On 01/04/2022 09:55, Heiko Stübner wrote: > Hi Stephen, > > Am Freitag, 1. April 2022, 00:51:32 CEST schrieb Stephen Boyd: >> Quoting Johan Jonker (2022-03-29 04:13:22) >>> diff --git a/Documentation/devicetree/bindings/clock/rockchip,rk3188-cru.yaml b/Documentation/devicetree/bindings/clock/rockchip,rk3188-cru.yaml >>> new file mode 100644 >>> index 000000000..ddd7e46af >>> --- /dev/null >>> +++ b/Documentation/devicetree/bindings/clock/rockchip,rk3188-cru.yaml >>> @@ -0,0 +1,78 @@ >>> +# SPDX-License-Identifier: GPL-2.0 >>> +%YAML 1.2 >>> +--- >>> +$id: http://devicetree.org/schemas/clock/rockchip,rk3188-cru.yaml# >>> +$schema: http://devicetree.org/meta-schemas/core.yaml# >>> + >>> +title: Rockchip RK3188/RK3066 Clock and Reset Unit (CRU) >>> + >>> +maintainers: >>> + - Elaine Zhang <zhangqing@xxxxxxxxxxxxxx> >>> + - Heiko Stuebner <heiko@xxxxxxxxx> >>> + >>> +description: | >>> + The RK3188/RK3066 clock controller generates and supplies clocks to various >>> + controllers within the SoC and also implements a reset controller for SoC >>> + peripherals. >>> + Each clock is assigned an identifier and client nodes can use this identifier >>> + to specify the clock which they consume. All available clocks are defined as >>> + preprocessor macros in the dt-bindings/clock/rk3188-cru.h and >>> + dt-bindings/clock/rk3066-cru.h headers and can be used in device tree sources. >>> + Similar macros exist for the reset sources in these files. >>> + There are several clocks that are generated outside the SoC. It is expected >>> + that they are defined using standard clock bindings with following >>> + clock-output-names: >>> + - "xin24m" - crystal input - required >>> + - "xin32k" - RTC clock - optional >>> + - "xin27m" - 27mhz crystal input on RK3066 - optional >>> + - "ext_hsadc" - external HSADC clock - optional >>> + - "ext_cif0" - external camera clock - optional >>> + - "ext_rmii" - external RMII clock - optional >>> + - "ext_jtag" - external JTAG clock - optional >> >> I'd expect all these clks here to be inputs to this node. > > The optional clocks are all part of a circular dependency. > > So for example xin32k normally is generated by the pmic and fed > back into the system, so to get xin32k, we need the pmic to probe, > which needs i2c, which in turn already needs the clock controller. Are you sure that xin32k (RTC) clock should be input to the clock controller? I would expect it is the input to the SoC RTC block, so there is no circular dependency. Best regards, Krzysztof
