[v6,6/7] dt-bindings: tpm: Add YAML schema for TPM TIS I2C options

From: Amir Mizinski <amirmizi6@gmail.com>

Added a YAML schema to support tpm tis i2c realted dt-bindings for the I2c
PTP based physical layer.

This patch adds the documentation for corresponding device tree bindings of
I2C based Physical TPM.
Refer to the 'I2C Interface Definition' section in
'TCG PC Client PlatformTPMProfile(PTP) Specification' publication
for specification.

Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>
---
 .../bindings/security/tpm/tpm-tis-i2c.yaml         | 47 ++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/security/tpm/tpm-tis-i2c.yaml

On Tue, Apr 07, 2020 at 07:20:43PM +0300, amirmizi6@gmail.com wrote:
> From: Amir Mizinski <amirmizi6@gmail.com>
> 
> Added a YAML schema to support tpm tis i2c realted dt-bindings for the I2c
> PTP based physical layer.
> 
> This patch adds the documentation for corresponding device tree bindings of
> I2C based Physical TPM.
> Refer to the 'I2C Interface Definition' section in
> 'TCG PC Client PlatformTPMProfile(PTP) Specification' publication
> for specification.
> 
> Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>
> ---
>  .../bindings/security/tpm/tpm-tis-i2c.yaml         | 47 ++++++++++++++++++++++
>  1 file changed, 47 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/security/tpm/tpm-tis-i2c.yaml
> 
> diff --git a/Documentation/devicetree/bindings/security/tpm/tpm-tis-i2c.yaml b/Documentation/devicetree/bindings/security/tpm/tpm-tis-i2c.yaml
> new file mode 100644
> index 0000000..13d7c2c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/security/tpm/tpm-tis-i2c.yaml
> @@ -0,0 +1,47 @@
> +# SPDX-License-Identifier: GPL-2.0
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/security/tpm/tpm-tis-i2c.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: I2C PTP based TPM Device Tree Bindings
> +
> +maintainers:
> +  - Amir Mizinski <amirmizi6@gmail.com>
> +
> +description:
> +  Device Tree Bindings for I2C based Trusted Platform Module(TPM).
> +
> +properties:
> +  compatible:
> +    contains:
> +      const: tcg,tpm-tis-i2c

This is not sufficient. I assume you are testing on some specific TPM 
chip.

> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupt:
> +    maxItems: 1
> +
> +  crc-checksum:
> +    $ref: /schemas/types.yaml#/definitions/flag
> +    description:
> +      CRC checksum enable.

Why would you not want CRC? Some chips support and some don't? If so, 
the compatible for the chip should imply that.

> +
> +required:
> +  - compatible
> +  - reg
> +
> +examples:
> +  - |
> +    i2c {
> +      #address-cells = <1>;
> +      #size-cells = <0>;
> +
> +      tpm-tis-i2c@2e {

tpm@2e

> +        compatible = "tcg,tpm-tis-i2c";
> +        reg = <0x2e>;
> +        crc-checksum;
> +      };
> +    };
> +...
> -- 
> 2.7.4
>

On 2020-04-15 15:20, Rob Herring wrote:
> On Tue, Apr 07, 2020 at 07:20:43PM +0300, amirmizi6@gmail.com wrote:
>> From: Amir Mizinski <amirmizi6@gmail.com>
>>
>> Added a YAML schema to support tpm tis i2c realted dt-bindings for the I2c
>> PTP based physical layer.
>>
>> This patch adds the documentation for corresponding device tree bindings of
>> I2C based Physical TPM.
>> Refer to the 'I2C Interface Definition' section in
>> 'TCG PC Client PlatformTPMProfile(PTP) Specification' publication
>> for specification.
>>
>> Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>
>> ---
>>  .../bindings/security/tpm/tpm-tis-i2c.yaml         | 47 ++++++++++++++++++++++
>>  1 file changed, 47 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/security/tpm/tpm-tis-i2c.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/security/tpm/tpm-tis-i2c.yaml b/Documentation/devicetree/bindings/security/tpm/tpm-tis-i2c.yaml
>> new file mode 100644
>> index 0000000..13d7c2c
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/security/tpm/tpm-tis-i2c.yaml
>> @@ -0,0 +1,47 @@
>> +# SPDX-License-Identifier: GPL-2.0
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/security/tpm/tpm-tis-i2c.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: I2C PTP based TPM Device Tree Bindings
>> +
>> +maintainers:
>> +  - Amir Mizinski <amirmizi6@gmail.com>
>> +
>> +description:
>> +  Device Tree Bindings for I2C based Trusted Platform Module(TPM).
>> +
>> +properties:
>> +  compatible:
>> +    contains:
>> +      const: tcg,tpm-tis-i2c
>
> This is not sufficient. I assume you are testing on some specific TPM
> chip.
>

I am, but this implementation follows the "TCG PC client Device Driver Design Principles for TPM 2.0"
It's not meant solely for out chip.

>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  interrupt:
>> +    maxItems: 1
>> +
>> +  crc-checksum:
>> +    $ref: /schemas/types.yaml#/definitions/flag
>> +    description:
>> +      CRC checksum enable.
>
> Why would you not want CRC? Some chips support and some don't? If so,
> the compatible for the chip should imply that.
>

There's an Enable/Disable CRC option in the TPM chip, not all vendors
use this by default.

>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +
>> +examples:
>> +  - |
>> +    i2c {
>> +      #address-cells = <1>;
>> +      #size-cells = <0>;
>> +
>> +      tpm-tis-i2c@2e {
>
> tpm@2e
>

I understand why i should remove "i2c", but i think it should be "tpm_tis@2e".
Respectively with "tpm_tis_spi.txt" and "tpm_tis_mmio.txt".

>> +        compatible = "tcg,tpm-tis-i2c";
>> +        reg = <0x2e>;
>> +        crc-checksum;
>> +      };
>> +    };
>> +...
>> --
>> 2.7.4
>>

Thank you for your feedback.
Best regards,
Amir Mizinski