On 1/21/26 16:21, Rob Herring wrote:
> On Wed, Jan 21, 2026 at 01:34:37PM +0100, Gatien Chevallier wrote:
>> Document the stm32 debug bus. The debug bus is responsible for
>> checking the debug sub-system accessibility before probing any related
>> drivers.
>>
>> Signed-off-by: Gatien Chevallier <gatien.chevallier@foss.st.com>
>> ---
>> .../bindings/bus/st,stm32mp131-dbg-bus.yaml | 79 ++++++++++++++++++++++
>> 1 file changed, 79 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/bus/st,stm32mp131-dbg-bus.yaml b/Documentation/devicetree/bindings/bus/st,stm32mp131-dbg-bus.yaml
>> new file mode 100644
>> index 000000000000..2db35e41e76c
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/bus/st,stm32mp131-dbg-bus.yaml
>> @@ -0,0 +1,79 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/bus/st,stm32mp131-dbg-bus.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: STM32 Coresight bus
>> +
>> +maintainers:
>> + - Gatien Chevallier <gatien.chevallier@foss.st.com>
>> +
>> +description:
>> + The STM32 debug bus is in charge of checking the debug configuration
>> + of the platform before probing the peripheral drivers that rely on the debug
>> + domain.
>> +
>> +properties:
>> + compatible:
>> + items:
>> + - enum:
>> + - st,stm32mp131-dbg-bus
>> + - st,stm32mp151-dbg-bus
>> +
>> + "#address-cells":
>> + const: 1
>> +
>> + "#size-cells":
>> + const: 1
>> +
>> + ranges: true
>> +
>> + reg:
>> + maxItems: 1
>> +
>> + "#access-controller-cells":
>> + const: 1
>> + description:
>> + Contains the debug profile necessary to access the peripheral.
>> +
>> +patternProperties:
>> + "^.*@[0-9a-f]+$":
>> + description: Debug related peripherals
>> + type: object
>> +
>> + additionalProperties: true
>> +
>> + required:
>> + - access-controllers
>> +
>> +required:
>> + - "#access-controller-cells"
>> + - "#address-cells"
>> + - "#size-cells"
>> + - compatible
>> + - ranges
>> + - reg
>> +
>> +additionalProperties: false
>> +
>> +examples:
>> + - |
>> + #include <dt-bindings/clock/stm32mp1-clks.h>
>> +
>> + dbg_bus: bus@50080000 {
>> + compatible = "st,stm32mp131-dbg-bus";
>> + reg = <0x50080000 0x3f80000>;
>
> That's a lot of registers... Yet the bus driver doesn't access any.
> Looks to me like this belongs in ranges instead if there aren't any bus
> registers. Or its size should be just the registers and then the whole
> region size goes in ranges.
>
Hello Rob,
Understandable comment. I'll switch to defining the range in the
ranges property in the V3.
Thank you,
Gatien
>> + #address-cells = <1>;
>> + #size-cells = <1>;
>> + #access-controller-cells = <1>;
>> + ranges;
>> +
>> + cs_cti_trace: cti@50094000 {
>> + compatible = "arm,coresight-cti", "arm,primecell";
>> + reg = <0x50094000 0x1000>;
>> + clocks = <&rcc CK_DBG>;
>> + clock-names = "apb_pclk";
>> + access-controllers = <&dbg_bus 0>;
>> + };
>> + };
>>
>> --
>> 2.43.0
>>