On Fri, Feb 20, 2015 at 11:13:06AM -0800, Mike Turquette wrote: > Quoting Russell King - ARM Linux (2015-02-16 03:27:24) > > On Fri, Feb 13, 2015 at 07:57:13PM +0100, Sascha Hauer wrote: > > > I agree that it's a bit odd, but I think it has to be like this. > > > Consider that you request a rate of 100Hz, but the clock can only > > > produce 99.5Hz, so due to rounding clk_round_rate() returns 99Hz. > > > Now when you request 99Hz from clk_set_rate() the 99.5Hz value > > > can't be used because it's too high. > > > > Math rounding rules normally state that anything of .5 and greater > > should be rounded up, not rounded down. So, for 99.5Hz, you really > > ought to be returning 100Hz, not 99Hz. > > > > However, you do have a point for 99.4Hz, which would be returned as > > 99Hz, and when set, it would result in something which isn't 99.4Hz. > > More practically, this again raises the issue of whether or not unsigned > long rate should be in millihertz or something other than hertz. You still get the same issue if it's millihertz. Take 10 2/3rds Hz. Is 10.666 Hz less than 10 2/3rds Hz? -- FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up according to speedtest.net. -- 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
