Re: [PATCH v2 1/5] dt-bindings: bus: add Broadcom BCM6362 WLAN AXI backplane

[Alessio Ferri <alessio.ferri@mythread.it>]

On Mon, 12 Oct 2026 20:13:46 +0100
Conor Dooley <conor@kernel.org> wrote:

> On Mon, Oct 12, 2026 at 12:45:25AM +0200, Alessio Ferri wrote:
> > The BCM6362 integrates a WLAN macro on its own AXI backplane.
> > Unlike the backplanes covered by brcm,bus-axi, its cores have no
> > wrappers: clock gating and reset are driven through a separate
> > WLAN control register block, and the macro needs a clock, two
> > resets and the WLAN pads power domain before the backplane can be
> > accessed. The backplane registers are big-endian.
> > 
> > Add a binding describing the ChipCommon and WLAN control register
> > blocks, the clock, resets and power domain, and the interrupt-map
> > used to route core interrupts, following the brcm,bus-axi
> > convention.
> > 
> > Assisted-by: LLM
> > Signed-off-by: Alessio Ferri <alessio.ferri@mythread.it>
> > ---
> >  .../bindings/bus/brcm,bcm6362-wlan-bus-axi.yaml    | 100
> > +++++++++++++++++++++ 1 file changed, 100 insertions(+)
> > 
> > diff --git
> > a/Documentation/devicetree/bindings/bus/brcm,bcm6362-wlan-bus-axi.yaml
> > b/Documentation/devicetree/bindings/bus/brcm,bcm6362-wlan-bus-axi.yaml
> > new file mode 100644 index 000000000000..183de28fd032 --- /dev/null
> > +++
> > b/Documentation/devicetree/bindings/bus/brcm,bcm6362-wlan-bus-axi.yaml
> > @@ -0,0 +1,100 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR
> > BSD-2-Clause) +%YAML 1.2
> > +---
> > +$id:
> > http://devicetree.org/schemas/bus/brcm,bcm6362-wlan-bus-axi.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml# +
> > +title: Broadcom BCM6362 integrated WLAN AXI backplane
> > +
> > +maintainers:
> > +  - Alessio Ferri <alessio.ferri@mythread.it>
> > +
> > +description: |
> > +  The BCM6362 integrates a WLAN macro on a dedicated AXI backplane
> > +  (bcma), whose cores are discovered at runtime from the backplane
> > +  EROM.
> > +
> > +  The cores have no DMP wrappers: clock gating and reset of the
> > +  ChipCommon and 802.11 cores are controlled through a separate
> > WLAN
> > +  control register block. The backplane registers are big-endian.
> > +
> > +  Interrupts of the cores are described with an interrupt-map,
> > keyed
> > +  by the core base address and the core interrupt index, as for
> > +  brcm,bus-axi.
> > +
> > +properties:
> > +  compatible:
> > +    const: brcm,bcm6362-wlan-bus-axi
> > +
> > +  reg:
> > +    items:
> > +      - description: ChipCommon core registers
> > +      - description: WLAN control registers
> > +
> > +  reg-names:
> > +    items:
> > +      - const: chipcommon
> > +      - const: wlan-ctrl
> > +
> > +  clocks:
> > +    maxItems: 1
> > +
> > +  resets:
> > +    items:
> > +      - description: WLAN macro reset
> > +      - description: WLAN UBUS interface reset
> > +
> > +  reset-names:
> > +    items:
> > +      - const: wlan
> > +      - const: wlan-ubus
> > +
> > +  power-domains:
> > +    maxItems: 1
> > +
> > +  "#address-cells":
> > +    const: 1
> > +
> > +  "#interrupt-cells":
> > +    const: 1
> > +
> > +  interrupt-map-mask: true
> > +
> > +  interrupt-map: true  
> 
> I'd like to see some constraints on these, particularly since there's
> a very high chance the mask is fixed and the map has a fixed number of
> elements.

Yes, you're right, i'll add them in the next batch. 

> 
> I'd also like to see what the child nodes on this bus look like. Do
> you have some dts examples?
> 

the children are enumerated dynamically by bcma itself, so i don't
expect any. I know that a childless bus is suspect, but bcma seems to
work this way.

> Thanks,
> Conor.
> 
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - reg-names
> > +  - clocks
> > +  - resets
> > +  - reset-names
> > +  - power-domains
> > +  - "#address-cells"
> > +  - "#interrupt-cells"
> > +  - interrupt-map-mask
> > +  - interrupt-map
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +    #include <dt-bindings/clock/bcm6362-clock.h>
> > +    #include <dt-bindings/reset/bcm6362-reset.h>
> > +    #include <dt-bindings/soc/bcm6362-pm.h>
> > +
> > +    bus@10004000 {
> > +        compatible = "brcm,bcm6362-wlan-bus-axi";
> > +        reg = <0x10004000 0x1000>, <0x10007000 0x100>;
> > +        reg-names = "chipcommon", "wlan-ctrl";
> > +
> > +        #address-cells = <1>;
> > +        clocks = <&periph_clk BCM6362_CLK_WLAN_OCP>;
> > +        #interrupt-cells = <1>;
> > +        interrupt-map = <0x00005000 0 &periph_intc 7>;
> > +        interrupt-map-mask = <0x000fffff 0xffff>;
> > +        power-domains = <&periph_pwr
> > BCM6362_POWER_DOMAIN_WLAN_PADS>;
> > +        resets = <&periph_rst BCM6362_RST_WLAN_SHIM>,
> > +                 <&periph_rst BCM6362_RST_WLAN_UBUS>;
> > +        reset-names = "wlan", "wlan-ubus";
> > +    };
> > 
> > -- 
> > 2.56.0
> >   

Thanks for the inputs,
Alessio