Commit 64dfbe24 authored by Kuninori Morimoto's avatar Kuninori Morimoto Committed by Stephen Boyd
Browse files

clk: add CS2000 Fractional-N driver 



This patch adds CS2000 Fractional-N driver as clock provider.

Signed-off-by: default avatarKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
[sboyd@codeaurora.org: Fix unsigned checked for < 0 in
cs2000_ratio_get()]
Signed-off-by: default avatarStephen Boyd <sboyd@codeaurora.org>
parent 198bb594

Documentation/devicetree/bindings/clock/cs2000-cp.txt

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CIRRUS LOGIC Fractional-N Clock Synthesizer & Clock Multiplier



Required properties:



- compatible:		"cirrus,cs2000-cp"

- reg:			The chip select number on the I2C bus

- clocks:		common clock binding for CLK_IN, XTI/REF_CLK

- clock-names:		CLK_IN : clk_in, XTI/REF_CLK : ref_clk

- #clock-cells:		must be <0>



Example:



&i2c2 {

	...

	cs2000: clk_multiplier@4f {

		#clock-cells = <0>;

		compatible = "cirrus,cs2000-cp";

		reg = <0x4f>;

		clocks = <&rcar_sound 0>, <&x12_clk>;

		clock-names = "clk_in", "ref_clk";

	};

};

drivers/clk/Kconfig

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@@ -116,6 +116,12 @@ config COMMON_CLK_CDCE925 
	  Given a target output frequency, the driver will set the PLL and

	  divider to best approximate the desired output.



config COMMON_CLK_CS2000_CP

	tristate "Clock driver for CS2000 Fractional-N Clock Synthesizer & Clock Multiplier"

	depends on I2C

	help

	  If you say yes here you get support for the CS2000 clock multiplier.



config COMMON_CLK_S2MPS11

	tristate "Clock driver for S2MPS1X/S5M8767 MFD"

	depends on MFD_SEC_CORE

drivers/clk/Makefile

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@@ -21,6 +21,7 @@ obj-$(CONFIG_MACH_ASM9260) += clk-asm9260.o 
obj-$(CONFIG_COMMON_CLK_AXI_CLKGEN)	+= clk-axi-clkgen.o

obj-$(CONFIG_ARCH_AXXIA)		+= clk-axm5516.o

obj-$(CONFIG_COMMON_CLK_CDCE706)	+= clk-cdce706.o

obj-$(CONFIG_COMMON_CLK_CS2000_CP)	+= clk-cs2000-cp.o

obj-$(CONFIG_ARCH_CLPS711X)		+= clk-clps711x.o

obj-$(CONFIG_ARCH_EFM32)		+= clk-efm32gg.o

obj-$(CONFIG_ARCH_HIGHBANK)		+= clk-highbank.o

drivers/clk/clk-cs2000-cp.c

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/*

 * CS2000  --  CIRRUS LOGIC Fractional-N Clock Synthesizer & Clock Multiplier

 *

 * Copyright (C) 2015 Renesas Electronics Corporation

 * Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 */

#include <linux/clk-provider.h>

#include <linux/delay.h>

#include <linux/clk.h>

#include <linux/i2c.h>

#include <linux/of_device.h>

#include <linux/module.h>



#define CH_MAX 4

#define RATIO_REG_SIZE 4



#define DEVICE_ID	0x1

#define DEVICE_CTRL	0x2

#define DEVICE_CFG1	0x3

#define DEVICE_CFG2	0x4

#define GLOBAL_CFG	0x5

#define Ratio_Add(x, nth)	(6 + (x * 4) + (nth))

#define Ratio_Val(x, nth)	((x >> (24 - (8 * nth))) & 0xFF)

#define Val_Ratio(x, nth)	((x & 0xFF) << (24 - (8 * nth)))

#define FUNC_CFG1	0x16

#define FUNC_CFG2	0x17



/* DEVICE_ID */

#define REVISION_MASK	(0x7)

#define REVISION_B2_B3	(0x4)

#define REVISION_C1	(0x6)



/* DEVICE_CTRL */

#define PLL_UNLOCK	(1 << 7)



/* DEVICE_CFG1 */

#define RSEL(x)		(((x) & 0x3) << 3)

#define RSEL_MASK	RSEL(0x3)

#define ENDEV1		(0x1)



/* GLOBAL_CFG */

#define ENDEV2		(0x1)



#define CH_SIZE_ERR(ch)		((ch < 0) || (ch >= CH_MAX))

#define hw_to_priv(_hw)		container_of(_hw, struct cs2000_priv, hw)

#define priv_to_client(priv)	(priv->client)

#define priv_to_dev(priv)	(&(priv_to_client(priv)->dev))



#define CLK_IN	0

#define REF_CLK	1

#define CLK_MAX 2



struct cs2000_priv {

	struct clk_hw hw;

	struct i2c_client *client;

	struct clk *clk_in;

	struct clk *ref_clk;

	struct clk *clk_out;

};



static const struct of_device_id cs2000_of_match[] = {

	{ .compatible = "cirrus,cs2000-cp", },

	{},

};

MODULE_DEVICE_TABLE(of, cs2000_of_match);



static const struct i2c_device_id cs2000_id[] = {

	{ "cs2000-cp", },

	{}

};

MODULE_DEVICE_TABLE(i2c, cs2000_id);



#define cs2000_read(priv, addr) \

	i2c_smbus_read_byte_data(priv_to_client(priv), addr)

#define cs2000_write(priv, addr, val) \

	i2c_smbus_write_byte_data(priv_to_client(priv), addr, val)



static int cs2000_bset(struct cs2000_priv *priv, u8 addr, u8 mask, u8 val)

{

	s32 data;



	data = cs2000_read(priv, addr);

	if (data < 0)

		return data;



	data &= ~mask;

	data |= (val & mask);



	return cs2000_write(priv, addr, data);

}



static int cs2000_enable_dev_config(struct cs2000_priv *priv, bool enable)

{

	int ret;



	ret = cs2000_bset(priv, DEVICE_CFG1, ENDEV1,

			  enable ? ENDEV1 : 0);

	if (ret < 0)

		return ret;



	ret = cs2000_bset(priv, GLOBAL_CFG,  ENDEV2,

			  enable ? ENDEV2 : 0);

	if (ret < 0)

		return ret;



	return 0;

}



static int cs2000_clk_in_bound_rate(struct cs2000_priv *priv,

				    u32 rate_in)

{

	u32 val;



	if (rate_in >= 32000000 && rate_in < 56000000)

		val = 0x0;

	else if (rate_in >= 16000000 && rate_in < 28000000)

		val = 0x1;

	else if (rate_in >= 8000000 && rate_in < 14000000)

		val = 0x2;

	else

		return -EINVAL;



	return cs2000_bset(priv, FUNC_CFG1, 0x3 << 3, val << 3);

}



static int cs2000_wait_pll_lock(struct cs2000_priv *priv)

{

	struct device *dev = priv_to_dev(priv);

	s32 val;

	unsigned int i;



	for (i = 0; i < 256; i++) {

		val = cs2000_read(priv, DEVICE_CTRL);

		if (val < 0)

			return val;

		if (!(val & PLL_UNLOCK))

			return 0;

		udelay(1);

	}



	dev_err(dev, "pll lock failed\n");



	return -ETIMEDOUT;

}



static int cs2000_clk_out_enable(struct cs2000_priv *priv, bool enable)

{

	/* enable both AUX_OUT, CLK_OUT */

	return cs2000_write(priv, DEVICE_CTRL, enable ? 0 : 0x3);

}



static u32 cs2000_rate_to_ratio(u32 rate_in, u32 rate_out)

{

	u64 ratio;



	/*

	 * ratio = rate_out / rate_in * 2^20

	 *

	 * To avoid over flow, rate_out is u64.

	 * The result should be u32.

	 */

	ratio = (u64)rate_out << 20;

	do_div(ratio, rate_in);



	return ratio;

}



static unsigned long cs2000_ratio_to_rate(u32 ratio, u32 rate_in)

{

	u64 rate_out;



	/*

	 * ratio = rate_out / rate_in * 2^20

	 *

	 * To avoid over flow, rate_out is u64.

	 * The result should be u32 or unsigned long.

	 */



	rate_out = (u64)ratio * rate_in;

	return rate_out >> 20;

}



static int cs2000_ratio_set(struct cs2000_priv *priv,

			    int ch, u32 rate_in, u32 rate_out)

{

	u32 val;

	unsigned int i;

	int ret;



	if (CH_SIZE_ERR(ch))

		return -EINVAL;



	val = cs2000_rate_to_ratio(rate_in, rate_out);

	for (i = 0; i < RATIO_REG_SIZE; i++) {

		ret = cs2000_write(priv,

				   Ratio_Add(ch, i),

				   Ratio_Val(val, i));

		if (ret < 0)

			return ret;

	}



	return 0;

}



static u32 cs2000_ratio_get(struct cs2000_priv *priv, int ch)

{

	s32 tmp;

	u32 val;

	unsigned int i;



	val = 0;

	for (i = 0; i < RATIO_REG_SIZE; i++) {

		tmp = cs2000_read(priv, Ratio_Add(ch, i));

		if (tmp < 0)

			return 0;



		val |= Val_Ratio(tmp, i);

	}



	return val;

}



static int cs2000_ratio_select(struct cs2000_priv *priv, int ch)

{

	int ret;



	if (CH_SIZE_ERR(ch))

		return -EINVAL;



	/*

	 * FIXME

	 *

	 * this driver supports static ratio mode only at this point.

	 */

	ret = cs2000_bset(priv, DEVICE_CFG1, RSEL_MASK, RSEL(ch));

	if (ret < 0)

		return ret;



	ret = cs2000_write(priv, DEVICE_CFG2, 0x0);

	if (ret < 0)

		return ret;



	return 0;

}



static unsigned long cs2000_recalc_rate(struct clk_hw *hw,

					unsigned long parent_rate)

{

	struct cs2000_priv *priv = hw_to_priv(hw);

	int ch = 0; /* it uses ch0 only at this point */

	u32 ratio;



	ratio = cs2000_ratio_get(priv, ch);



	return cs2000_ratio_to_rate(ratio, parent_rate);

}



static long cs2000_round_rate(struct clk_hw *hw, unsigned long rate,

			      unsigned long *parent_rate)

{

	u32 ratio;



	ratio = cs2000_rate_to_ratio(*parent_rate, rate);



	return cs2000_ratio_to_rate(ratio, *parent_rate);

}



static int __cs2000_set_rate(struct cs2000_priv *priv, int ch,

			     unsigned long rate, unsigned long parent_rate)



{

	int ret;



	ret = cs2000_clk_in_bound_rate(priv, parent_rate);

	if (ret < 0)

		return ret;



	ret = cs2000_ratio_set(priv, ch, parent_rate, rate);

	if (ret < 0)

		return ret;



	ret = cs2000_ratio_select(priv, ch);

	if (ret < 0)

		return ret;



	return 0;

}



static int cs2000_set_rate(struct clk_hw *hw,

			   unsigned long rate, unsigned long parent_rate)

{

	struct cs2000_priv *priv = hw_to_priv(hw);

	int ch = 0; /* it uses ch0 only at this point */



	return __cs2000_set_rate(priv, ch, rate, parent_rate);

}



static int cs2000_enable(struct clk_hw *hw)

{

	struct cs2000_priv *priv = hw_to_priv(hw);

	int ret;



	ret = cs2000_enable_dev_config(priv, true);

	if (ret < 0)

		return ret;



	ret = cs2000_clk_out_enable(priv, true);

	if (ret < 0)

		return ret;



	ret = cs2000_wait_pll_lock(priv);

	if (ret < 0)

		return ret;



	return ret;

}



static void cs2000_disable(struct clk_hw *hw)

{

	struct cs2000_priv *priv = hw_to_priv(hw);



	cs2000_enable_dev_config(priv, false);



	cs2000_clk_out_enable(priv, false);

}



static u8 cs2000_get_parent(struct clk_hw *hw)

{

	/* always return REF_CLK */

	return REF_CLK;

}



static const struct clk_ops cs2000_ops = {

	.get_parent	= cs2000_get_parent,

	.recalc_rate	= cs2000_recalc_rate,

	.round_rate	= cs2000_round_rate,

	.set_rate	= cs2000_set_rate,

	.prepare	= cs2000_enable,

	.unprepare	= cs2000_disable,

};



static int cs2000_clk_get(struct cs2000_priv *priv)

{

	struct i2c_client *client = priv_to_client(priv);

	struct device *dev = &client->dev;

	struct clk *clk_in, *ref_clk;



	clk_in = devm_clk_get(dev, "clk_in");

	/* not yet provided */

	if (IS_ERR(clk_in))

		return -EPROBE_DEFER;



	ref_clk = devm_clk_get(dev, "ref_clk");

	/* not yet provided */

	if (IS_ERR(ref_clk))

		return -EPROBE_DEFER;



	priv->clk_in	= clk_in;

	priv->ref_clk	= ref_clk;



	return 0;

}



static int cs2000_clk_register(struct cs2000_priv *priv)

{

	struct device *dev = priv_to_dev(priv);

	struct device_node *np = dev->of_node;

	struct clk_init_data init;

	const char *name = np->name;

	struct clk *clk;

	static const char *parent_names[CLK_MAX];

	int ch = 0; /* it uses ch0 only at this point */

	int rate;

	int ret;



	of_property_read_string(np, "clock-output-names", &name);



	/*

	 * set default rate as 1/1.

	 * otherwise .set_rate which setup ratio

	 * is never called if user requests 1/1 rate

	 */

	rate = clk_get_rate(priv->ref_clk);

	ret = __cs2000_set_rate(priv, ch, rate, rate);

	if (ret < 0)

		return ret;



	parent_names[CLK_IN]	= __clk_get_name(priv->clk_in);

	parent_names[REF_CLK]	= __clk_get_name(priv->ref_clk);



	init.name		= name;

	init.ops		= &cs2000_ops;

	init.flags		= CLK_SET_RATE_GATE;

	init.parent_names	= parent_names;

	init.num_parents	= ARRAY_SIZE(parent_names);



	priv->hw.init = &init;



	clk = clk_register(dev, &priv->hw);

	if (IS_ERR(clk))

		return PTR_ERR(clk);



	ret = of_clk_add_provider(np, of_clk_src_simple_get, clk);

	if (ret < 0) {

		clk_unregister(clk);

		return ret;

	}



	priv->clk_out = clk;



	return 0;

}



static int cs2000_version_print(struct cs2000_priv *priv)

{

	struct i2c_client *client = priv_to_client(priv);

	struct device *dev = &client->dev;

	s32 val;

	const char *revision;



	val = cs2000_read(priv, DEVICE_ID);

	if (val < 0)

		return val;



	/* CS2000 should be 0x0 */

	if (val >> 3)

		return -EIO;



	switch (val & REVISION_MASK) {

	case REVISION_B2_B3:

		revision = "B2 / B3";

		break;

	case REVISION_C1:

		revision = "C1";

		break;

	default:

		return -EIO;

	}



	dev_info(dev, "revision - %s\n", revision);



	return 0;

}



static int cs2000_remove(struct i2c_client *client)

{

	struct cs2000_priv *priv = i2c_get_clientdata(client);

	struct device *dev = &client->dev;

	struct device_node *np = dev->of_node;



	of_clk_del_provider(np);



	clk_unregister(priv->clk_out);



	return 0;

}



static int cs2000_probe(struct i2c_client *client,

			const struct i2c_device_id *id)

{

	struct cs2000_priv *priv;

	struct device *dev = &client->dev;

	int ret;



	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);

	if (!priv)

		return -ENOMEM;



	priv->client = client;

	i2c_set_clientdata(client, priv);



	ret = cs2000_clk_get(priv);

	if (ret < 0)

		return ret;



	ret = cs2000_clk_register(priv);

	if (ret < 0)

		return ret;



	ret = cs2000_version_print(priv);

	if (ret < 0)

		goto probe_err;



	return 0;



probe_err:

	cs2000_remove(client);



	return ret;

}



static struct i2c_driver cs2000_driver = {

	.driver = {

		.name = "cs2000-cp",

		.of_match_table = cs2000_of_match,

	},

	.probe		= cs2000_probe,

	.remove		= cs2000_remove,

	.id_table	= cs2000_id,

};



module_i2c_driver(cs2000_driver);



MODULE_DESCRIPTION("CS2000-CP driver");

MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");

MODULE_LICENSE("GPL v2");

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