Dear Ryan,
On Mon, 2011-03-07 at 11:02 +1300, Ryan Mallon wrote:
- sdiv = 4;
- if (div > (256 + 512) / 2) {
lrdiv = 128;- } else {
lrdiv = 64;if (div < (128 + 256) / 2)sdiv = 2;- }
I don't understand where the magic numbers above come from? Does it work correctly for all rates? I think a comment is needed to explain how this works.
The Magic is simply centers between divisors. The loop produced only 3 variants of divisors. So do this code. But it's simpler and it prefers LRDIV = 64. I do not know what do you mean by all rates, with fixed MCLK there is no way to produce all the rates. With variable MCLK I'm having full 8000-192000 range now.
An alternative would be to keep the existing loop form, but try and find the closest match rather than an exact match. Something like this (untested):
This is huge comparing to 2 ifs... But the main task of keeping LRCLK=64 where possible still can be achieved if we swap to lines:
for (sdiv = 2; sdiv <= 4; sdiv += 2) { for (lrdiv = 64; lrdiv <= 128; lrdiv <<= 1) {
But I'm sure code proposed by me should work just like previous variant for you. Could you try it with your configuration please?