On 13 November 2015 at 15:52, Tony Lindgren <tony@xxxxxxxxxxx> wrote: > I think this is the most recent TI git repo for dm81xx changes: > > http://arago-project.org/git/projects/?p=linux-omap3.git;a=summary Yeah, although I usually prefer to look at the linux-ipnc-rdk-dm81xx.git and linux-dvr-rdk-dm81xx.git that descend from it since they include some fixes that the last TI kernel doesn't. (However they may also include patches specific to the ipnc/dvr hardware, so some caution is needed.) Since arago can be sluggish I just mirrored all three branches on github: https://github.com/dutchanddutch/ti81xx-linux I've also fixed an obnoxious commit in the ipnc-rdk which changed all files to mode 755, since this made comparisons rather unpleasant. The PLL code looks pretty mediocre to me. In particular, they make no effort whatsoever to configure an exact ratio. It seems their algorithm uses whatever predivider was already programmed, selects the minimum postdivider that puts the DCO clock within valid range, and then approximates the dco/refclk ratio using the fractional multiplier. This works in principle, but both minimizing the DCO and (often needlessly) using the fractional multiplier seem like recipes to maximize the clock jitter. Mind you, I don't know how much jitter we're talking about here, I don't recall having seen specs about this. I also have some concerns about the correctness of the implementation. I haven't analyzed it in any detail, but repeated occurrences of expressions of the form (unsigned long long)( foo * bar ) make me doubt whether the author realizes this is utterly pointless and will, for 32-bit arguments, still perform a 32-bit multiplication. Matthijs -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
