Abraham vd Merwe wrote: > Hi Mark! > > >>>>2) There is 3 fields in the i2c_algo_bit_data structure for timing: udelay, >>>>mdelay, timeout. What should I make this? I've made them 80, 80, 100 >>>>respectively (stolen from Russell King's acorn RTC driver), but I'm not sure >>>>if this is the best selection... >>> >>> >>>Humm... I'll have to punt this to either Mark or Frodo. >>> >>> >> >>the numbers are half-clock-cycle times in microseconds. >>So 80 means a clock of approx. 6 kHz which is really slow. >>Don't know what the difference between udelay and mdelay is, >>have always seen them the same. > > > Why is this clock fixed? Surely, slow chips on the bus will delay the bus as > long as necessary? > well, you have to start somewhere. Slaves can stretch the clock lower, if they support it (don't count on it). But you can't go any faster than the rate you set in algo-bit. see the algo-bit code and you'll see how it works.
