tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2%YAML 1.2
3---
4$id: http://devicetree.org/schemas/ptp/fsl,ptp.yaml#
5$schema: http://devicetree.org/meta-schemas/core.yaml#
6
7title: Freescale QorIQ 1588 timer based PTP clock
8
9maintainers:
10 - Frank Li <Frank.Li@nxp.com>
11
12properties:
13 compatible:
14 oneOf:
15 - enum:
16 - fsl,etsec-ptp
17 - fsl,fman-ptp-timer
18 - fsl,dpaa2-ptp
19 - items:
20 - const: pci1957,ee02
21 - const: fsl,enetc-ptp
22
23 reg:
24 maxItems: 1
25
26 interrupts:
27 maxItems: 1
28
29 clocks:
30 maxItems: 1
31
32 fsl,cksel:
33 $ref: /schemas/types.yaml#/definitions/uint32
34 description: |
35 Timer reference clock source.
36
37 Reference clock source is determined by the value, which is holded
38 in CKSEL bits in TMR_CTRL register. "fsl,cksel" property keeps the
39 value, which will be directly written in those bits, that is why,
40 according to reference manual, the next clock sources can be used:
41
42 For eTSEC,
43 <0> - external high precision timer reference clock (TSEC_TMR_CLK
44 input is used for this purpose);
45 <1> - eTSEC system clock;
46 <2> - eTSEC1 transmit clock;
47 <3> - RTC clock input.
48
49 For DPAA FMan,
50 <0> - external high precision timer reference clock (TMR_1588_CLK)
51 <1> - MAC system clock (1/2 FMan clock)
52 <2> - reserved
53 <3> - RTC clock oscillator
54
55 fsl,tclk-period:
56 $ref: /schemas/types.yaml#/definitions/uint32
57 description: Timer reference clock period in nanoseconds.
58
59 fsl,tmr-prsc:
60 $ref: /schemas/types.yaml#/definitions/uint32
61 description: Prescaler, divides the output clock.
62
63 fsl,tmr-add:
64 $ref: /schemas/types.yaml#/definitions/uint32
65 description: Frequency compensation value.
66
67 fsl,tmr-fiper1:
68 $ref: /schemas/types.yaml#/definitions/uint32
69 description: Fixed interval period pulse generator.
70
71 fsl,tmr-fiper2:
72 $ref: /schemas/types.yaml#/definitions/uint32
73 description: Fixed interval period pulse generator.
74
75 fsl,tmr-fiper3:
76 $ref: /schemas/types.yaml#/definitions/uint32
77 description:
78 Fixed interval period pulse generator.
79 Supported only on DPAA2 and ENETC hardware.
80
81 fsl,max-adj:
82 $ref: /schemas/types.yaml#/definitions/uint32
83 description: |
84 Maximum frequency adjustment in parts per billion.
85
86 These properties set the operational parameters for the PTP
87 clock. You must choose these carefully for the clock to work right.
88 Here is how to figure good values:
89
90 TimerOsc = selected reference clock MHz
91 tclk_period = desired clock period nanoseconds
92 NominalFreq = 1000 / tclk_period MHz
93 FreqDivRatio = TimerOsc / NominalFreq (must be greater that 1.0)
94 tmr_add = ceil(2^32 / FreqDivRatio)
95 OutputClock = NominalFreq / tmr_prsc MHz
96 PulseWidth = 1 / OutputClock microseconds
97 FiperFreq1 = desired frequency in Hz
98 FiperDiv1 = 1000000 * OutputClock / FiperFreq1
99 tmr_fiper1 = tmr_prsc * tclk_period * FiperDiv1 - tclk_period
100 max_adj = 1000000000 * (FreqDivRatio - 1.0) - 1
101
102 The calculation for tmr_fiper2 is the same as for tmr_fiper1. The
103 driver expects that tmr_fiper1 will be correctly set to produce a 1
104 Pulse Per Second (PPS) signal, since this will be offered to the PPS
105 subsystem to synchronize the Linux clock.
106
107 When this attribute is not used, the IEEE 1588 timer reference clock
108 will use the eTSEC system clock (for Gianfar) or the MAC system
109 clock (for DPAA).
110
111 fsl,extts-fifo:
112 $ref: /schemas/types.yaml#/definitions/flag
113 description:
114 The presence of this property indicates hardware
115 support for the external trigger stamp FIFO
116
117 little-endian:
118 $ref: /schemas/types.yaml#/definitions/flag
119 description:
120 The presence of this property indicates the 1588 timer
121 support for the external trigger stamp FIFO.
122 IP block is little-endian mode. The default endian mode
123 is big-endian.
124
125required:
126 - compatible
127 - reg
128
129allOf:
130 - if:
131 properties:
132 compatible:
133 contains:
134 const: fsl,enetc-ptp
135 then:
136 $ref: /schemas/pci/pci-device.yaml
137
138additionalProperties: false
139
140examples:
141 - |
142 #include <dt-bindings/interrupt-controller/irq.h>
143
144 phc@24e00 {
145 compatible = "fsl,etsec-ptp";
146 reg = <0x24e00 0xb0>;
147 interrupts = <12 IRQ_TYPE_LEVEL_LOW>;
148 interrupt-parent = <&ipic>;
149 fsl,cksel = <1>;
150 fsl,tclk-period = <10>;
151 fsl,tmr-prsc = <100>;
152 fsl,tmr-add = <0x999999a4>;
153 fsl,tmr-fiper1 = <0x3b9ac9f6>;
154 fsl,tmr-fiper2 = <0x00018696>;
155 fsl,max-adj = <659999998>;
156 };