RE: [PATCH v4 1/4] dt-bindings: clock: add ExynosAuto v920 SoC CMU bindings

["sunyeal.hong" <sunyeal.hong@samsung.com>]

Hello Rob,

> -----Original Message-----
> From: sunyeal.hong <sunyeal.hong@samsung.com>
> Sent: Thursday, July 25, 2024 10:24 AM
> To: 'Rob Herring' <robh@kernel.org>
> Cc: 'Krzysztof Kozlowski' <krzk@kernel.org>; 'Sylwester Nawrocki'
> <s.nawrocki@samsung.com>; 'Chanwoo Choi' <cw00.choi@samsung.com>; 'Alim
> Akhtar' <alim.akhtar@samsung.com>; 'Michael Turquette'
> <mturquette@baylibre.com>; 'Stephen Boyd' <sboyd@kernel.org>; 'Conor
> Dooley' <conor+dt@kernel.org>; linux-samsung-soc@vger.kernel.org; linux-
> clk@vger.kernel.org; devicetree@vger.kernel.org; linux-arm-
> kernel@lists.infradead.org; linux-kernel@vger.kernel.org
> Subject: RE: [PATCH v4 1/4] dt-bindings: clock: add ExynosAuto v920 SoC
> CMU bindings
> 
> Hello Rob,
> 
> > -----Original Message-----
> > From: Rob Herring <robh@kernel.org>
> > Sent: Wednesday, July 24, 2024 5:57 AM
> > To: Sunyeal Hong <sunyeal.hong@samsung.com>
> > Cc: Krzysztof Kozlowski <krzk@kernel.org>; Sylwester Nawrocki
> > <s.nawrocki@samsung.com>; Chanwoo Choi <cw00.choi@samsung.com>; Alim
> > Akhtar <alim.akhtar@samsung.com>; Michael Turquette
> > <mturquette@baylibre.com>; Stephen Boyd <sboyd@kernel.org>; Conor
> > Dooley <conor+dt@kernel.org>; linux-samsung-soc@vger.kernel.org;
> > linux- clk@vger.kernel.org; devicetree@vger.kernel.org; linux-arm-
> > kernel@lists.infradead.org; linux-kernel@vger.kernel.org
> > Subject: Re: [PATCH v4 1/4] dt-bindings: clock: add ExynosAuto v920
> > SoC CMU bindings
> >
> > On Tue, Jul 23, 2024 at 07:33:30AM +0900, Sunyeal Hong wrote:
> > > Add dt-schema for ExynosAuto v920 SoC clock controller.
> > > Add device tree clock binding definitions for below CMU blocks.
> > >
> > > - CMU_TOP
> > > - CMU_PERIC0
> > >
> > > Signed-off-by: Sunyeal Hong <sunyeal.hong@samsung.com>
> > > ---
> > >  .../clock/samsung,exynosautov920-clock.yaml   | 115 +++++++++++
> > >  .../clock/samsung,exynosautov920.h            | 191 ++++++++++++++++++
> > >  2 files changed, 306 insertions(+)
> > >  create mode 100644
> > > Documentation/devicetree/bindings/clock/samsung,exynosautov920-clock
> > > .y
> > > aml  create mode 100644
> > > include/dt-bindings/clock/samsung,exynosautov920.h
> > >
> > > diff --git
> > > a/Documentation/devicetree/bindings/clock/samsung,exynosautov920-clo
> > > ck
> > > .yaml
> > > b/Documentation/devicetree/bindings/clock/samsung,exynosautov920-clo
> > > ck
> > > .yaml
> > > new file mode 100644
> > > index 000000000000..90f9f17da959
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/clock/samsung,exynosautov920
> > > +++ -c
> > > +++ lock.yaml
> > > @@ -0,0 +1,115 @@
> > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) %YAML 1.2
> > > +---
> > > +$id:
> > > +https://protect2.fireeye.com/v1/url?k=9932a88e-c6ae81a4-993323c1-00
> > > +0b
> > > +abe598f7-779f1e959ac8eab9&q=1&e=539edfa4-b4e4-460a-93f4-1e6f1703094
> > > +5&
> > > +u=http%3A%2F%2Fdevicetree.org%2Fschemas%2Fclock%2Fsamsung%2Cexynosa
> > > +ut
> > > +ov920-clock.yaml%23
> > > +$schema:
> > > +https://protect2.fireeye.com/v1/url?k=4dbf6fb9-12234693-4dbee4f6-00
> > > +0b
> > > +abe598f7-363a2f64c69b9542&q=1&e=539edfa4-b4e4-460a-93f4-1e6f1703094
> > > +5&
> > > +u=http%3A%2F%2Fdevicetree.org%2Fmeta-schemas%2Fcore.yaml%23
> > > +
> > > +title: Samsung ExynosAuto v920 SoC clock controller
> > > +
> > > +maintainers:
> > > +  - Sunyeal Hong <sunyeal.hong@samsung.com>
> > > +  - Chanwoo Choi <cw00.choi@samsung.com>
> > > +  - Krzysztof Kozlowski <krzk@kernel.org>
> > > +  - Sylwester Nawrocki <s.nawrocki@samsung.com>
> > > +
> > > +description: |
> > > +  ExynosAuto v920 clock controller is comprised of several CMU
> > > +units, generating
> > > +  clocks for different domains. Those CMU units are modeled as
> > > +separate device
> > > +  tree nodes, and might depend on each other. Root clocks in that
> > > +clock tree are
> > > +  two external clocks:: OSCCLK/XTCXO (38.4 MHz) and RTCCLK/XrtcXTI
> > (32768 Hz).
> > > +  The external OSCCLK must be defined as fixed-rate clock in dts.
> > > +
> > > +  CMU_TOP is a top-level CMU, where all base clocks are prepared
> > > + using PLLs and  dividers; all other clocks of function blocks
> > > + (other
> > > + CMUs) are usually  derived from CMU_TOP.
> > > +
> > > +  Each clock is assigned an identifier and client nodes can use
> > > + this identifier  to specify the clock which they consume. All
> > > + clocks available for usage  in clock consumer nodes are defined as
> > > + preprocessor macros in  'include/dt-
> > bindings/clock/samsung,exynosautov920.h' header.
> > > +
> > > +properties:
> > > +  compatible:
> > > +    enum:
> > > +      - samsung,exynosautov920-cmu-top
> > > +      - samsung,exynosautov920-cmu-peric0
> > > +
> > > +  clocks:
> > > +    minItems: 1
> > > +    maxItems: 3
> > > +
> > > +  clock-names:
> > > +    minItems: 1
> > > +    maxItems: 3
> >
> > Move the descriptions and names here. Then in the if/then schemas just
> > set the number of items to 1 or 3 as appropriate.
> >
> > Rob
> 
> Thank you for your review. I will update by reflecting the fixes.
> 
> Thanks,
> Sunyeal Hong
> 
> 

I faced a new problem after modifying it as you reviewed.
For example, if I declare a new cmu block that uses only osclk and noc to dt, it seems that a problem occurs in check dtb.

- yaml
properties:
  compatible:
    enum:
      - samsung,exynosautov920-cmu-top
      - samsung,exynosautov920-cmu-peric0
	  - samsung,exynosautov920-cmu-misc

  clocks:
    minItems: 1
    items:
      - description: External reference clock (38.4 MHz)
      - description: Block IP clock (from CMU_TOP)
      - description: Block NOC clock (from CMU_TOP)

  clock-names:
    minItems: 1
    items:
      - const: oscclk
      - const: ip
      - const: noc

- dts
cmu_misc: clock-controller@10020000 {
	compatible = "samsung,exynosautov920-cmu-misc";
	reg = <0x10020000 0x8000>;
	#clock-cells = <1>;

	clocks = <&xtcxo>,
		 <&cmu_top DOUT_CLKCMU_MISC_NOC>;
	clock-names = "oscclk",
		      "noc";
};

In this case, can you tell me how to handle it?
And if a new clock item is added and a new cmu block uses only the clock item added and oscclk, a problem may occur.

Thanks,
Sunyeal Hong.