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

Lukas Wunner
2023-09-26T19:16:14Z

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
+
+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.
+
+ 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 {
+ 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";
+ reg = <0>;
+ resets = <&tpm_reset>;
+ };
+ };
--
2.40.1