dt-bindings: tpm: Consolidate TCG TIS bindings

A significant number of Trusted Platform Modules conform to the "TIS"
specification published by the Trusted Computing Group ("TCG PC Client
Specific TPM Interface Specification").  These chips typically use an
SPI, I²C or LPC bus as transport (via MMIO in the latter case).  Some
of them even support multiple of those buses (selectable through a
config strap) or the same chip is available in multiple SKUs, each with
a different bus interface.

The devicetree bindings for these TPMs have not been converted to DT
schema yet and are spread out across 3 generic files and 2 chip-specific
files.  A few TPM compatible strings were added to trivial-devices.yaml
even though additional properties are documented in the plaintext
bindings.

Consolidate the devicetree bindings into 3 yaml files, one per bus.

Move common properties to a separate tpm-common.yaml.

Document compatible strings which are supported by the TPM TIS driver
but were neglected to be added to the devicetree bindings.

Document the memory-region property recently introduced by commit
1e2714bb83fc ("tpm: Add reserved memory event log").

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/953fd4c7519030db88e5b5e12ab6307414ebdd21.1702806810.git.lukas@wunner.de
Signed-off-by: Rob Herring <robh@kernel.org>

1 files changed, 75 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/tpm/tcg,tpm_tis-spi.yaml b/Documentation/devicetree/bindings/tpm/tcg,tpm_tis-spi.yaml
new file mode 100644
index 000000000000..c3413b47ac3d
--- /dev/null
+++ b/Documentation/devicetree/bindings/tpm/tcg,tpm_tis-spi.yaml
@@ -0,0 +1,75 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/tpm/tcg,tpm_tis-spi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: SPI-attached Trusted Platform Module conforming to TCG TIS specification
+
+maintainers:
+  - Lukas Wunner <lukas@wunner.de>
+
+description: |
+  The Trusted Computing Group (TCG) has defined a multi-vendor standard
+  for accessing a TPM chip.  It can be transported over various buses,
+  one of them being SPI.  The standard is named:
+  TCG PC Client Specific TPM Interface Specification (TIS)
+  https://trustedcomputinggroup.org/resource/pc-client-work-group-pc-client-specific-tpm-interface-specification-tis/
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - infineon,slb9670
+          - st,st33htpm-spi
+          - st,st33zp24-spi
+      - const: tcg,tpm_tis-spi
+
+allOf:
+  - $ref: tpm-common.yaml#
+  - $ref: /schemas/spi/spi-peripheral-props.yaml#
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: st,st33zp24-spi
+    then:
+      properties:
+        spi-max-frequency:
+          maximum: 10000000
+
+required:
+  - compatible
+  - reg
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        tpm@0 {
+            reg = <0>;
+            compatible = "infineon,slb9670", "tcg,tpm_tis-spi";
+            spi-max-frequency = <10000000>;
+        };
+    };
+
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        tpm@0 {
+            reg = <0>;
+            compatible = "st,st33zp24-spi", "tcg,tpm_tis-spi";
+            spi-max-frequency = <10000000>;
+            interrupt-parent = <&gpio5>;
+            interrupts = <7 IRQ_TYPE_LEVEL_HIGH>;
+            lpcpd-gpios = <&gpio5 15 GPIO_ACTIVE_HIGH>;
+        };
+    };