linux/drivers/clk/clk-cdce706.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * TI CDCE706 programmable 3-PLL clock synthesizer driver
 *
 * Copyright (c) 2014 Cadence Design Systems Inc.
 *
 * Reference: https://www.ti.com/lit/ds/symlink/cdce706.pdf
 */

#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/rational.h>
#include <linux/regmap.h>
#include <linux/slab.h>

#define CDCE706_CLKIN_CLOCK		10
#define CDCE706_CLKIN_SOURCE		11
#define CDCE706_PLL_M_LOW(pll)		(1 + 3 * (pll))
#define CDCE706_PLL_N_LOW(pll)		(2 + 3 * (pll))
#define CDCE706_PLL_HI(pll)		(3 + 3 * (pll))
#define CDCE706_PLL_MUX			3
#define CDCE706_PLL_FVCO		6
#define CDCE706_DIVIDER(div)		(13 + (div))
#define CDCE706_CLKOUT(out)		(19 + (out))

#define CDCE706_CLKIN_CLOCK_MASK	0x10
#define CDCE706_CLKIN_SOURCE_SHIFT	6
#define CDCE706_CLKIN_SOURCE_MASK	0xc0
#define CDCE706_CLKIN_SOURCE_LVCMOS	0x40

#define CDCE706_PLL_MUX_MASK(pll)	(0x80 >> (pll))
#define CDCE706_PLL_LOW_M_MASK		0xff
#define CDCE706_PLL_LOW_N_MASK		0xff
#define CDCE706_PLL_HI_M_MASK		0x1
#define CDCE706_PLL_HI_N_MASK		0x1e
#define CDCE706_PLL_HI_N_SHIFT		1
#define CDCE706_PLL_M_MAX		0x1ff
#define CDCE706_PLL_N_MAX		0xfff
#define CDCE706_PLL_FVCO_MASK(pll)	(0x80 >> (pll))
#define CDCE706_PLL_FREQ_MIN		 80000000
#define CDCE706_PLL_FREQ_MAX		300000000
#define CDCE706_PLL_FREQ_HI		180000000

#define CDCE706_DIVIDER_PLL(div)	(9 + (div) - ((div) > 2) - ((div) > 4))
#define CDCE706_DIVIDER_PLL_SHIFT(div)	((div) < 2 ? 5 : 3 * ((div) & 1))
#define CDCE706_DIVIDER_PLL_MASK(div)	(0x7 << CDCE706_DIVIDER_PLL_SHIFT(div))
#define CDCE706_DIVIDER_DIVIDER_MASK	0x7f
#define CDCE706_DIVIDER_DIVIDER_MAX	0x7f

#define CDCE706_CLKOUT_DIVIDER_MASK	0x7
#define CDCE706_CLKOUT_ENABLE_MASK	0x8

static const struct regmap_config cdce706_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.val_format_endian = REGMAP_ENDIAN_NATIVE,
};

#define to_hw_data(phw) (container_of((phw), struct cdce706_hw_data, hw))

struct cdce706_hw_data {
	struct cdce706_dev_data *dev_data;
	unsigned idx;
	unsigned parent;
	struct clk_hw hw;
	unsigned div;
	unsigned mul;
	unsigned mux;
};

struct cdce706_dev_data {
	struct i2c_client *client;
	struct regmap *regmap;
	struct clk *clkin_clk[2];
	const char *clkin_name[2];
	struct cdce706_hw_data clkin[1];
	struct cdce706_hw_data pll[3];
	struct cdce706_hw_data divider[6];
	struct cdce706_hw_data clkout[6];
};

static const char * const cdce706_source_name[] = {
	"clk_in0", "clk_in1",
};

static const char * const cdce706_clkin_name[] = {
	"clk_in",
};

static const char * const cdce706_pll_name[] = {
	"pll1", "pll2", "pll3",
};

static const char * const cdce706_divider_parent_name[] = {
	"clk_in", "pll1", "pll2", "pll2", "pll3",
};

static const char *cdce706_divider_name[] = {
	"p0", "p1", "p2", "p3", "p4", "p5",
};

static const char * const cdce706_clkout_name[] = {
	"clk_out0", "clk_out1", "clk_out2", "clk_out3", "clk_out4", "clk_out5",
};

static int cdce706_reg_read(struct cdce706_dev_data *dev_data, unsigned reg,
			    unsigned *val)
{
	int rc = regmap_read(dev_data->regmap, reg | 0x80, val);

	if (rc < 0)
		dev_err(&dev_data->client->dev, "error reading reg %u", reg);
	return rc;
}

static int cdce706_reg_write(struct cdce706_dev_data *dev_data, unsigned reg,
			     unsigned val)
{
	int rc = regmap_write(dev_data->regmap, reg | 0x80, val);

	if (rc < 0)
		dev_err(&dev_data->client->dev, "error writing reg %u", reg);
	return rc;
}

static int cdce706_reg_update(struct cdce706_dev_data *dev_data, unsigned reg,
			      unsigned mask, unsigned val)
{
	int rc = regmap_update_bits(dev_data->regmap, reg | 0x80, mask, val);

	if (rc < 0)
		dev_err(&dev_data->client->dev, "error updating reg %u", reg);
	return rc;
}

static int cdce706_clkin_set_parent(struct clk_hw *hw, u8 index)
{
	struct cdce706_hw_data *hwd = to_hw_data(hw);

	hwd->parent = index;
	return 0;
}

static u8 cdce706_clkin_get_parent(struct clk_hw *hw)
{
	struct cdce706_hw_data *hwd = to_hw_data(hw);

	return hwd->parent;
}

static const struct clk_ops cdce706_clkin_ops = {
	.determine_rate = clk_hw_determine_rate_no_reparent,
	.set_parent = cdce706_clkin_set_parent,
	.get_parent = cdce706_clkin_get_parent,
};

static unsigned long cdce706_pll_recalc_rate(struct clk_hw *hw,
					     unsigned long parent_rate)
{
	struct cdce706_hw_data *hwd = to_hw_data(hw);

	dev_dbg(&hwd->dev_data->client->dev,
		"%s, pll: %d, mux: %d, mul: %u, div: %u\n",
		__func__, hwd->idx, hwd->mux, hwd->mul, hwd->div);

	if (!hwd->mux) {
		if (hwd->div && hwd->mul) {
			u64 res = (u64)parent_rate * hwd->mul;

			do_div(res, hwd->div);
			return res;
		}
	} else {
		if (hwd->div)
			return parent_rate / hwd->div;
	}
	return 0;
}

static long cdce706_pll_round_rate(struct clk_hw *hw, unsigned long rate,
				   unsigned long *parent_rate)
{
	struct cdce706_hw_data *hwd = to_hw_data(hw);
	unsigned long mul, div;
	u64 res;

	dev_dbg(&hwd->dev_data->client->dev,
		"%s, rate: %lu, parent_rate: %lu\n",
		__func__, rate, *parent_rate);

	rational_best_approximation(rate, *parent_rate,
				    CDCE706_PLL_N_MAX, CDCE706_PLL_M_MAX,
				    &mul, &div);
	hwd->mul = mul;
	hwd->div = div;

	dev_dbg(&hwd->dev_data->client->dev,
		"%s, pll: %d, mul: %lu, div: %lu\n",
		__func__, hwd->idx, mul, div);

	res = (u64)*parent_rate * hwd->mul;
	do_div(res, hwd->div);
	return res;
}

static int cdce706_pll_set_rate(struct clk_hw *hw, unsigned long rate,
				unsigned long parent_rate)
{
	struct cdce706_hw_data *hwd = to_hw_data(hw);
	unsigned long mul = hwd->mul, div = hwd->div;
	int err;

	dev_dbg(&hwd->dev_data->client->dev,
		"%s, pll: %d, mul: %lu, div: %lu\n",
		__func__, hwd->idx, mul, div);

	err = cdce706_reg_update(hwd->dev_data,
				 CDCE706_PLL_HI(hwd->idx),
				 CDCE706_PLL_HI_M_MASK | CDCE706_PLL_HI_N_MASK,
				 ((div >> 8) & CDCE706_PLL_HI_M_MASK) |
				 ((mul >> (8 - CDCE706_PLL_HI_N_SHIFT)) &
				  CDCE706_PLL_HI_N_MASK));
	if (err < 0)
		return err;

	err = cdce706_reg_write(hwd->dev_data,
				CDCE706_PLL_M_LOW(hwd->idx),
				div & CDCE706_PLL_LOW_M_MASK);
	if (err < 0)
		return err;

	err = cdce706_reg_write(hwd->dev_data,
				CDCE706_PLL_N_LOW(hwd->idx),
				mul & CDCE706_PLL_LOW_N_MASK);
	if (err < 0)
		return err;

	err = cdce706_reg_update(hwd->dev_data,
				 CDCE706_PLL_FVCO,
				 CDCE706_PLL_FVCO_MASK(hwd->idx),
				 rate > CDCE706_PLL_FREQ_HI ?
				 CDCE706_PLL_FVCO_MASK(hwd->idx) : 0);
	return err;
}

static const struct clk_ops cdce706_pll_ops = {
	.recalc_rate = cdce706_pll_recalc_rate,
	.round_rate = cdce706_pll_round_rate,
	.set_rate = cdce706_pll_set_rate,
};

static int cdce706_divider_set_parent(struct clk_hw *hw, u8 index)
{
	struct cdce706_hw_data *hwd = to_hw_data(hw);

	if (hwd->parent == index)
		return 0;
	hwd->parent = index;
	return cdce706_reg_update(hwd->dev_data,
				  CDCE706_DIVIDER_PLL(hwd->idx),
				  CDCE706_DIVIDER_PLL_MASK(hwd->idx),
				  index << CDCE706_DIVIDER_PLL_SHIFT(hwd->idx));
}

static u8 cdce706_divider_get_parent(struct clk_hw *hw)
{
	struct cdce706_hw_data *hwd = to_hw_data(hw);

	return hwd->parent;
}

static unsigned long cdce706_divider_recalc_rate(struct clk_hw *hw,
						 unsigned long parent_rate)
{
	struct cdce706_hw_data *hwd = to_hw_data(hw);

	dev_dbg(&hwd->dev_data->client->dev,
		"%s, divider: %d, div: %u\n",
		__func__, hwd->idx, hwd->div);
	if (hwd->div)
		return parent_rate / hwd->div;
	return 0;
}

static long cdce706_divider_round_rate(struct clk_hw *hw, unsigned long rate,
				       unsigned long *parent_rate)
{
	struct cdce706_hw_data *hwd = to_hw_data(hw);
	struct cdce706_dev_data *cdce = hwd->dev_data;
	unsigned long mul, div;

	dev_dbg(&hwd->dev_data->client->dev,
		"%s, rate: %lu, parent_rate: %lu\n",
		__func__, rate, *parent_rate);

	rational_best_approximation(rate, *parent_rate,
				    1, CDCE706_DIVIDER_DIVIDER_MAX,
				    &mul, &div);
	if (!mul)
		div = CDCE706_DIVIDER_DIVIDER_MAX;

	if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) {
		unsigned long best_diff = rate;
		unsigned long best_div = 0;
		struct clk *gp_clk = cdce->clkin_clk[cdce->clkin[0].parent];
		unsigned long gp_rate = gp_clk ? clk_get_rate(gp_clk) : 0;

		for (div = CDCE706_PLL_FREQ_MIN / rate; best_diff &&
		     div <= CDCE706_PLL_FREQ_MAX / rate; ++div) {
			unsigned long n, m;
			unsigned long diff;
			unsigned long div_rate;
			u64 div_rate64;

			if (rate * div < CDCE706_PLL_FREQ_MIN)
				continue;

			rational_best_approximation(rate * div, gp_rate,
						    CDCE706_PLL_N_MAX,
						    CDCE706_PLL_M_MAX,
						    &n, &m);
			div_rate64 = (u64)gp_rate * n;
			do_div(div_rate64, m);
			do_div(div_rate64, div);
			div_rate = div_rate64;
			diff = max(div_rate, rate) - min(div_rate, rate);

			if (diff < best_diff) {
				best_diff = diff;
				best_div = div;
				dev_dbg(&hwd->dev_data->client->dev,
					"%s, %lu * %lu / %lu / %lu = %lu\n",
					__func__, gp_rate, n, m, div, div_rate);
			}
		}

		div = best_div;

		dev_dbg(&hwd->dev_data->client->dev,
			"%s, altering parent rate: %lu -> %lu\n",
			__func__, *parent_rate, rate * div);
		*parent_rate = rate * div;
	}
	hwd->div = div;

	dev_dbg(&hwd->dev_data->client->dev,
		"%s, divider: %d, div: %lu\n",
		__func__, hwd->idx, div);

	return *parent_rate / div;
}

static int cdce706_divider_set_rate(struct clk_hw *hw, unsigned long rate,
				    unsigned long parent_rate)
{
	struct cdce706_hw_data *hwd = to_hw_data(hw);

	dev_dbg(&hwd->dev_data->client->dev,
		"%s, divider: %d, div: %u\n",
		__func__, hwd->idx, hwd->div);

	return cdce706_reg_update(hwd->dev_data,
				  CDCE706_DIVIDER(hwd->idx),
				  CDCE706_DIVIDER_DIVIDER_MASK,
				  hwd->div);
}

static const struct clk_ops cdce706_divider_ops = {
	.set_parent = cdce706_divider_set_parent,
	.get_parent = cdce706_divider_get_parent,
	.recalc_rate = cdce706_divider_recalc_rate,
	.round_rate = cdce706_divider_round_rate,
	.set_rate = cdce706_divider_set_rate,
};

static int cdce706_clkout_prepare(struct clk_hw *hw)
{
	struct cdce706_hw_data *hwd = to_hw_data(hw);

	return cdce706_reg_update(hwd->dev_data, CDCE706_CLKOUT(hwd->idx),
				  CDCE706_CLKOUT_ENABLE_MASK,
				  CDCE706_CLKOUT_ENABLE_MASK);
}

static void cdce706_clkout_unprepare(struct clk_hw *hw)
{
	struct cdce706_hw_data *hwd = to_hw_data(hw);

	cdce706_reg_update(hwd->dev_data, CDCE706_CLKOUT(hwd->idx),
			   CDCE706_CLKOUT_ENABLE_MASK, 0);
}

static int cdce706_clkout_set_parent(struct clk_hw *hw, u8 index)
{
	struct cdce706_hw_data *hwd = to_hw_data(hw);

	if (hwd->parent == index)
		return 0;
	hwd->parent = index;
	return cdce706_reg_update(hwd->dev_data,
				  CDCE706_CLKOUT(hwd->idx),
				  CDCE706_CLKOUT_ENABLE_MASK, index);
}

static u8 cdce706_clkout_get_parent(struct clk_hw *hw)
{
	struct cdce706_hw_data *hwd = to_hw_data(hw);

	return hwd->parent;
}

static unsigned long cdce706_clkout_recalc_rate(struct clk_hw *hw,
						unsigned long parent_rate)
{
	return parent_rate;
}

static long cdce706_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
				      unsigned long *parent_rate)
{
	*parent_rate = rate;
	return rate;
}

static int cdce706_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
				   unsigned long parent_rate)
{
	return 0;
}

static const struct clk_ops cdce706_clkout_ops = {
	.prepare = cdce706_clkout_prepare,
	.unprepare = cdce706_clkout_unprepare,
	.set_parent = cdce706_clkout_set_parent,
	.get_parent = cdce706_clkout_get_parent,
	.recalc_rate = cdce706_clkout_recalc_rate,
	.round_rate = cdce706_clkout_round_rate,
	.set_rate = cdce706_clkout_set_rate,
};

static int cdce706_register_hw(struct cdce706_dev_data *cdce,
			       struct cdce706_hw_data *hw, unsigned num_hw,
			       const char * const *clk_names,
			       struct clk_init_data *init)
{
	unsigned i;
	int ret;

	for (i = 0; i < num_hw; ++i, ++hw) {
		init->name = clk_names[i];
		hw->dev_data = cdce;
		hw->idx = i;
		hw->hw.init = init;
		ret = devm_clk_hw_register(&cdce->client->dev,
					    &hw->hw);
		if (ret) {
			dev_err(&cdce->client->dev, "Failed to register %s\n",
				clk_names[i]);
			return ret;
		}
	}
	return 0;
}

static int cdce706_register_clkin(struct cdce706_dev_data *cdce)
{
	struct clk_init_data init = {
		.ops = &cdce706_clkin_ops,
		.parent_names = cdce->clkin_name,
		.num_parents = ARRAY_SIZE(cdce->clkin_name),
	};
	unsigned i;
	int ret;
	unsigned clock, source;

	for (i = 0; i < ARRAY_SIZE(cdce->clkin_name); ++i) {
		struct clk *parent = devm_clk_get(&cdce->client->dev,
						  cdce706_source_name[i]);

		if (IS_ERR(parent)) {
			cdce->clkin_name[i] = cdce706_source_name[i];
		} else {
			cdce->clkin_name[i] = __clk_get_name(parent);
			cdce->clkin_clk[i] = parent;
		}
	}

	ret = cdce706_reg_read(cdce, CDCE706_CLKIN_SOURCE, &source);
	if (ret < 0)
		return ret;
	if ((source & CDCE706_CLKIN_SOURCE_MASK) ==
	    CDCE706_CLKIN_SOURCE_LVCMOS) {
		ret = cdce706_reg_read(cdce, CDCE706_CLKIN_CLOCK, &clock);
		if (ret < 0)
			return ret;
		cdce->clkin[0].parent = !!(clock & CDCE706_CLKIN_CLOCK_MASK);
	}

	ret = cdce706_register_hw(cdce, cdce->clkin,
				  ARRAY_SIZE(cdce->clkin),
				  cdce706_clkin_name, &init);
	return ret;
}

static int cdce706_register_plls(struct cdce706_dev_data *cdce)
{
	struct clk_init_data init = {
		.ops = &cdce706_pll_ops,
		.parent_names = cdce706_clkin_name,
		.num_parents = ARRAY_SIZE(cdce706_clkin_name),
	};
	unsigned i;
	int ret;
	unsigned mux;

	ret = cdce706_reg_read(cdce, CDCE706_PLL_MUX, &mux);
	if (ret < 0)
		return ret;

	for (i = 0; i < ARRAY_SIZE(cdce->pll); ++i) {
		unsigned m, n, v;

		ret = cdce706_reg_read(cdce, CDCE706_PLL_M_LOW(i), &m);
		if (ret < 0)
			return ret;
		ret = cdce706_reg_read(cdce, CDCE706_PLL_N_LOW(i), &n);
		if (ret < 0)
			return ret;
		ret = cdce706_reg_read(cdce, CDCE706_PLL_HI(i), &v);
		if (ret < 0)
			return ret;
		cdce->pll[i].div = m | ((v & CDCE706_PLL_HI_M_MASK) << 8);
		cdce->pll[i].mul = n | ((v & CDCE706_PLL_HI_N_MASK) <<
					(8 - CDCE706_PLL_HI_N_SHIFT));
		cdce->pll[i].mux = mux & CDCE706_PLL_MUX_MASK(i);
		dev_dbg(&cdce->client->dev,
			"%s: i: %u, div: %u, mul: %u, mux: %d\n", __func__, i,
			cdce->pll[i].div, cdce->pll[i].mul, cdce->pll[i].mux);
	}

	ret = cdce706_register_hw(cdce, cdce->pll,
				  ARRAY_SIZE(cdce->pll),
				  cdce706_pll_name, &init);
	return ret;
}

static int cdce706_register_dividers(struct cdce706_dev_data *cdce)
{
	struct clk_init_data init = {
		.ops = &cdce706_divider_ops,
		.parent_names = cdce706_divider_parent_name,
		.num_parents = ARRAY_SIZE(cdce706_divider_parent_name),
		.flags = CLK_SET_RATE_PARENT,
	};
	unsigned i;
	int ret;

	for (i = 0; i < ARRAY_SIZE(cdce->divider); ++i) {
		unsigned val;

		ret = cdce706_reg_read(cdce, CDCE706_DIVIDER_PLL(i), &val);
		if (ret < 0)
			return ret;
		cdce->divider[i].parent =
			(val & CDCE706_DIVIDER_PLL_MASK(i)) >>
			CDCE706_DIVIDER_PLL_SHIFT(i);

		ret = cdce706_reg_read(cdce, CDCE706_DIVIDER(i), &val);
		if (ret < 0)
			return ret;
		cdce->divider[i].div = val & CDCE706_DIVIDER_DIVIDER_MASK;
		dev_dbg(&cdce->client->dev,
			"%s: i: %u, parent: %u, div: %u\n", __func__, i,
			cdce->divider[i].parent, cdce->divider[i].div);
	}

	ret = cdce706_register_hw(cdce, cdce->divider,
				  ARRAY_SIZE(cdce->divider),
				  cdce706_divider_name, &init);
	return ret;
}

static int cdce706_register_clkouts(struct cdce706_dev_data *cdce)
{
	struct clk_init_data init = {
		.ops = &cdce706_clkout_ops,
		.parent_names = cdce706_divider_name,
		.num_parents = ARRAY_SIZE(cdce706_divider_name),
		.flags = CLK_SET_RATE_PARENT,
	};
	unsigned i;
	int ret;

	for (i = 0; i < ARRAY_SIZE(cdce->clkout); ++i) {
		unsigned val;

		ret = cdce706_reg_read(cdce, CDCE706_CLKOUT(i), &val);
		if (ret < 0)
			return ret;
		cdce->clkout[i].parent = val & CDCE706_CLKOUT_DIVIDER_MASK;
		dev_dbg(&cdce->client->dev,
			"%s: i: %u, parent: %u\n", __func__, i,
			cdce->clkout[i].parent);
	}

	return cdce706_register_hw(cdce, cdce->clkout,
				   ARRAY_SIZE(cdce->clkout),
				   cdce706_clkout_name, &init);
}

static struct clk_hw *
of_clk_cdce_get(struct of_phandle_args *clkspec, void *data)
{
	struct cdce706_dev_data *cdce = data;
	unsigned int idx = clkspec->args[0];

	if (idx >= ARRAY_SIZE(cdce->clkout)) {
		pr_err("%s: invalid index %u\n", __func__, idx);
		return ERR_PTR(-EINVAL);
	}

	return &cdce->clkout[idx].hw;
}

static int cdce706_probe(struct i2c_client *client)
{
	struct i2c_adapter *adapter = client->adapter;
	struct cdce706_dev_data *cdce;
	int ret;

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
		return -EIO;

	cdce = devm_kzalloc(&client->dev, sizeof(*cdce), GFP_KERNEL);
	if (!cdce)
		return -ENOMEM;

	cdce->client = client;
	cdce->regmap = devm_regmap_init_i2c(client, &cdce706_regmap_config);
	if (IS_ERR(cdce->regmap)) {
		dev_err(&client->dev, "Failed to initialize regmap\n");
		return -EINVAL;
	}

	i2c_set_clientdata(client, cdce);

	ret = cdce706_register_clkin(cdce);
	if (ret < 0)
		return ret;
	ret = cdce706_register_plls(cdce);
	if (ret < 0)
		return ret;
	ret = cdce706_register_dividers(cdce);
	if (ret < 0)
		return ret;
	ret = cdce706_register_clkouts(cdce);
	if (ret < 0)
		return ret;
	return devm_of_clk_add_hw_provider(&client->dev, of_clk_cdce_get,
					   cdce);
}

#ifdef CONFIG_OF
static const struct of_device_id cdce706_dt_match[] = {
	{ .compatible = "ti,cdce706" },
	{ },
};
MODULE_DEVICE_TABLE(of, cdce706_dt_match);
#endif

static const struct i2c_device_id cdce706_id[] = {
	{ "cdce706", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, cdce706_id);

static struct i2c_driver cdce706_i2c_driver = {
	.driver	= {
		.name	= "cdce706",
		.of_match_table = of_match_ptr(cdce706_dt_match),
	},
	.probe_new	= cdce706_probe,
	.id_table	= cdce706_id,
};
module_i2c_driver(cdce706_i2c_driver);

MODULE_AUTHOR("Max Filippov <jcmvbkbc@gmail.com>");
MODULE_DESCRIPTION("TI CDCE 706 clock synthesizer driver");
MODULE_LICENSE("GPL");