Re: [PATCH v6] clk: add CS2000 Fractional-N driver

[Kuninori Morimoto]

Hi

ping ?

> 
> From: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>
> 
> This patch adds CS2000 Fractional-N driver as clock provider.
> 
> Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>
> ---
> v5 -> v6
> 
>  - remove redundant variable from each functions
>  - multi line code become one line
>  - end of comment has dot
>  - cs2000_wait_pll_lock() returns -ETIMEDOUT instead of -EIO
>  - removed explicit casting from ratio function
>  - removed magic number
> 
>  .../devicetree/bindings/clock/cs2000-cp.txt        |  22 +
>  drivers/clk/Kconfig                                |   6 +
>  drivers/clk/Makefile                               |   1 +
>  drivers/clk/clk-cs2000-cp.c                        | 509 +++++++++++++++++++++
>  4 files changed, 538 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/clock/cs2000-cp.txt
>  create mode 100644 drivers/clk/clk-cs2000-cp.c
> 
> diff --git a/Documentation/devicetree/bindings/clock/cs2000-cp.txt b/Documentation/devicetree/bindings/clock/cs2000-cp.txt
> new file mode 100644
> index 0000000..54e6df0
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/cs2000-cp.txt
> @@ -0,0 +1,22 @@
> +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";
> +	};
> +};
> diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
> index a1fa611..b8c347f 100644
> --- a/drivers/clk/Kconfig
> +++ b/drivers/clk/Kconfig
> @@ -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
> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
> index 366350a..86afe50 100644
> --- a/drivers/clk/Makefile
> +++ b/drivers/clk/Makefile
> @@ -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
> diff --git a/drivers/clk/clk-cs2000-cp.c b/drivers/clk/clk-cs2000-cp.c
> new file mode 100644
> index 0000000..cc90d87
> --- /dev/null
> +++ b/drivers/clk/clk-cs2000-cp.c
> @@ -0,0 +1,509 @@
> +/*
> + * CS2000  --  CIRRUS LOGIC Fractional-N Clock Synthesizer & Clock Multiplier
> + *
> + * Copyright (C) 2015 Renesas Electronics Corporation
> + * Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>
> + *
> + * 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)
> +{
> +	u32 tmp, 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@xxxxxxxxxxx>");
> +MODULE_LICENSE("GPL v2");
> -- 
> 1.9.1
> 
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