Hi Heiko, Thank you for your patch, I will apply and test it later. Thanks. > 在 2016年1月2日,06:10,Heiko Stübner <heiko@xxxxxxxxx> 写道: > > Hi Xing, > > Am Dienstag, 29. Dezember 2015, 10:34:09 schrieb Xing Zheng: >> On 2015年12月29日 09:59, Yakir Yang wrote: >>> On 12/28/2015 08:41 PM, Heiko Stübner wrote: >>>> Am Montag, 28. Dezember 2015, 17:03:53 schrieb Xing Zheng: >>>>> Due to referred old version TRM, there is incorrect emac clock node, >>>>> we should fix it. The SEL_21_9 is the parent of SEL_21_4. >>>>> >>>>> In the emac driver, we need to refer HCLK_MAC, and because There are >>>>> only 3PLLs (APLL/GPLL/DPLL) on the rk3036, most clock are under the >>>>> GPLL, and it is unable to provide the accurate rate for mac_ref which >>>>> need to 50MHz probability, we should let it under the APLL and are >>>>> able to set the freq which integer multiples of 50MHz, so we add these >>>>> emac node for reference. >>>> >>>> I don't really follow here. While I do understand that the emac needs >>>> 50MHz, I >>>> don't think using the APLL as source is helpful. >>>> >>>> The APLL is the main clocksource for the cpu-cores, including frequency >>>> scaling, and while it currently only lists 816MHz as sole frequency, >>>> you're >>>> pretty much guaranteed to not get your correct multiple of 50MHz from >>>> there >>>> either. And limiting the cpu to just do 600MHz to get the mac working >>>> sounds >>>> pretty bad ;-) . >>>> >>>> >>>> In the rk3036 cru-node the gpll gets set to 594MHz. Is there a >>>> special reason >>>> why it needs to be 594MHz and cannot be a round 600MHz? Because that >>>> would >>>> also provide your 50MHz-multiple nicely. >>> >>> Yes, this magic 594MHz would help to support the standard HDMI >>> resolutions, here are the math: >>> >>> 1920x1080-60Hz DCLK = 148.5MHz = 594MHz / 4 >>> 1280x720-60Hz DCLK = 74.25MHz = 594MHz / 8 >>> 720x480-60Hz DCLK = 27MHz = 594MHz / 22 >>> >>> Thanks, >>> - Yakir >> >> Thanks Yakir. >> >> Hi Heiko, >> From the above, do you have better idea for the RK3036's emac without >> ext-oscillator? > > During the last days I did play a bit with the clock framework. As I don't > have a Kylin (or any rk3036) board, I did build a test-case with pclk_cpu on > the rk3188 (which can be affected by the armclk if not reparented to the > gpll), which got sucessfully adapted to get back to (or near) the originally > requested frequency. > > So ideally you could roll back your mux/div split here and try the attached > diff. In theory it should help :-) . > As can be seen by the FIXMEs, not fully finished, but I'd like to determine if > it fixes the issue at least. > > > Heiko > <clk-keep-req-rate.diff> -- 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