Re: [PATCH 1/2] tpm: devicetree: document properties for cr50

[Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

On Thu, Jul 14, 2016 at 07:20:17PM -0700, Andrey Pronin wrote:
> Add TPM2.0-compatible interface to Cr50. Document its properties
> in devicetree.
> 
> Signed-off-by: Andrey Pronin <apronin-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
> ---
>  .../devicetree/bindings/security/tpm/cr50_spi.txt  | 30 ++++++++++++++++++++++
>  1 file changed, 30 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/security/tpm/cr50_spi.txt
> 
> diff --git a/Documentation/devicetree/bindings/security/tpm/cr50_spi.txt b/Documentation/devicetree/bindings/security/tpm/cr50_spi.txt
> new file mode 100644
> index 0000000..1b05e51
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/security/tpm/cr50_spi.txt
> @@ -0,0 +1,30 @@
> +* Cr50 Chip on SPI.
> +
> +TCG PTP FIFO Compliant Interface to Cr50 on SPI bus.
> +
> +Required properties:
> +- compatible: Should be "google,cr50_spi".

I agree with dropping '_spi'. The interface is defined by the parent 
device.

> +- spi-max-frequency: Maximum SPI frequency.
> +
> +Optional properties:
> +- access-delay-msec: Required delay between subsequent transactions on SPI.

There may be a standard property for this...

> +- sleep-delay-msec: Time after the last SPI activity, after which the chip
> +  may go to sleep.
> +- wake-start-delay-msec: Time after initiating wake up before the chip is
> +  ready to accept commands over SPI.

Use the standard unit '-ms' instead of '-msec'.

Do these times really vary much and need to be in DT?

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