it was in the original code), from physics point of view the USEC_PER_SEC here should be simply MICRO (as 1/Hz == s, and here it will be read as s^2 in the result), but if one finds the current more understandable, okay then. -- With Best Regards, Andy Shevchenko
