Hi Andy: Thank you for your comments. Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> 於 2024年10月1日 週二 下午9:14寫道： > > 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. > I just check with Nuvoton members and they prefer the USEC_PER_SEC way. > -- > With Best Regards, > Andy Shevchenko > > Thank you. Regards, Tyrone
