1 Binding for Silicon Labs Si5340, Si5341 Si5342, Si5344 and Si5345 programmable
2 i2c clock generator.
3
4 Reference
5 [1] Si5341 Data Sheet
6 https://www.silabs.com/documents/public/data-sheets/Si5341-40-D-DataSheet.pdf
7 [2] Si5341 Reference Manual
8 https://www.silabs.com/documents/public/reference-manuals/Si5341-40-D-RM.pdf
9 [3] Si5345 Reference Manual
10 https://www.silabs.com/documents/public/reference-manuals/Si5345-44-42-D-RM.pdf
11
12 The Si5341 and Si5340 are programmable i2c clock generators with up to 10 output
13 clocks. The chip contains a PLL that sources 5 (or 4) multisynth clocks, which
14 in turn can be directed to any of the 10 (or 4) outputs through a divider.
15 The internal structure of the clock generators can be found in [2].
16 The Si5345 is similar to the Si5341 with the addition of fractional input
17 dividers and automatic input selection, as described in [3].
18 The Si5342 and Si5344 are smaller versions of the Si5345, with 2 or 4 outputs.
19
20 The driver can be used in "as is" mode, reading the current settings from the
21 chip at boot, in case you have a (pre-)programmed device. If the PLL is not
22 configured when the driver probes, it assumes the driver must fully initialize
23 it.
24
25 The device type, speed grade and revision are determined runtime by probing.
26
27 The driver currently does not support any fancy input configurations. They can
28 still be programmed into the chip and the driver will leave them "as is".
29
30 ==I2C device node==
31
32 Required properties:
33 - compatible: shall be one of the following:
34 "silabs,si5340" - Si5340 A/B/C/D
35 "silabs,si5341" - Si5341 A/B/C/D
36 "silabs,si5342" - Si5342 A/B/C/D
37 "silabs,si5344" - Si5344 A/B/C/D
38 "silabs,si5345" - Si5345 A/B/C/D
39 - reg: i2c device address, usually 0x74
40 - #clock-cells: from common clock binding; shall be set to 2.
41 The first value is "0" for outputs, "1" for synthesizers.
42 The second value is the output or synthesizer index.
43 - clocks: from common clock binding; list of parent clock handles,
44 corresponding to inputs. Use a fixed clock for the "xtal" input.
45 At least one must be present.
46 - clock-names: One of: "xtal", "in0", "in1", "in2"
47
48 Optional properties:
49 - vdd-supply: Regulator node for VDD
50 - vdda-supply: Regulator node for VDDA
51 - vdds-supply: Regulator node for VDDS
52 - silabs,pll-m-num, silabs,pll-m-den: Numerator and denominator for PLL
53 feedback divider. Must be such that the PLL output is in the valid range. For
54 example, to create 14GHz from a 48MHz xtal, use m-num=14000 and m-den=48. Only
55 the fraction matters, using 3500 and 12 will deliver the exact same result.
56 If these are not specified, and the PLL is not yet programmed when the driver
57 probes, the PLL will be set to 14GHz.
58 - silabs,reprogram: When present, the driver will always assume the device must
59 be initialized, and always performs the soft-reset routine. Since this will
60 temporarily stop all output clocks, don't do this if the chip is generating
61 the CPU clock for example.
62 - silabs,xaxb-ext-clk: When present, indicates that the XA/XB pins are used
63 in EXTCLK (external reference clock) rather than XTAL (crystal) mode.
64 - interrupts: Interrupt for INTRb pin.
65 - silabs,iovdd-33: When present, indicates that the I2C lines are using 3.3V
66 rather than 1.8V thresholds.
67 - vddoX-supply (where X is an output index): Regulator node for VDDO for the
68 specified output. The driver selects the output VDD_SEL setting based on this
69 voltage.
70 - #address-cells: shall be set to 1.
71 - #size-cells: shall be set to 0.
72
73
74 == Child nodes: Outputs ==
75
76 The child nodes list the output clocks.
77
78 Each of the clock outputs can be overwritten individually by using a child node.
79 If a child node for a clock output is not set, the configuration remains
80 unchanged.
81
82 Required child node properties:
83 - reg: number of clock output.
84
85 Optional child node properties:
86 - silabs,format: Output format, one of:
87 1 = differential (defaults to LVDS levels)
88 2 = low-power (defaults to HCSL levels)
89 4 = LVCMOS
90 - silabs,common-mode: Manually override output common mode, see [2] for values
91 - silabs,amplitude: Manually override output amplitude, see [2] for values
92 - silabs,synth-master: boolean. If present, this output is allowed to change the
93 multisynth frequency dynamically.
94 - silabs,silabs,disable-high: boolean. If set, the clock output is driven HIGH
95 when disabled, otherwise it's driven LOW.
96
97 ==Example==
98
99 /* 48MHz reference crystal */
100 ref48: ref48M {
101 compatible = "fixed-clock";
102 #clock-cells = <0>;
103 clock-frequency = <48000000>;
104 };
105
106 i2c-master-node {
107 /* Programmable clock (for logic) */
108 si5341: clock-generator@74 {
109 reg = <0x74>;
110 compatible = "silabs,si5341";
111 #clock-cells = <2>;
112 #address-cells = <1>;
113 #size-cells = <0>;
114 clocks = <&ref48>;
115 clock-names = "xtal";
116
117 silabs,pll-m-num = <14000>; /* PLL at 14.0 GHz */
118 silabs,pll-m-den = <48>;
119 silabs,reprogram; /* Chips are not programmed, always reset */
120
121 out@0 {
122 reg = <0>;
123 silabs,format = <1>; /* LVDS 3v3 */
124 silabs,common-mode = <3>;
125 silabs,amplitude = <3>;
126 silabs,synth-master;
127 };
128
129 /*
130 * Output 6 configuration:
131 * LVDS 1v8
132 */
133 out@6 {
134 reg = <6>;
135 silabs,format = <1>; /* LVDS 1v8 */
136 silabs,common-mode = <13>;
137 silabs,amplitude = <3>;
138 };
139
140 /*
141 * Output 8 configuration:
142 * HCSL 3v3
143 */
144 out@8 {
145 reg = <8>;
146 silabs,format = <2>;
147 silabs,common-mode = <11>;
148 silabs,amplitude = <3>;
149 };
150 };
151 };
152
153 some-video-node {
154 /* Standard clock bindings */
155 clock-names = "pixel";
156 clocks = <&si5341 0 7>; /* Output 7 */
157
158 /* Set output 7 to use syntesizer 3 as its parent */
159 assigned-clocks = <&si5341 0 7>, <&si5341 1 3>;
160 assigned-clock-parents = <&si5341 1 3>;
161 /* Set output 7 to 148.5 MHz using a synth frequency of 594 MHz */
162 assigned-clock-rates = <148500000>, <594000000>;
163 };
164
165 some-audio-node {
166 clock-names = "i2s-clk";
167 clocks = <&si5341 0 0>;
168 /*
169 * since output 0 is a synth-master, the synth will be automatically set
170 * to an appropriate frequency when the audio driver requests another
171 * frequency. We give control over synth 2 to this output here.
172 */
173 assigned-clocks = <&si5341 0 0>;
174 assigned-clock-parents = <&si5341 1 2>;
175 };
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