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diff --git a/Documentation/devicetree/bindings/clock/silabs,si5351.txt b/Documentation/devicetree/bindings/clock/silabs,si5351.txt new file mode 100644 index 000000000..f00191cad --- /dev/null +++ b/Documentation/devicetree/bindings/clock/silabs,si5351.txt @@ -0,0 +1,126 @@ +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 up to 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 the following: + "silabs,si5351a" - Si5351a, QFN20 package + "silabs,si5351a-msop" - Si5351a, MSOP10 package + "silabs,si5351b" - Si5351b, QFN20 package + "silabs,si5351c" - Si5351c, QFN20 package +- 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. Corresponding clock input names are "xtal" and + "clkin" respectively. +- #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,pll-reset: boolean, clock output can reset its pll. +- 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>; + clock-names = "xtal"; + + /* 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>; + }; + }; +}; |