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>

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>;
+	};