Re: [PATCH v1 01/13] dt-bindings: soc: starfive: Add StarFive JHB100 syscon modules

Changhuang Liang
2026-04-07T07:34:29Z

Hi, Krzysztof

Thanks for the review.

> On Thu, Apr 02, 2026 at 10:49:33PM -0700, Changhuang Liang wrote:
> > Add documentation to describe StarFive JHB100 SoC System Controller
> > Registers.
> >
> > Signed-off-by: Changhuang Liang <changhuang.liang@starfivetech.com>
> > ---
> > .../soc/starfive/starfive,jhb100-syscon.yaml | 140
> ++++++++++++++++++
> > MAINTAINERS | 5 +
> > 2 files changed, 145 insertions(+)
> > create mode 100644
> > Documentation/devicetree/bindings/soc/starfive/starfive,jhb100-syscon.
> > yaml
> >
> > diff --git
> > a/Documentation/devicetree/bindings/soc/starfive/starfive,jhb100-sysco
> > n.yaml
> > b/Documentation/devicetree/bindings/soc/starfive/starfive,jhb100-sysco
> > n.yaml
> > new file mode 100644
> > index 000000000000..c0e1f6f68fa2
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/soc/starfive/starfive,jhb100-s
> > +++ yscon.yaml
> > @@ -0,0 +1,140 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) %YAML 1.2
> > +---
> > +$id:
> > +http://devicetree.org/schemas/soc/starfive/starfive,jhb100-syscon.yam
> > +l#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: StarFive JHB100 SoC system controller
> > +
> > +maintainers:
> > + - Kevin Xie <kevin.xie@starfivetech.com>
> > + - Changhuang Liang <changhuang.liang@starfivetech.com>
> > +
> > +description:
> > + The StarFive JHB100 SoC system controller provides register
> > +information such
> > + as offset, mask and shift to configure related modules such as PLL and
> PCIe.
>
> How a MMIO based device can provide a MMIO information? What exactly
> does it provide? Register where the value is the offset of other register?

For example:
in per1 syscon:
offset 0x4 is the register configuration for implementing eMMC extended functions,
and offsets 0x40–0x4c are used for PLL7 register configuration.

In sys0 syscon:
offsets 0x0–0x2c are used for register configuration of PLL2 to PLL5,
and offset 0x38 is used for register configuration to provide the product ID.

> > +
> > +properties:
> > + compatible:
> > + oneOf:
> > + - items:
> > + - enum:
> > + - starfive,jhb100-pcierp-syscon
> > + - starfive,jhb100-per0-syscon
> > + - starfive,jhb100-per1-syscon
> > + - starfive,jhb100-sys0-syscon
> > + - const: syscon
> > + - const: simple-mfd
> > + - items:
> > + - enum:
> > + - starfive,jhb100-b2h-syscon
> > + - starfive,jhb100-gpu-syscon
> > + - starfive,jhb100-h2b-syscon
> > + - starfive,jhb100-host-syscon
> > + - starfive,jhb100-husb-syscon
> > + - starfive,jhb100-husbcmn-syscon
> > + - starfive,jhb100-husbd-syscon
> > + - starfive,jhb100-npu-syscon
> > + - starfive,jhb100-pcieep-ecsr-syscon
> > + - starfive,jhb100-pcierp-ecsr-syscon
> > + - starfive,jhb100-per2-syscon
> > + - starfive,jhb100-per3-syscon
>
> Hm? per2 as starfive,jhb100-per2crg is a separate device, so how can it be
> also a syscon?

The JHB100 SoC is divided into many domains, including the per2 domain.
Each domain has its own CRG and syscon.

Best Regards,
Changhuang