clk: add si5351 i2c common clock driver

This patch adds a common clock driver for Silicon Labs Si5351a/b/c
i2c programmable clock generators. Currently, the driver does not
support VXCO feature of si5351b. Passing platform_data or DT bindings
selectively allows to overwrite stored Si5351 configuration which is
very helpful for clock generators with empty eeprom configuration.
Corresponding device tree binding documentation is also added.
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Tested-by: Daniel Mack <zonque@gmail.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Michal Bachraty <michal.bachraty@streamunlimited.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

Documentation/devicetree/bindings/clock/silabs,si5351.txt

+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>;
+		};
+	};
+};

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -48,6 +48,7 @@ samsung	Samsung Semiconductor
 sbs	Smart Battery System
 schindler	Schindler
 sil	Silicon Image
+silabs	Silicon Laboratories
 simtek
 sirf	SiRF Technology, Inc.
 snps 	Synopsys, Inc.

drivers/clk/Kconfig

@@ -55,6 +55,15 @@ config COMMON_CLK_MAX77686
 	---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

drivers/clk/Makefile

@@ -36,4 +36,5 @@ obj-$(CONFIG_X86)		+= x86/
 obj-$(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

drivers/clk/clk-si5351.h

+/*
+ * clk-si5351.h: Silicon Laboratories Si5351A/B/C I2C Clock Generator
+ *
+ * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
+ * Rabeeh Khoury <rabeeh@solid-run.com>
+ *
+ * This program is free software; you can redistribute  it and/or modify it
+ * under  the terms of  the GNU General  Public License as published by the
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ */
+
+#ifndef _CLK_SI5351_H_
+#define _CLK_SI5351_H_
+
+#define SI5351_BUS_BASE_ADDR			0x60
+
+#define SI5351_PLL_VCO_MIN			600000000
+#define SI5351_PLL_VCO_MAX			900000000
+#define SI5351_MULTISYNTH_MIN_FREQ		1000000
+#define SI5351_MULTISYNTH_DIVBY4_FREQ		150000000
+#define SI5351_MULTISYNTH_MAX_FREQ		160000000
+#define SI5351_MULTISYNTH67_MAX_FREQ		SI5351_MULTISYNTH_DIVBY4_FREQ
+#define SI5351_CLKOUT_MIN_FREQ			8000
+#define SI5351_CLKOUT_MAX_FREQ			SI5351_MULTISYNTH_MAX_FREQ
+#define SI5351_CLKOUT67_MAX_FREQ		SI5351_MULTISYNTH67_MAX_FREQ
+
+#define SI5351_PLL_A_MIN			15
+#define SI5351_PLL_A_MAX			90
+#define SI5351_PLL_B_MAX			(SI5351_PLL_C_MAX-1)
+#define SI5351_PLL_C_MAX			1048575
+#define SI5351_MULTISYNTH_A_MIN			6
+#define SI5351_MULTISYNTH_A_MAX			1800
+#define SI5351_MULTISYNTH67_A_MAX		254
+#define SI5351_MULTISYNTH_B_MAX			(SI5351_MULTISYNTH_C_MAX-1)
+#define SI5351_MULTISYNTH_C_MAX			1048575
+#define SI5351_MULTISYNTH_P1_MAX		((1<<18)-1)
+#define SI5351_MULTISYNTH_P2_MAX		((1<<20)-1)
+#define SI5351_MULTISYNTH_P3_MAX		((1<<20)-1)
+
+#define SI5351_DEVICE_STATUS			0
+#define SI5351_INTERRUPT_STATUS			1
+#define SI5351_INTERRUPT_MASK			2
+#define  SI5351_STATUS_SYS_INIT			(1<<7)
+#define  SI5351_STATUS_LOL_B			(1<<6)
+#define  SI5351_STATUS_LOL_A			(1<<5)
+#define  SI5351_STATUS_LOS			(1<<4)
+#define SI5351_OUTPUT_ENABLE_CTRL		3
+#define SI5351_OEB_PIN_ENABLE_CTRL		9
+#define SI5351_PLL_INPUT_SOURCE			15
+#define  SI5351_CLKIN_DIV_MASK			(3<<6)
+#define  SI5351_CLKIN_DIV_1			(0<<6)
+#define  SI5351_CLKIN_DIV_2			(1<<6)
+#define  SI5351_CLKIN_DIV_4			(2<<6)
+#define  SI5351_CLKIN_DIV_8			(3<<6)
+#define  SI5351_PLLB_SOURCE			(1<<3)
+#define  SI5351_PLLA_SOURCE			(1<<2)
+
+#define SI5351_CLK0_CTRL			16
+#define SI5351_CLK1_CTRL			17
+#define SI5351_CLK2_CTRL			18
+#define SI5351_CLK3_CTRL			19
+#define SI5351_CLK4_CTRL			20
+#define SI5351_CLK5_CTRL			21
+#define SI5351_CLK6_CTRL			22
+#define SI5351_CLK7_CTRL			23
+#define  SI5351_CLK_POWERDOWN			(1<<7)
+#define  SI5351_CLK_INTEGER_MODE		(1<<6)
+#define  SI5351_CLK_PLL_SELECT			(1<<5)
+#define  SI5351_CLK_INVERT			(1<<4)
+#define  SI5351_CLK_INPUT_MASK			(3<<2)
+#define  SI5351_CLK_INPUT_XTAL			(0<<2)
+#define  SI5351_CLK_INPUT_CLKIN			(1<<2)
+#define  SI5351_CLK_INPUT_MULTISYNTH_0_4	(2<<2)
+#define  SI5351_CLK_INPUT_MULTISYNTH_N		(3<<2)
+#define  SI5351_CLK_DRIVE_STRENGTH_MASK		(3<<0)
+#define  SI5351_CLK_DRIVE_STRENGTH_2MA		(0<<0)
+#define  SI5351_CLK_DRIVE_STRENGTH_4MA		(1<<0)
+#define  SI5351_CLK_DRIVE_STRENGTH_6MA		(2<<0)
+#define  SI5351_CLK_DRIVE_STRENGTH_8MA		(3<<0)
+
+#define SI5351_CLK3_0_DISABLE_STATE		24
+#define SI5351_CLK7_4_DISABLE_STATE		25
+#define  SI5351_CLK_DISABLE_STATE_LOW		0
+#define  SI5351_CLK_DISABLE_STATE_HIGH		1
+#define  SI5351_CLK_DISABLE_STATE_FLOAT		2
+#define  SI5351_CLK_DISABLE_STATE_NEVER		3
+
+#define SI5351_PARAMETERS_LENGTH		8
+#define SI5351_PLLA_PARAMETERS			26
+#define SI5351_PLLB_PARAMETERS			34
+#define SI5351_CLK0_PARAMETERS			42
+#define SI5351_CLK1_PARAMETERS			50
+#define SI5351_CLK2_PARAMETERS			58
+#define SI5351_CLK3_PARAMETERS			66
+#define SI5351_CLK4_PARAMETERS			74
+#define SI5351_CLK5_PARAMETERS			82
+#define SI5351_CLK6_PARAMETERS			90
+#define SI5351_CLK7_PARAMETERS			91
+#define SI5351_CLK6_7_OUTPUT_DIVIDER		92
+#define  SI5351_OUTPUT_CLK_DIV_MASK		(7 << 4)
+#define  SI5351_OUTPUT_CLK6_DIV_MASK		(7 << 0)
+#define  SI5351_OUTPUT_CLK_DIV_SHIFT		4
+#define  SI5351_OUTPUT_CLK_DIV6_SHIFT		0
+#define  SI5351_OUTPUT_CLK_DIV_1		0
+#define  SI5351_OUTPUT_CLK_DIV_2		1
+#define  SI5351_OUTPUT_CLK_DIV_4		2
+#define  SI5351_OUTPUT_CLK_DIV_8		3
+#define  SI5351_OUTPUT_CLK_DIV_16		4
+#define  SI5351_OUTPUT_CLK_DIV_32		5
+#define  SI5351_OUTPUT_CLK_DIV_64		6
+#define  SI5351_OUTPUT_CLK_DIV_128		7
+#define  SI5351_OUTPUT_CLK_DIVBY4		(3<<2)
+
+#define SI5351_SSC_PARAM0			149
+#define SI5351_SSC_PARAM1			150
+#define SI5351_SSC_PARAM2			151
+#define SI5351_SSC_PARAM3			152
+#define SI5351_SSC_PARAM4			153
+#define SI5351_SSC_PARAM5			154
+#define SI5351_SSC_PARAM6			155
+#define SI5351_SSC_PARAM7			156
+#define SI5351_SSC_PARAM8			157
+#define SI5351_SSC_PARAM9			158
+#define SI5351_SSC_PARAM10			159
+#define SI5351_SSC_PARAM11			160
+#define SI5351_SSC_PARAM12			161
+
+#define SI5351_VXCO_PARAMETERS_LOW		162
+#define SI5351_VXCO_PARAMETERS_MID		163
+#define SI5351_VXCO_PARAMETERS_HIGH		164
+
+#define SI5351_CLK0_PHASE_OFFSET		165
+#define SI5351_CLK1_PHASE_OFFSET		166
+#define SI5351_CLK2_PHASE_OFFSET		167
+#define SI5351_CLK3_PHASE_OFFSET		168
+#define SI5351_CLK4_PHASE_OFFSET		169
+#define SI5351_CLK5_PHASE_OFFSET		170
+
+#define SI5351_PLL_RESET			177
+#define  SI5351_PLL_RESET_B			(1<<7)
+#define  SI5351_PLL_RESET_A			(1<<5)
+
+#define SI5351_CRYSTAL_LOAD			183
+#define  SI5351_CRYSTAL_LOAD_MASK		(3<<6)
+#define  SI5351_CRYSTAL_LOAD_6PF		(1<<6)
+#define  SI5351_CRYSTAL_LOAD_8PF		(2<<6)
+#define  SI5351_CRYSTAL_LOAD_10PF		(3<<6)
+
+#define SI5351_FANOUT_ENABLE			187
+#define  SI5351_CLKIN_ENABLE			(1<<7)
+#define  SI5351_XTAL_ENABLE			(1<<6)
+#define  SI5351_MULTISYNTH_ENABLE		(1<<4)
+
+#endif

include/linux/platform_data/si5351.h

+/*
+ * Si5351A/B/C programmable clock generator platform_data.
+ */
+
+#ifndef __LINUX_PLATFORM_DATA_SI5351_H__
+#define __LINUX_PLATFORM_DATA_SI5351_H__
+
+struct clk;
+
+/**
+ * enum si5351_variant - SiLabs Si5351 chip variant
+ * @SI5351_VARIANT_A: Si5351A (8 output clocks, XTAL input)
+ * @SI5351_VARIANT_A3: Si5351A MSOP10 (3 output clocks, XTAL input)
+ * @SI5351_VARIANT_B: Si5351B (8 output clocks, XTAL/VXCO input)
+ * @SI5351_VARIANT_C: Si5351C (8 output clocks, XTAL/CLKIN input)
+ */
+enum si5351_variant {
+	SI5351_VARIANT_A = 1,
+	SI5351_VARIANT_A3 = 2,
+	SI5351_VARIANT_B = 3,
+	SI5351_VARIANT_C = 4,
+};
+
+/**
+ * enum si5351_pll_src - Si5351 pll clock source
+ * @SI5351_PLL_SRC_DEFAULT: default, do not change eeprom config
+ * @SI5351_PLL_SRC_XTAL: pll source clock is XTAL input
+ * @SI5351_PLL_SRC_CLKIN: pll source clock is CLKIN input (Si5351C only)
+ */
+enum si5351_pll_src {
+	SI5351_PLL_SRC_DEFAULT = 0,
+	SI5351_PLL_SRC_XTAL = 1,
+	SI5351_PLL_SRC_CLKIN = 2,
+};
+
+/**
+ * enum si5351_multisynth_src - Si5351 multisynth clock source
+ * @SI5351_MULTISYNTH_SRC_DEFAULT: default, do not change eeprom config
+ * @SI5351_MULTISYNTH_SRC_VCO0: multisynth source clock is VCO0
+ * @SI5351_MULTISYNTH_SRC_VCO1: multisynth source clock is VCO1/VXCO
+ */
+enum si5351_multisynth_src {
+	SI5351_MULTISYNTH_SRC_DEFAULT = 0,
+	SI5351_MULTISYNTH_SRC_VCO0 = 1,
+	SI5351_MULTISYNTH_SRC_VCO1 = 2,
+};
+
+/**
+ * enum si5351_clkout_src - Si5351 clock output clock source
+ * @SI5351_CLKOUT_SRC_DEFAULT: default, do not change eeprom config
+ * @SI5351_CLKOUT_SRC_MSYNTH_N: clkout N source clock is multisynth N
+ * @SI5351_CLKOUT_SRC_MSYNTH_0_4: clkout N source clock is multisynth 0 (N<4)
+ *                                or 4 (N>=4)
+ * @SI5351_CLKOUT_SRC_XTAL: clkout N source clock is XTAL
+ * @SI5351_CLKOUT_SRC_CLKIN: clkout N source clock is CLKIN (Si5351C only)
+ */
+enum si5351_clkout_src {
+	SI5351_CLKOUT_SRC_DEFAULT = 0,
+	SI5351_CLKOUT_SRC_MSYNTH_N = 1,
+	SI5351_CLKOUT_SRC_MSYNTH_0_4 = 2,
+	SI5351_CLKOUT_SRC_XTAL = 3,
+	SI5351_CLKOUT_SRC_CLKIN = 4,
+};
+
+/**
+ * enum si5351_drive_strength - Si5351 clock output drive strength
+ * @SI5351_DRIVE_DEFAULT: default, do not change eeprom config
+ * @SI5351_DRIVE_2MA: 2mA clock output drive strength
+ * @SI5351_DRIVE_4MA: 4mA clock output drive strength
+ * @SI5351_DRIVE_6MA: 6mA clock output drive strength
+ * @SI5351_DRIVE_8MA: 8mA clock output drive strength
+ */
+enum si5351_drive_strength {
+	SI5351_DRIVE_DEFAULT = 0,
+	SI5351_DRIVE_2MA = 2,
+	SI5351_DRIVE_4MA = 4,
+	SI5351_DRIVE_6MA = 6,
+	SI5351_DRIVE_8MA = 8,
+};
+
+/**
+ * struct si5351_clkout_config - Si5351 clock output configuration
+ * @clkout: clkout number
+ * @multisynth_src: multisynth source clock
+ * @clkout_src: clkout source clock
+ * @pll_master: if true, clkout can also change pll rate
+ * @drive: output drive strength
+ * @rate: initial clkout rate, or default if 0
+ */
+struct si5351_clkout_config {
+	enum si5351_multisynth_src multisynth_src;
+	enum si5351_clkout_src clkout_src;
+	enum si5351_drive_strength drive;
+	bool pll_master;
+	unsigned long rate;
+};
+
+/**
+ * struct si5351_platform_data - Platform data for the Si5351 clock driver
+ * @variant: Si5351 chip variant
+ * @clk_xtal: xtal input clock
+ * @clk_clkin: clkin input clock
+ * @pll_src: array of pll source clock setting
+ * @clkout: array of clkout configuration
+ */
+struct si5351_platform_data {
+	enum si5351_variant variant;
+	struct clk *clk_xtal;
+	struct clk *clk_clkin;
+	enum si5351_pll_src pll_src[2];
+	struct si5351_clkout_config clkout[8];
+};
+
+#endif