Re: [PATCH 1/2] dt-bindings: reset: Add Infineon SLB9670 TPM reset driver

[Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>]

On 26/09/2023 21:09, Lukas Wunner wrote:
> A new reset driver is about to be added to perform the reset sequence of
> the Infineon SLB9670 Trusted Platform Module.
> 
> Document its device tree bindings.
> 
> Signed-off-by: Lukas Wunner <lukas@wunner.de>
> ---
>  .../bindings/reset/infineon,slb9670-reset.yaml     | 68 ++++++++++++++++++++++
>  1 file changed, 68 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/reset/infineon,slb9670-reset.yaml
> 
> diff --git a/Documentation/devicetree/bindings/reset/infineon,slb9670-reset.yaml b/Documentation/devicetree/bindings/reset/infineon,slb9670-reset.yaml
> new file mode 100644
> index 00000000..b1e23d47
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/reset/infineon,slb9670-reset.yaml
> @@ -0,0 +1,68 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/reset/infineon,slb9670-reset.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Infineon SLB9670 TPM Reset Driver

Sorry, bindings are for hardware, not for drivers.

> +
> +maintainers:
> +  - Lukas Wunner <lukas@wunner.de>
> +
> +description: |
> +  The Infineon SLB9670 Trusted Platform Module requires a specific reset
> +  sequence on its RST# pin which is documented in sections 5.4 and 5.5 of
> +  the datasheet [1]. This driver performs the reset sequence using a GPIO.

Sorry, bindings are for hardware, not for drivers. I don't see the point
for this binding, especially that you refer to drivers. Why it cannot be
just part of other device?


> +
> +  The sequence with minimum wait intervals is as follows:
> +  deassert RST#
> +  wait at least 60 ms
> +  assert RST#
> +  wait at least 2 usecs
> +  deassert RST#
> +  wait at least 60 ms
> +  assert RST#
> +  wait at least 2 usecs
> +  deassert RST#
> +  wait at least 60 ms before issuing the first TPM command
> +
> +  [1] https://www.infineon.com/dgdl/Infineon-SLB%209670VQ2.0-DataSheet-v01_04-EN.pdf?fileId=5546d4626fc1ce0b016fc78270350cd6
> +
> +properties:
> +  compatible:
> +    enum:
> +      - infineon,slb9670-reset
> +
> +  reset-gpios:
> +    maxItems: 1
> +    description: Reference to the GPIO connected to the RST# pin.
> +
> +  "#reset-cells":
> +    const: 0
> +
> +required:
> +  - compatible
> +  - reset-gpios
> +  - "#reset-cells"
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +    tpm_reset: reset-controller {

No need for label.

> +        compatible = "infineon,slb9670-reset";
> +        #reset-cells = <0>;
> +        reset-gpios = <&gpio 0 GPIO_ACTIVE_LOW>;
> +    };
> +
> +    spi {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        tpm@0 {
> +            compatible = "infineon,slb9670";

Drop node, not related to the binding. We never keep consumers in
binding providers.

> +            reg = <0>;
> +            resets = <&tpm_reset>;
> +        };
> +    };

Best regards,
Krzysztof