On Tue, Jul 19, 2016 at 08:41:24PM -0700, Andrey Pronin wrote: > Add TPM2.0 PTP FIFO compatible SPI interface for chips with Cr50 > firmware. Several timing-related properties that may differ from > one firmware version to another are added to devicetree. > Document these properties. > > Signed-off-by: Andrey Pronin <apronin@xxxxxxxxxxxx> > --- > .../devicetree/bindings/security/tpm/cr50_spi.txt | 32 ++++++++++++++++++++++ > 1 file changed, 32 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..f212b6b > --- /dev/null > +++ b/Documentation/devicetree/bindings/security/tpm/cr50_spi.txt > @@ -0,0 +1,32 @@ > +* H1 Secure Microcontroller with Cr50 Firmware on SPI Bus. > + > +H1 Secure Microcontroller running Cr50 firmware provides several > +functions, including TPM-like functionality. It communicates over > +SPI using the FIFO protocol described in the PTP Spec, section 6. > + > +Required properties: > +- compatible: Should be "google,cr50". > +- spi-max-frequency: Maximum SPI frequency. > + > +Optional properties: > +- access-delay-ms: Required delay between subsequent transactions on SPI. As I mentioned, there may be common properties. It doesn't seem you looked, so I did: - spi-rx-delay-us - (optional) Microsecond delay after a read transfer. - spi-tx-delay-us - (optional) Microsecond delay after a write transfer. Seems to me setting one or both of these should work for you. > +- sleep-delay-ms: Time after the last SPI activity, after which the chip > + may go to sleep. > +- wake-start-delay-ms: Time after initiating wake up before the chip is > + ready to accept commands over SPI. I also asked why these 2 can't be hard-coded in the driver? > + > +Example: > + > +&spi0 { > + status = "okay"; > + > + cr50@0 { > + compatible = "google,cr50"; > + reg = <0>; > + spi-max-frequency = <800000>; > + > + access-delay-ms = <2>; > + sleep-delay-ms = <1000>; > + wake-start-delay-ms = <60>; > + }; > +}; > -- > 2.6.6 > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html