Hi Heiko, On 2016年01月02日 10:34, Xing Zheng wrote: > 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 <he...@sntech.de> 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>
I tested your patch just now, it seems to work well. I will do more tests. Thank you. :-) -- To unsubscribe from this list: send the line "unsubscribe linux-clk" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
