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Binding for Silicon Labs Si5351a/b/c programmable i2c clock generator.
Reference
[1] Si5351A/B/C Data Sheet
http://www.silabs.com/Support%20Documents/TechnicalDocs/Si5351.pdf
The Si5351a/b/c are programmable i2c clock generators with upto 8 output
clocks. Si5351a also has a reduced pin-count package (MSOP10) where only
3 output clocks are accessible. The internal structure of the clock
generators can be found in [1].
==I2C device node==
Required properties:
- compatible: shall be one of "silabs,si5351{a,a-msop,b,c}".
- reg: i2c device address, shall be 0x60 or 0x61.
- #clock-cells: from common clock binding; shall be set to 1.
- clocks: from common clock binding; list of parent clock
handles, shall be xtal reference clock or xtal and clkin for
si5351c only.
- #address-cells: shall be set to 1.
- #size-cells: shall be set to 0.
Optional properties:
- silabs,pll-source: pair of (number, source) for each pll. Allows
to overwrite clock source of pll A (number=0) or B (number=1).
==Child nodes==
Each of the clock outputs can be overwritten individually by
using a child node to the I2C device node. If a child node for a clock
output is not set, the eeprom configuration is not overwritten.
Required child node properties:
- reg: number of clock output.
Optional child node properties:
- silabs,clock-source: source clock of the output divider stage N, shall be
0 = multisynth N
1 = multisynth 0 for output clocks 0-3, else multisynth4
2 = xtal
3 = clkin (si5351c only)
- silabs,drive-strength: output drive strength in mA, shall be one of {2,4,6,8}.
- silabs,multisynth-source: source pll A(0) or B(1) of corresponding multisynth
divider.
- silabs,pll-master: boolean, multisynth can change pll frequency.
- silabs,disable-state : clock output disable state, shall be
0 = clock output is driven LOW when disabled
1 = clock output is driven HIGH when disabled
2 = clock output is FLOATING (HIGH-Z) when disabled
3 = clock output is NEVER disabled
==Example==
/* 25MHz reference crystal */
ref25: ref25M {
compatible = "fixed-clock";
#clock-cells = <0>;
clock-frequency = <25000000>;
};
i2c-master-node {
/* Si5351a msop10 i2c clock generator */
si5351a: clock-generator@60 {
compatible = "silabs,si5351a-msop";
reg = <0x60>;
#address-cells = <1>;
#size-cells = <0>;
#clock-cells = <1>;
/* connect xtal input to 25MHz reference */
clocks = <&ref25>;
/* connect xtal input as source of pll0 and pll1 */
silabs,pll-source = <0 0>, <1 0>;
/*
* overwrite clkout0 configuration with:
* - 8mA output drive strength
* - pll0 as clock source of multisynth0
* - multisynth0 as clock source of output divider
* - multisynth0 can change pll0
* - set initial clock frequency of 74.25MHz
*/
clkout0 {
reg = <0>;
silabs,drive-strength = <8>;
silabs,multisynth-source = <0>;
silabs,clock-source = <0>;
silabs,pll-master;
clock-frequency = <74250000>;
};
/*
* overwrite clkout1 configuration with:
* - 4mA output drive strength
* - pll1 as clock source of multisynth1
* - multisynth1 as clock source of output divider
* - multisynth1 can change pll1
*/
clkout1 {
reg = <1>;
silabs,drive-strength = <4>;
silabs,multisynth-source = <1>;
silabs,clock-source = <0>;
pll-master;
};
/*
* overwrite clkout2 configuration with:
* - xtal as clock source of output divider
*/
clkout2 {
reg = <2>;
silabs,clock-source = <2>;
};
};
};
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