On Thu, Nov 28, 2013 at 09:02:58AM +0100, boris brezillon wrote: > On 27/11/2013 19:10, Mike Turquette wrote: > >Quoting boris brezillon (2013-11-27 09:19:08) > >>>On Wed, Nov 27, 2013 at 01:44:45PM +0100, Boris BREZILLON wrote: ... > >>>I would also prefer to see an unknown accuracy be -1. > >>I decided to keep 0 as a default value for unimplemented recalc_accuracy > >>(or unspecified fixed accuracy) to keep existing implementation coherent. > >> > >>0 means the clk is perfect, and I thought it would be easier to handle a > >>perfect clk (even if this is not really the case) than handling an error > >>case. > >> > >>Another aspect is the propagation of the clk accuracy accross the clk tree. > >>Returning -1 in the middle of the clk chain will drop the previous clk > >>accuracy > >>calculation. > >> > >>Anyway, I can change this if you think this is more appropriate. > >What about the absence of the property? > >Instead of requiring a -1 value > >can we simply detect that the property does not exist? This is nicer for > >backwards compatibility with existing DTS. > > I already handle the absence of the clock-accuracy property. > In this case the clock is considered perfect (accuracy = 0 ppb). Yeah, in order to calculate the theoretical accuracy of a leaf node, a missing accuracy in the middle of the chain really derails things. Since my previous concern (modelling the real accuracy of the clocks) is not an issue here, I think assuming the absent accuracy is 0 is fine. Especially since all Boris is trying to do is avoid the RC clocks. thx, Jason. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
