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| 1 | +* Renesas R-Car USB 2.0 clock selector |
| 2 | + |
| 3 | +This file provides information on what the device node for the R-Car USB 2.0 |
| 4 | +clock selector. |
| 5 | + |
| 6 | +If you connect an external clock to the USB_EXTAL pin only, you should set |
| 7 | +the clock rate to "usb_extal" node only. |
| 8 | +If you connect an oscillator to both the USB_XTAL and USB_EXTAL, this module |
| 9 | +is not needed because this is default setting. (Of course, you can set the |
| 10 | +clock rates to both "usb_extal" and "usb_xtal" nodes. |
| 11 | + |
| 12 | +Case 1: An external clock connects to R-Car SoC |
| 13 | + +----------+ +--- R-Car ---------------------+ |
| 14 | + |External |---|USB_EXTAL ---> all usb channels| |
| 15 | + |clock | |USB_XTAL | |
| 16 | + +----------+ +-------------------------------+ |
| 17 | +In this case, we need this driver with "usb_extal" clock. |
| 18 | + |
| 19 | +Case 2: An oscillator connects to R-Car SoC |
| 20 | + +----------+ +--- R-Car ---------------------+ |
| 21 | + |Oscillator|---|USB_EXTAL -+-> all usb channels| |
| 22 | + | |---|USB_XTAL --+ | |
| 23 | + +----------+ +-------------------------------+ |
| 24 | +In this case, we don't need this selector. |
| 25 | + |
| 26 | +Required properties: |
| 27 | +- compatible: "renesas,r8a7795-rcar-usb2-clock-sel" if the device is a part of |
| 28 | + an R8A7795 SoC. |
| 29 | + "renesas,r8a7796-rcar-usb2-clock-sel" if the device if a part of |
| 30 | + an R8A7796 SoC. |
| 31 | + "renesas,rcar-gen3-usb2-clock-sel" for a generic R-Car Gen3 |
| 32 | + compatible device. |
| 33 | + |
| 34 | + When compatible with the generic version, nodes must list the |
| 35 | + SoC-specific version corresponding to the platform first |
| 36 | + followed by the generic version. |
| 37 | + |
| 38 | +- reg: offset and length of the USB 2.0 clock selector register block. |
| 39 | +- clocks: A list of phandles and specifier pairs. |
| 40 | +- clock-names: Name of the clocks. |
| 41 | + - The functional clock must be "ehci_ohci" |
| 42 | + - The USB_EXTAL clock pin must be "usb_extal" |
| 43 | + - The USB_XTAL clock pin must be "usb_xtal" |
| 44 | +- #clock-cells: Must be 0 |
| 45 | + |
| 46 | +Example (R-Car H3): |
| 47 | + |
| 48 | + usb2_clksel: clock-controller@e6590630 { |
| 49 | + compatible = "renesas,r8a77950-rcar-usb2-clock-sel", |
| 50 | + "renesas,rcar-gen3-usb2-clock-sel"; |
| 51 | + reg = <0 0xe6590630 0 0x02>; |
| 52 | + clocks = <&cpg CPG_MOD 703>, <&usb_extal>, <&usb_xtal>; |
| 53 | + clock-names = "ehci_ohci", "usb_extal", "usb_xtal"; |
| 54 | + #clock-cells = <0>; |
| 55 | + }; |
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