Re: [PATCH 1/6] dt-bindings: iio: xilinx: Add Documentation for Sysmon

Michal Simek
2025-09-05T12:29:58Z

On 9/5/25 13:30, Jonathan Cameron wrote:
> On Fri, 5 Sep 2025 10:41:44 +0200
> Michal Simek <michal.simek@amd.com> wrote:
>
>> From: Salih Erim <salih.erim@amd.com>
>>
>> Add devicetree documentation for Xilinx Sysmon IP which is used for
>> internal chip monitoring on Xilinx Versal SOCs.
>>
>> Co-developed-by: Anand Ashok Dumbre <anand.ashok.dumbre@xilinx.com>
>> Signed-off-by: Anand Ashok Dumbre <anand.ashok.dumbre@xilinx.com>
>> Co-developed-by: Anish Kadamathikuttiyil Karthikeyan Pillai <anish.kadamathikuttiyil-karthikeyan-pillai@amd.com>
>> Signed-off-by: Anish Kadamathikuttiyil Karthikeyan Pillai <anish.kadamathikuttiyil-karthikeyan-pillai@amd.com>
>> Signed-off-by: Salih Erim <salih.erim@amd.com>
>> Signed-off-by: Michal Simek <michal.simek@amd.com>
>> ---
>>
>> .../bindings/iio/adc/xlnx,versal-sysmon.yaml | 235 ++++++++++++++++++
>> 1 file changed, 235 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/iio/adc/xlnx,versal-sysmon.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/iio/adc/xlnx,versal-sysmon.yaml b/Documentation/devicetree/bindings/iio/adc/xlnx,versal-sysmon.yaml
>> new file mode 100644
>> index 000000000000..a768395cade7
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/iio/adc/xlnx,versal-sysmon.yaml
>> @@ -0,0 +1,235 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/iio/adc/xlnx,versal-sysmon.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Xilinx Versal Sysmon
>> +
>> +maintainers:
>> + - Salih Erim <salih.erim@amd.com>
>> +
>> +description:
>> + The Xilinx Sysmon provides on-chip monitoring and control for the supply
>> + voltages and temperatures across the chip. Since there are only 160 supply
>> + voltage registers and 184 measurement points, there is no constant mapping
>> + of supply voltage registers and the measurement points. User has to select
>> + the voltages to monitor in design tool. Depending on the selection, a voltage
>> + supply gets mapped to one of the supply registers. So, this mapping information
>> + is provided via description which contain the information of name of
>> + the supply enabled and the supply register it maps to.
>> +
>> +properties:
>> + compatible:
>> + items:
>> + - const: xlnx,versal-sysmon
>> +
>> + reg:
>> + maxItems: 1
>> + description: Sysmon Registers.
>> +
>> + interrupts:
>> + maxItems: 1
>> + description: Interrupt line for Sysmon.
>> +
>> + '#address-cells':
>> + const: 1
>> +
>> + '#size-cells':
>> + const: 0
>> +
>> + '#io-channel-cells':
>> + const: 0
>> +
>> + xlnx,hbm:
>> + type: boolean
>> + description:
>> + Exists if node refers to a HBM (High Bandwidth Memory) SLR (Super Logic Region).
>> +
>> + xlnx,nodeid:
>> + $ref: /schemas/types.yaml#/definitions/uint32
>> + description:
>> + PLM specified sysmon node id.
>> +
>> + xlnx,numaiechannels:
>> + $ref: /schemas/types.yaml#/definitions/uint32
>> + minimum: 1
>> + maximum: 64
>> + description:
>> + Total number of sysmon satellites close to AI Engine exposed as channels.
>
> Feels like some use - would make this easier to parse. xlnx,num-aie-channels.
> Similar to the next one. How is this related to the number of child nodes?

it is number of childs below. They can be calculated to get this number.

>
>
>> +
>> + xlnx,numchannels:
>> + $ref: /schemas/types.yaml#/definitions/uint32
>> + minimum: 1
>> + maximum: 160
>> + description:
>> + Number of supply channels enabled in the design.
>
> Given you have subnodes called supplyxxx why is a count
> of those needed or is this not counting those?

possible.

>
>> +
>> +patternProperties:
>> + "^supply@([0-9]{1,2}|1[0-5][0-9])$":
>> + type: object
>> + description:
>> + Represents the supplies configured in the design.
>> +
>> + properties:
>> + reg:
>> + $ref: /schemas/types.yaml#/definitions/uint32
>> + minimum: 0
>> + maximum: 159
>> + description:
>> + The supply number associated with the voltage.
>> +
>> + xlnx,name:
>> + $ref: /schemas/types.yaml#/definitions/string
>> + description:
>> + Name of the supply enabled
>
> Would the generic property "label" be useable here?

label should be fine.

>
>> +
>> + xlnx,bipolar:
>> + $ref: /schemas/types.yaml#/definitions/flag
>> + description:
>> + If the supply has a bipolar type and the output will be signed.
>
> This is very generic. We have it described for ADC channels already in
> bindings/iio/adc/adc.yaml. Why can't we use that here?

no issue with it.
And likely
Documentation/devicetree/bindings/iio/adc/xlnx,zynqmp-ams.yaml
should deprecated it and start to use new one.

> That binding does rely on matching against 'channel' for node names though.
> Where a 'type of channel' has been relevant IIRC we've always added
> a separate property rather than using the child node name.

Is this related to supply/temp channel name?

I think one issue with the binding is that current schema allows to define
supply@1 and also temp@1
but both of them have reg = <1> which is not allowed (duplicate unit-address).

Salih: What does this reg value means? Is it physical address where that sensor
is placed?

>
>> +
>> + required:
>> + - reg
>> + - xlnx,name
>> +
>> + additionalProperties: false
>> +
>> + "^temp@([1-9]|[1-5][0-9]|6[0-4])$":
>> + type: object
>> + description:
>> + Represents the sysmon temperature satellites.
>> +
>> + properties:
>> + reg:
>> + minimum: 1
>> + maximum: 64
>> + description:
>> + The sysmon temperature satellite number.
>> +
>> + xlnx,aie-temp:
>> + $ref: /schemas/types.yaml#/definitions/flag
>> + description:
>> + If present it indicates the temperature satellite is in
>> + close proximity with AI Engine
>
> This one seems unusual. I guess it makes a configuration difference
> of some type. I'll look at the code to see if that answers the question.

it is supposed to be identify location of this sensor.

>
>> +
>> + xlnx,name:
>> + $ref: /schemas/types.yaml#/definitions/string
>> + description:
>> + Name of temperature satellite exposed
>
> As above. label tends to get used for things like this.

no issue with this.
>> +
>> + required:
>> + - reg
>> + - xlnx,name
>> +
>> + additionalProperties: false
>> +
>> +required:
>> + - compatible
>> + - reg
>> + - xlnx,numchannels
>> +
>> +additionalProperties: false
>
Thanks,
Michal