Am Samstag, 2. April 2022, 18:01:11 CEST schrieb Krzysztof Kozlowski: > On 02/04/2022 14:20, Johan Jonker wrote: > > > > > > On 4/2/22 14:16, Krzysztof Kozlowski wrote: > >> On 02/04/2022 13:45, Johan Jonker wrote: > >>> > >>> > >>> On 4/2/22 13:41, Krzysztof Kozlowski wrote: > >>>> 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. > >>> > >>> clk-rk3188.c: > >>> > >>> PNAME(mux_pll_p) = { "xin24m", "xin32k" }; > >> > >> Thanks, but that's not the answer whether it is an input to the clock > >> controller. It's the answer how the driver implements this. :) > > > > PX2 == rk3066 > > > > Rockchip PX2 TRM V1.0.pdf > > > > page 30 > > > > Chip Clock Architecture Diagram 1 > > I found it, thanks. That's the answer, so indeed this is an input. > > Answering partially to Heiko/Stephen, this could be still modeled in DTS > as a fixed-frequency clock going as input to the clock-controller. The > trouble with that approach is that it would actually duplicate the > definition (another one coming from PMIC). And it has the issue that the pmic doesn't necessarily has the clock enabled at boot. Also this would combat one issue by introducing a different one, as this would be modelling a clock in a way that is not reflected by hardware at all.
