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

Krzysztof Kozlowski
2023-09-27T07:48:54Z

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