RE: [PATCH v6 3/4] dt-bindings: iio: adc: Add Xilinx AMS binding documentation

[Anand Ashok Dumbre <ANANDASH@xilinx.com>]

Hi Rob,

Thank you for reviewing the patch.

My responses in line.

> -----Original Message-----
> From: Rob Herring <robh@kernel.org>
> Sent: Tuesday 13 July 2021 11:31 PM
> To: Anand Ashok Dumbre <ANANDASH@xilinx.com>
> Cc: jic23@kernel.org; lars@metafoo.de; linux-iio@vger.kernel.org; git-dev
> <git-dev@xilinx.com>; Michal Simek <michals@xilinx.com>;
> pmeerw@pmeerw.net; devicetree@vger.kernel.org; linux-
> kernel@vger.kernel.org
> Subject: Re: [PATCH v6 3/4] dt-bindings: iio: adc: Add Xilinx AMS binding
> documentation
> 
> On Thu, Jun 24, 2021 at 07:29:38PM +0100, Anand Ashok Dumbre wrote:
> > Xilinx AMS have several ADC channels that can be used for measurement
> > of different voltages and temperatures. Document the same in the
> bindings.
> >
> > Signed-off-by: Anand Ashok Dumbre <anand.ashok.dumbre@xilinx.com>
> > ---
> >  .../bindings/iio/adc/xlnx,zynqmp-ams.yaml     | 228 ++++++++++++++++++
> >  1 file changed, 228 insertions(+)
> >  create mode 100644
> > Documentation/devicetree/bindings/iio/adc/xlnx,zynqmp-ams.yaml
> >
> > diff --git
> > a/Documentation/devicetree/bindings/iio/adc/xlnx,zynqmp-ams.yaml
> > b/Documentation/devicetree/bindings/iio/adc/xlnx,zynqmp-ams.yaml
> > new file mode 100644
> > index 000000000000..a065ddd55d38
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/adc/xlnx,zynqmp-ams.yaml
> > @@ -0,0 +1,228 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) %YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/iio/adc/xlnx,zynqmp-ams.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Xilinx Zynq Ultrascale AMS controller
> > +
> > +maintainers:
> > +  - Anand Ashok Dumbre <anand.ashok.dumbre@xilinx.com>
> > +
> > +description: |
> > +  The AMS (Analog Monitoring System) includes an ADC as well as
> > +on-chip sensors
> > +  that can be used to sample external voltages and monitor on-die
> > +operating
> > +  conditions, such as temperature and supply voltage levels.
> > +  The AMS has two SYSMON blocks which are PL (Programmable Logic)
> > +SYSMON and
> > +  PS (Processing System) SYSMON.
> > +  All designs should have AMS registers, but PS and PL are optional.
> > +The
> > +  AMS controller can work with only PS, only PL and both PS and PL
> > +  configurations. Please specify registers according to your design.
> > +Devicetree
> > +  should always have AMS module property. Providing PS & PL module is
> optional.
> > +
> > +  AMS Channel Details
> > +  ```````````````````
> > +  Sysmon Block  |Channel|                       Details
> |Measurement
> > +                |Number |                                                               |Type
> > +  -----------------------------------------------------------------------------------------
> ----------------
> > +  AMS CTRL      |0      |System PLLs voltage measurement, VCC_PSPLL.
> |Voltage
> > +                |1      |Battery voltage measurement, VCC_PSBATT.
> |Voltage
> > +                |2      |PL Internal voltage measurement, VCCINT.
> |Voltage
> > +                |3      |Block RAM voltage measurement, VCCBRAM.
> |Voltage
> > +                |4      |PL Aux voltage measurement, VCCAUX.
> |Voltage
> > +                |5      |Voltage measurement for six DDR I/O PLLs,
> VCC_PSDDR_PLL.       |Voltage
> > +                |6      |VCC_PSINTFP_DDR voltage measurement.
> |Voltage
> > +  -----------------------------------------------------------------------------------------
> ----------------
> > +  PS Sysmon     |7      |LPD temperature measurement.
> |Temperature
> > +                |8      |FPD temperature measurement (REMOTE).
> |Temperature
> > +                |9      |VCC PS LPD voltage measurement (supply1).
> |Voltage
> > +                |10     |VCC PS FPD voltage measurement (supply2).
> |Voltage
> > +                |11     |PS Aux voltage reference (supply3).                            |Voltage
> > +                |12     |DDR I/O VCC voltage measurement.
> |Voltage
> > +                |13     |PS IO Bank 503 voltage measurement (supply5).
> |Voltage
> > +                |14     |PS IO Bank 500 voltage measurement (supply6).
> |Voltage
> > +                |15     |VCCO_PSIO1 voltage measurement.
> |Voltage
> > +                |16     |VCCO_PSIO2 voltage measurement.
> |Voltage
> > +                |17     |VCC_PS_GTR voltage measurement (VPS_MGTRAVCC).
> |Voltage
> > +                |18     |VTT_PS_GTR voltage measurement (VPS_MGTRAVTT).
> |Voltage
> > +                |19     |VCC_PSADC voltage measurement.
> |Voltage
> > +  -----------------------------------------------------------------------------------------
> ----------------
> > +  PL Sysmon     |20     |PL temperature measurement.
> |Temperature
> > +                |21     |PL Internal voltage measurement, VCCINT.
> |Voltage
> > +                |22     |PL Auxiliary voltage measurement, VCCAUX.
> |Voltage
> > +                |23     |ADC Reference P+ voltage measurement.
> |Voltage
> > +                |24     |ADC Reference N- voltage measurement.
> |Voltage
> > +                |25     |PL Block RAM voltage measurement, VCCBRAM.
> |Voltage
> > +                |26     |LPD Internal voltage measurement, VCC_PSINTLP
> (supply4).       |Voltage
> > +                |27     |FPD Internal voltage measurement, VCC_PSINTFP
> (supply5).       |Voltage
> > +                |28     |PS Auxiliary voltage measurement (supply6).
> |Voltage
> > +                |29     |PL VCCADC voltage measurement (vccams).
> |Voltage
> > +                |30     |Differential analog input signal voltage measurment.
> |Voltage
> > +                |31     |VUser0 voltage measurement (supply7).
> |Voltage
> > +                |32     |VUser1 voltage measurement (supply8).
> |Voltage
> > +                |33     |VUser2 voltage measurement (supply9).
> |Voltage
> > +                |34     |VUser3 voltage measurement (supply10).
> |Voltage
> > +                |35     |Auxiliary ch 0 voltage measurement (VAux0).
> |Voltage
> > +                |36     |Auxiliary ch 1 voltage measurement (VAux1).
> |Voltage
> > +                |37     |Auxiliary ch 2 voltage measurement (VAux2).
> |Voltage
> > +                |38     |Auxiliary ch 3 voltage measurement (VAux3).
> |Voltage
> > +                |39     |Auxiliary ch 4 voltage measurement (VAux4).
> |Voltage
> > +                |40     |Auxiliary ch 5 voltage measurement (VAux5).
> |Voltage
> > +                |41     |Auxiliary ch 6 voltage measurement (VAux6).
> |Voltage
> > +                |42     |Auxiliary ch 7 voltage measurement (VAux7).
> |Voltage
> > +                |43     |Auxiliary ch 8 voltage measurement (VAux8).
> |Voltage
> > +                |44     |Auxiliary ch 9 voltage measurement (VAux9).
> |Voltage
> > +                |45     |Auxiliary ch 10 voltage measurement (VAux10).
> |Voltage
> > +                |46     |Auxiliary ch 11 voltage measurement (VAux11).
> |Voltage
> > +                |47     |Auxiliary ch 12 voltage measurement (VAux12).
> |Voltage
> > +                |48     |Auxiliary ch 13 voltage measurement (VAux13).
> |Voltage
> > +                |49     |Auxiliary ch 14 voltage measurement (VAux14).
> |Voltage
> > +                |50     |Auxiliary ch 15 voltage measurement (VAux15).
> |Voltage
> > +
> > + --------------------------------------------------------------------
> > + ------------------------------------
> > +
> > +properties:
> > +  compatible:
> > +    enum:
> > +      - xlnx,zynqmp-ams
> > +
> > +  interrupts:
> > +    maxItems: 1
> > +
> > +  reg:
> > +    description: AMS Controller register space
> > +    maxItems: 1
> > +
> > +  ranges:
> > +    description:
> > +      Maps the child address space for PS and/or PL.
> > +    maxItems: 1
> > +
> > +  '#address-cells':
> > +    const: 1
> > +
> > +  '#size-cells':
> > +    const: 1
> > +
> > +  '#io-channel-cells':
> > +    const: 1
> > +
> > +patternProperties:
> > +  "^ams-ps@0,400$":
> 
> If your going to hardcode the unit-address, then it's a fixed string and should
> be under 'properties' instead.
Can you point me to an example?
When I tried putting it under just properties, I was not able to do so and was getting errors when I ran check_dt_bindings.
The only way I was not getting the error was by putting it under pattern properties.

My node looked something like this,

   "ams-ps@0":
	type:object
	...
	...

> 
> The unit-address is also wrong. This is memory-mapped ranges, right? If so,
> this should just be '0' and the next one '400'.

I will fix this.
> 
> > +    type: object
> > +    description: |
> > +      PS (Processing System) SYSMON is memory mapped to PS. This block
> has
> > +      built-in alarm generation logic that is used to interrupt the processor
> > +      based on condition set.
> > +
> > +    properties:
> > +      compatible:
> > +        enum:
> > +          - xlnx,zynqmp-ams-ps
> > +
> > +      reg:
> > +        description: Register Space for PS-SYSMON
> > +        maxItems: 1
> > +
> > +    required:
> > +      - compatible
> > +      - reg
> > +
> > +    additionalProperties: false
> > +
> > +  "^ams-pl@400,400$":
> > +    type: object
> > +    description:
> > +      PL-SYSMON is capable of monitoring off chip voltage and temperature.
> > +      PL-SYSMON block has DRP, JTAG and I2C interface to enable
> monitoring
> > +      from external master. Out of this interface currently only DRP is
> > +      supported. This block has alarm generation logic that is used to
> > +      interrupt the processor based on condition set.
> > +
> > +    properties:
> > +      compatible:
> > +        items:
> > +          - enum:
> > +              - xlnx,zynqmp-ams-pl
> > +
> > +      reg:
> > +        description: Register Space for PL-SYSMON.
> > +        maxItems: 1
> > +
> > +      '#address-cells':
> > +        const: 1
> > +
> > +      '#size-cells':
> > +        const: 0
> > +
> > +    patternProperties:
> > +      "^channel@([2-4][0-9]|50)$":
> > +        type: object
> > +        description:
> > +          Describes the external channels connected.
> > +
> > +        properties:
> > +          reg:
> > +            description:
> > +              Pair of pins the channel is connected to. This value is
> > +              same as Channel Number for a particular channel.
> > +            minimum: 20
> > +            maximum: 50
> > +
> > +          xlnx,bipolar:
> 
> Don't we have a common property for this now?
> 
> > +            $ref: /schemas/types.yaml#/definitions/flag
> > +            type: boolean
> > +            description:
> > +              If the set channel is used in bipolar mode.
> > +
> > +        required:
> > +          - reg
> > +
> > +        additionalProperties: false
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - ranges
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +    bus {
> > +        #address-cells = <2>;
> > +        #size-cells = <2>;
> > +
> > +        xilinx_ams: ams@ffa50000 {
> > +            compatible = "xlnx,zynqmp-ams";
> > +            interrupt-parent = <&gic>;
> > +            interrupts = <0 56 4>;
> > +            reg = <0x0 0xffa50000 0x0 0x800>;
> > +            #address-cells = <1>;
> > +            #size-cells = <1>;
> > +            #io-channel-cells = <1>;
> > +            ranges = <0 0 0xffa50800 0x800>;
> > +
> > +            ams_ps: ams-ps@0,400 {
> > +                compatible = "xlnx,zynqmp-ams-ps";
> > +                reg = <0 0x400>;
> > +            };
> > +
> > +            ams_pl: ams-pl@400,400 {
> > +                compatible = "xlnx,zynqmp-ams-pl";
> > +                reg = <0x400 0x400>;
> > +                #address-cells = <1>;
> > +                #size-cells = <0>;
> > +                channel@30 {
> > +                    reg = <30>;
> > +                    xlnx,bipolar;
> > +                };
> > +                channel@31 {
> > +                    reg = <31>;
> > +                };
> > +                channel@38 {
> > +                    reg = <38>;
> > +                    xlnx,bipolar;
> > +                };
> > +            };
> > +        };
> > +    };
> > --
> > 2.17.1
> >
> >