On 18/03/2025 12:31, Christian Marangi wrote: > On Sun, Mar 16, 2025 at 06:01:02PM +0100, Krzysztof Kozlowski wrote: >> On 11/03/2025 19:51, Christian Marangi wrote: >>>> >>>>> + $ref: /schemas/types.yaml#/definitions/uint32 >>>>> + enum: [0, 1] >>>> >>>> I don't understand why do you need index property here (which are >>>> usually not allowed). >>>> >>> >>> Eh... As said in the description this is really to differentiate the 2 >>> different physical port... >>> >>> Each port have a dedicated oscillator for calibration and these >>> calibration are identified by an offset (all placed one after another in >>> a separate register space). >> >> So different oscillators? Then describe the oscillator and its differences. >> >> Different programing model? Different compatible. >> >> Other difference? Depending what is the difference. >> >> But there is no such thing as "different port ID" based on your >> description above. You just claimed that they are different, but you do >> not put that difference to hardware description. Instead you encode that >> difference in the drivers and it should be opposite. The DTS, so the >> hardware description, should tell you the difference. And I am sorry, >> but in 99% of cases "I am the first phy" and "I am the second" is not >> the actual difference we are interested in. >> > > Ok to make it as clear as possible. (hope I don't contraddict with the > previous statement) (actually yes the "separate register space statement > was wrong and sorry for the confusion") > > - 2 USB port > - USB 2.0 needs to be calibrated with an oscillator > - Each USB port have his own dedicated oscillator somewhere in the HW > - Each USB port have at the same offset a register to SELECT the > oscillator. This register refer to the same oscillator selection in > the HW. > > Example: > reg 0x1fac0100 MASK 27:26 can be set to source out of oscillator 0,1,2 > reg 0x1fae0100 MASK 27:26 can be set to source out of oscillator 0,1,2 So that's your difference between devices - you choose the oscillator. > > Both register refer to the same oscillators in hardware (hence each > port should select the correct one) > Selecting oscillator 0 for both USB port is problematic. > > With this in mind is it ok if I describe this with something like > > airoha,usb2-monitor-clk-sel = <AIROHA_USB2_MONCLK_SEL0>; > > and some dt-bindings include > > #define AIROHA_USB2_MONCLK_SEL0 0 > #define AIROHA_USB2_MONCLK_SEL1 1 > #define AIROHA_USB2_MONCLK_SEL2 2 > #define AIROHA_USB2_MONCLK_SEL3 3 > > Or an enum of string like "osc0", "osc1", "osc2"...? Both are fine. Best regards, Krzysztof
