clk: add si5351 i2c common clock driver

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.

==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>;

		};

	};

};

sbs	Smart Battery System

schindler	Schindler

sil	Silicon Image

silabs	Silicon Laboratories

simtek

sirf	SiRF Technology, Inc.

snps 	Synopsys, Inc.

	---help---

	  This driver supports Maxim 77686 crystal oscillator clock. 

config COMMON_CLK_SI5351

	tristate "Clock driver for SiLabs 5351A/B/C"

	depends on I2C

	select REGMAP_I2C

	select RATIONAL

	---help---

	  This driver supports Silicon Labs 5351A/B/C programmable clock

	  generators.

config CLK_TWL6040

	tristate "External McPDM functional clock from twl6040"

	depends on TWL6040_CORE

obj-$(CONFIG_COMMON_CLK_AXI_CLKGEN) += clk-axi-clkgen.o

obj-$(CONFIG_COMMON_CLK_WM831X) += clk-wm831x.o

obj-$(CONFIG_COMMON_CLK_MAX77686) += clk-max77686.o

obj-$(CONFIG_COMMON_CLK_SI5351) += clk-si5351.o

obj-$(CONFIG_CLK_TWL6040)	+= clk-twl6040.o