On 15/12/2023 11:33, Jie Luo wrote: >>>>>>>>> + cmn-reference-clock: >>>>>>>>> + oneOf: >>>>>>>>> + - items: >>>>>>>>> + - enum: >>>>>>>>> + - 0 # CMN PLL reference internal 48MHZ >>>>>>>>> + - 1 # CMN PLL reference external 25MHZ >>>>>>>>> + - 2 # CMN PLL reference external 31250KHZ >>>>>>>>> + - 3 # CMN PLL reference external 40MHZ >>>>>>>>> + - 4 # CMN PLL reference external 48MHZ >>>>>>>>> + - 5 # CMN PLL reference external 50MHZ >>>>>>>>> + - 6 # CMN PLL reference internal 96MHZ >>>>>>>> >>>>>>>> Why is this not represented by an element of the clocks property? >>>>>>> >>>>>>> This property is for the reference clock source selection of CMN PLL, >>>>>>> CMN PLL generates the different clock rates for the different Ethernet >>>>>>> blocks, this CMN PLL configuration is not located in the GCC, so the >>>>>>> clock framework can't be used, which is the general hardware register >>>>>>> instead of RCG register for GCC. >>>>>> >>>>>> I don't see how the clock being provided by the "GCC" (whatever that is) >>>>>> or by some other clock controller or fixed clock makes a difference. >>>>>> Why can't the other clock provider be represented in the devicetree? >>>>>> >>>>> >>>>> cmn-reference-clock is for selecting the reference clock source for the >>>>> whole Ethernet block, which is just the standalone configure register. >>>> >>>> Sure, you are aware though that all clocks are just configure registers? >>>> >>>> Which clocks are these mentioned in the property? From where do they come? >>>> >>>> Anyway, property is in existing form is not correct - this is not a >>>> generic property. >>>> >>> >>> This property cmn-reference-clock is just the hardware register >>> configuration, since the different IPQ platform needs to select >>> the different reference clock source for the CMN PLL block that >>> provides the various clock outputs to the all kinds of Ethernet >>> devices, which is not from GCC provider. >> >> AGAIN: where do the clocks come from? Which device generates them? > > Oh, OK, the reference clock is from wifi that provides 48MHZ to > Ethernet block. Then WiFi should be providing you the clock and this device should be clock consumer, right? Best regards, Krzysztof
