diff options
author | Richard Cochran <richardcochran@gmail.com> | 2011-04-22 10:03:54 (GMT) |
---|---|---|
committer | John Stultz <john.stultz@linaro.org> | 2011-05-23 20:10:14 (GMT) |
commit | c78275f366c687b5b3ead3d99fc96d1f02d38a8e (patch) | |
tree | 279a8cccfc56fd347b4864c3f400935f18244a5f /Documentation/devicetree/bindings/net | |
parent | d94ba80ebbea17f036cecb104398fbcd788aa742 (diff) | |
download | linux-c78275f366c687b5b3ead3d99fc96d1f02d38a8e.tar.xz |
ptp: Added a clock that uses the eTSEC found on the MPC85xx.
The eTSEC includes a PTP clock with quite a few features. This patch adds
support for the basic clock adjustment functions, plus two external time
stamps, one alarm, and the PPS callback.
Signed-off-by: Richard Cochran <richard.cochran@omicron.at>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Diffstat (limited to 'Documentation/devicetree/bindings/net')
-rw-r--r-- | Documentation/devicetree/bindings/net/fsl-tsec-phy.txt | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/net/fsl-tsec-phy.txt b/Documentation/devicetree/bindings/net/fsl-tsec-phy.txt index edb7ae1..2c6be03 100644 --- a/Documentation/devicetree/bindings/net/fsl-tsec-phy.txt +++ b/Documentation/devicetree/bindings/net/fsl-tsec-phy.txt @@ -74,3 +74,57 @@ Example: interrupt-parent = <&mpic>; phy-handle = <&phy0> }; + +* Gianfar PTP clock nodes + +General Properties: + + - compatible Should be "fsl,etsec-ptp" + - reg Offset and length of the register set for the device + - interrupts There should be at least two interrupts. Some devices + have as many as four PTP related interrupts. + +Clock Properties: + + - fsl,tclk-period Timer reference clock period in nanoseconds. + - fsl,tmr-prsc Prescaler, divides the output clock. + - fsl,tmr-add Frequency compensation value. + - fsl,tmr-fiper1 Fixed interval period pulse generator. + - fsl,tmr-fiper2 Fixed interval period pulse generator. + - fsl,max-adj Maximum frequency adjustment in parts per billion. + + These properties set the operational parameters for the PTP + clock. You must choose these carefully for the clock to work right. + Here is how to figure good values: + + TimerOsc = system clock MHz + tclk_period = desired clock period nanoseconds + NominalFreq = 1000 / tclk_period MHz + FreqDivRatio = TimerOsc / NominalFreq (must be greater that 1.0) + tmr_add = ceil(2^32 / FreqDivRatio) + OutputClock = NominalFreq / tmr_prsc MHz + PulseWidth = 1 / OutputClock microseconds + FiperFreq1 = desired frequency in Hz + FiperDiv1 = 1000000 * OutputClock / FiperFreq1 + tmr_fiper1 = tmr_prsc * tclk_period * FiperDiv1 - tclk_period + max_adj = 1000000000 * (FreqDivRatio - 1.0) - 1 + + The calculation for tmr_fiper2 is the same as for tmr_fiper1. The + driver expects that tmr_fiper1 will be correctly set to produce a 1 + Pulse Per Second (PPS) signal, since this will be offered to the PPS + subsystem to synchronize the Linux clock. + +Example: + + ptp_clock@24E00 { + compatible = "fsl,etsec-ptp"; + reg = <0x24E00 0xB0>; + interrupts = <12 0x8 13 0x8>; + interrupt-parent = < &ipic >; + fsl,tclk-period = <10>; + fsl,tmr-prsc = <100>; + fsl,tmr-add = <0x999999A4>; + fsl,tmr-fiper1 = <0x3B9AC9F6>; + fsl,tmr-fiper2 = <0x00018696>; + fsl,max-adj = <659999998>; + }; |