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diff --git a/Documentation/devicetree/bindings/clock/silabs,si5341.txt b/Documentation/devicetree/bindings/clock/silabs,si5341.txt new file mode 100644 index 000000000..ce55aba0c --- /dev/null +++ b/Documentation/devicetree/bindings/clock/silabs,si5341.txt @@ -0,0 +1,175 @@ +Binding for Silicon Labs Si5340, Si5341 Si5342, Si5344 and Si5345 programmable +i2c clock generator. + +Reference +[1] Si5341 Data Sheet + https://www.silabs.com/documents/public/data-sheets/Si5341-40-D-DataSheet.pdf +[2] Si5341 Reference Manual + https://www.silabs.com/documents/public/reference-manuals/Si5341-40-D-RM.pdf +[3] Si5345 Reference Manual + https://www.silabs.com/documents/public/reference-manuals/Si5345-44-42-D-RM.pdf + +The Si5341 and Si5340 are programmable i2c clock generators with up to 10 output +clocks. The chip contains a PLL that sources 5 (or 4) multisynth clocks, which +in turn can be directed to any of the 10 (or 4) outputs through a divider. +The internal structure of the clock generators can be found in [2]. +The Si5345 is similar to the Si5341 with the addition of fractional input +dividers and automatic input selection, as described in [3]. +The Si5342 and Si5344 are smaller versions of the Si5345, with 2 or 4 outputs. + +The driver can be used in "as is" mode, reading the current settings from the +chip at boot, in case you have a (pre-)programmed device. If the PLL is not +configured when the driver probes, it assumes the driver must fully initialize +it. + +The device type, speed grade and revision are determined runtime by probing. + +The driver currently does not support any fancy input configurations. They can +still be programmed into the chip and the driver will leave them "as is". + +==I2C device node== + +Required properties: +- compatible: shall be one of the following: + "silabs,si5340" - Si5340 A/B/C/D + "silabs,si5341" - Si5341 A/B/C/D + "silabs,si5342" - Si5342 A/B/C/D + "silabs,si5344" - Si5344 A/B/C/D + "silabs,si5345" - Si5345 A/B/C/D +- reg: i2c device address, usually 0x74 +- #clock-cells: from common clock binding; shall be set to 2. + The first value is "0" for outputs, "1" for synthesizers. + The second value is the output or synthesizer index. +- clocks: from common clock binding; list of parent clock handles, + corresponding to inputs. Use a fixed clock for the "xtal" input. + At least one must be present. +- clock-names: One of: "xtal", "in0", "in1", "in2" + +Optional properties: +- vdd-supply: Regulator node for VDD +- vdda-supply: Regulator node for VDDA +- vdds-supply: Regulator node for VDDS +- silabs,pll-m-num, silabs,pll-m-den: Numerator and denominator for PLL + feedback divider. Must be such that the PLL output is in the valid range. For + example, to create 14GHz from a 48MHz xtal, use m-num=14000 and m-den=48. Only + the fraction matters, using 3500 and 12 will deliver the exact same result. + If these are not specified, and the PLL is not yet programmed when the driver + probes, the PLL will be set to 14GHz. +- silabs,reprogram: When present, the driver will always assume the device must + be initialized, and always performs the soft-reset routine. Since this will + temporarily stop all output clocks, don't do this if the chip is generating + the CPU clock for example. +- silabs,xaxb-ext-clk: When present, indicates that the XA/XB pins are used + in EXTCLK (external reference clock) rather than XTAL (crystal) mode. +- interrupts: Interrupt for INTRb pin. +- silabs,iovdd-33: When present, indicates that the I2C lines are using 3.3V + rather than 1.8V thresholds. +- vddoX-supply (where X is an output index): Regulator node for VDDO for the + specified output. The driver selects the output VDD_SEL setting based on this + voltage. +- #address-cells: shall be set to 1. +- #size-cells: shall be set to 0. + + +== Child nodes: Outputs == + +The child nodes list the output clocks. + +Each of the clock outputs can be overwritten individually by using a child node. +If a child node for a clock output is not set, the configuration remains +unchanged. + +Required child node properties: +- reg: number of clock output. + +Optional child node properties: +- silabs,format: Output format, one of: + 1 = differential (defaults to LVDS levels) + 2 = low-power (defaults to HCSL levels) + 4 = LVCMOS +- silabs,common-mode: Manually override output common mode, see [2] for values +- silabs,amplitude: Manually override output amplitude, see [2] for values +- silabs,synth-master: boolean. If present, this output is allowed to change the + multisynth frequency dynamically. +- silabs,silabs,disable-high: boolean. If set, the clock output is driven HIGH + when disabled, otherwise it's driven LOW. + +==Example== + +/* 48MHz reference crystal */ +ref48: ref48M { + compatible = "fixed-clock"; + #clock-cells = <0>; + clock-frequency = <48000000>; +}; + +i2c-master-node { + /* Programmable clock (for logic) */ + si5341: clock-generator@74 { + reg = <0x74>; + compatible = "silabs,si5341"; + #clock-cells = <2>; + #address-cells = <1>; + #size-cells = <0>; + clocks = <&ref48>; + clock-names = "xtal"; + + silabs,pll-m-num = <14000>; /* PLL at 14.0 GHz */ + silabs,pll-m-den = <48>; + silabs,reprogram; /* Chips are not programmed, always reset */ + + out@0 { + reg = <0>; + silabs,format = <1>; /* LVDS 3v3 */ + silabs,common-mode = <3>; + silabs,amplitude = <3>; + silabs,synth-master; + }; + + /* + * Output 6 configuration: + * LVDS 1v8 + */ + out@6 { + reg = <6>; + silabs,format = <1>; /* LVDS 1v8 */ + silabs,common-mode = <13>; + silabs,amplitude = <3>; + }; + + /* + * Output 8 configuration: + * HCSL 3v3 + */ + out@8 { + reg = <8>; + silabs,format = <2>; + silabs,common-mode = <11>; + silabs,amplitude = <3>; + }; + }; +}; + +some-video-node { + /* Standard clock bindings */ + clock-names = "pixel"; + clocks = <&si5341 0 7>; /* Output 7 */ + + /* Set output 7 to use syntesizer 3 as its parent */ + assigned-clocks = <&si5341 0 7>, <&si5341 1 3>; + assigned-clock-parents = <&si5341 1 3>; + /* Set output 7 to 148.5 MHz using a synth frequency of 594 MHz */ + assigned-clock-rates = <148500000>, <594000000>; +}; + +some-audio-node { + clock-names = "i2s-clk"; + clocks = <&si5341 0 0>; + /* + * since output 0 is a synth-master, the synth will be automatically set + * to an appropriate frequency when the audio driver requests another + * frequency. We give control over synth 2 to this output here. + */ + assigned-clocks = <&si5341 0 0>; + assigned-clock-parents = <&si5341 1 2>; +}; |