Re: [PATCH 1/4] dt-bindings: mfd: Add bindings for Ampere Altra SMPro drivers

[Quan Nguyen <quan@os.amperecomputing.com>]

On 07/03/2021 03:58, Rob Herring wrote:
> On Thu, Feb 25, 2021 at 05:18:51PM +0700, Quan Nguyen wrote:
>> Adds device tree bindings for SMPro drivers found on the Mt.Jade hardware
>> reference platform with Ampere's Altra Processor family.
>>
>> Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
>> ---
>>   .../bindings/hwmon/ampere,ac01-hwmon.yaml     | 27 ++++++
>>   .../bindings/mfd/ampere,ac01-smpro.yaml       | 82 +++++++++++++++++++
>>   2 files changed, 109 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/hwmon/ampere,ac01-hwmon.yaml
>>   create mode 100644 Documentation/devicetree/bindings/mfd/ampere,ac01-smpro.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/hwmon/ampere,ac01-hwmon.yaml b/Documentation/devicetree/bindings/hwmon/ampere,ac01-hwmon.yaml
>> new file mode 100644
>> index 000000000000..d13862ba646b
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/hwmon/ampere,ac01-hwmon.yaml
>> @@ -0,0 +1,27 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/hwmon/ampere,ac01-hwmon.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Hardware monitoring driver for the Ampere Altra SMPro
>> +
>> +maintainers:
>> +  - Quan Nguyen <quan@os.amperecomputing.com>
>> +
>> +description: |
>> +  This module is part of the Ampere Altra SMPro multi-function device. For more
>> +  details see ../mfd/ampere,ac01-smpro.yaml.
>> +
>> +properties:
>> +  compatible:
>> +    enum:
>> +      - ampere,ac01-hwmon
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +required:
>> +  - compatible
>> +
>> +additionalProperties: false
>> diff --git a/Documentation/devicetree/bindings/mfd/ampere,ac01-smpro.yaml b/Documentation/devicetree/bindings/mfd/ampere,ac01-smpro.yaml
>> new file mode 100644
>> index 000000000000..06b0239413ae
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/mfd/ampere,ac01-smpro.yaml
>> @@ -0,0 +1,82 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/mfd/ampere,ac01-smpro.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Ampere Altra SMPro firmware driver
>> +
>> +maintainers:
>> +  - Quan Nguyen <quan@os.amperecomputing.com>
>> +
>> +description: |
>> +  Ampere Altra SMPro firmware may contain different blocks like hardware
>> +  monitoring, error monitoring and other miscellaneous features.
>> +
>> +properties:
>> +  compatible:
>> +    const: ampere,ac01-smpro
>> +
>> +  reg:
>> +    description:
>> +      I2C device address.
>> +    maxItems: 1
>> +
>> +  "#address-cells":
>> +    const: 1
>> +
>> +  "#size-cells":
>> +    const: 0
>> +
>> +patternProperties:
>> +  "^hwmon(@[0-9a-f]+)?$":
>> +    $ref: ../hwmon/ampere,ac01-hwmon.yaml
>> +
>> +  "^misc(@[0-9a-f]+)?$":
>> +    type: object
>> +    description: Ampere Altra SMPro Misc driver
>> +    properties:
>> +      compatible:
>> +        const: "ampere,ac01-misc"
>> +
>> +  "^errmon(@[0-9a-f]+)?$":
>> +    type: object
>> +    description: Ampere Altra SMPro Error Monitor driver
>> +    properties:
>> +      compatible:
>> +        const: "ampere,ac01-errmon"
>> +
>> +required:
>> +  - "#address-cells"
>> +  - "#size-cells"
>> +  - compatible
>> +  - reg
>> +
>> +additionalProperties: false
>> +
>> +examples:
>> +  - |
>> +    i2c {
>> +        #address-cells = <1>;
>> +        #size-cells = <0>;
>> +
>> +        smpro@4f {
>> +            compatible = "ampere,ac01-smpro";
>> +            reg = <0x4f>;
>> +            #address-cells = <1>;
>> +            #size-cells = <0>;
>> +
>> +            hwmon {
>> +                compatible = "ampere,ac01-hwmon";
>> +            };
>> +
>> +            misc {
>> +                compatible = "ampere,ac01-misc";
>> +            };
>> +
>> +            errmon {
>> +                compatible = "ampere,ac01-errmon";
>> +            };
> 
> No of these have any properties or resources, why do you need them? DT
> is not the only way to instantiate drivers...
> 
Thanks Rob,

SMpro (MFD driver) reports various data included hwmon-related data, RAS 
error monitor and other miscellaneous information, and we need three 
difference drivers for these purposes. And that is why hwmon, misc and 
errmon nodes are added to instantiate these drivers.

I'm wonder if this is the right way or if there's anything that can be 
improved ?

- Quan