Re: [PATCH 1/3] dt-bindings: hwmon: Add Infineon TDA38640

[Rob Herring <robh@kernel.org>]

On Tue, Jul 25, 2023 at 01:40:26PM +0200, Naresh Solanki wrote:
> From: Patrick Rudolph <patrick.rudolph@9elements.com>
> 
> The TDA38640 has a bug in SVID mode and to enable a workaround
> remove the TDA38640 from trivial-devices and add a complete schema.
> 
> The schema adds the custom property 'infineon,en-pin-fixed-level' to
> signal a fixed level on the ENABLE pin and to enable the workaround.
> When the ENABLE pin is left floating it's internally pulled low.
> 
> If not specified the driver will continue to use the PMBUS_OPERATION
> register to enable the regulator. When specified the driver will use
> the PMBUS_ON_OFF_CONFIG register to enable the regulator.
> 
> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
> Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
> ---
>  .../hwmon/pmbus/infineon,tda38640.yaml        | 50 +++++++++++++++++++
>  .../devicetree/bindings/trivial-devices.yaml  |  2 -
>  2 files changed, 50 insertions(+), 2 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/hwmon/pmbus/infineon,tda38640.yaml
> 
> diff --git a/Documentation/devicetree/bindings/hwmon/pmbus/infineon,tda38640.yaml b/Documentation/devicetree/bindings/hwmon/pmbus/infineon,tda38640.yaml
> new file mode 100644
> index 000000000000..520112e4e271
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/pmbus/infineon,tda38640.yaml
> @@ -0,0 +1,50 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +
> +$id: http://devicetree.org/schemas/hwmon/pmbus/infineon,tda38640.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Infineon TDA38640 Synchronous Buck Regulator with SVID and I2C
> +
> +description: |
> +  The Infineon TDA38640 is a 40A Single-voltage Synchronous Buck
> +  Regulator with SVID and I2C designed for Industrial use.
> +
> +  Datasheet: https://www.infineon.com/dgdl/Infineon-TDA38640-0000-DataSheet-v02_04-EN.pdf?fileId=8ac78c8c80027ecd018042f2337f00c9
> +
> +properties:
> +  compatible:
> +    enum:
> +      - infineon,tda38640
> +
> +  reg:
> +    maxItems: 1
> +
> +  infineon,en-pin-fixed-level:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description: |
> +      Fixed level of the ENABLE pin. When specified the PMBUS_ON_OFF_CONFIG
> +      register is used to enable the regulator instead of the PMBUS_OPERATION
> +      register to workaround a bug of the tda38640 when operating in SVID-mode.
> +      If the ENABLE pin is left floating the internal pull-down causes a low
> +      level on the pin.

Neither this nor the commit message answers how do I decide if I set 
this property or not? How you work-around it is not that relevant to the 
binding.

> +
> +required:
> +  - compatible
> +  - reg
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    i2c {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        tda38640@40 {
> +            compatible = "infineon,tda38640";
> +            reg = <0x40>;
> +        };
> +    };
> +
> diff --git a/Documentation/devicetree/bindings/trivial-devices.yaml b/Documentation/devicetree/bindings/trivial-devices.yaml
> index 6e24c4d25ec3..2b1fbb2a672b 100644
> --- a/Documentation/devicetree/bindings/trivial-devices.yaml
> +++ b/Documentation/devicetree/bindings/trivial-devices.yaml
> @@ -151,8 +151,6 @@ properties:
>            - infineon,slb9645tt
>              # Infineon SLB9673 I2C TPM 2.0
>            - infineon,slb9673
> -            # Infineon TDA38640 Voltage Regulator
> -          - infineon,tda38640
>              # Infineon TLV493D-A1B6 I2C 3D Magnetic Sensor
>            - infineon,tlv493d-a1b6
>              # Infineon Multi-phase Digital VR Controller xdpe11280
> 
> base-commit: 55612007f16b5d7b1fb83a7b0f5bb686829db7c7
> -- 
> 2.41.0
>