On 15/12/2023 11:40, Jie Luo wrote: > > > On 12/15/2023 6:37 PM, Krzysztof Kozlowski wrote: >> 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? > > Yes, wifi provides 48MHz clock to CMM PLL block, there is no GCC > for this 48MHZ clock output, it is the hardware PIN connection. All clocks are some hardware pin connections. Best regards, Krzysztof
