/*
 * Helper routines for R-Car sound ADG.
 *
 *  Copyright (C) 2013  Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/clk-provider.h>
#include "rsnd.h"

#define CLKA	0
#define CLKB	1
#define CLKC	2
#define CLKI	3
#define CLKMAX	4

#define CLKOUT	0
#define CLKOUT1	1
#define CLKOUT2	2
#define CLKOUT3	3
#define CLKOUTMAX 4

#define BRRx_MASK(x) (0x3FF & x)

static struct rsnd_mod_ops adg_ops = {
	.name = "adg",
};

struct rsnd_adg {
	struct clk *clk[CLKMAX];
	struct clk *clkout[CLKOUTMAX];
	struct clk_onecell_data onecell;
	struct rsnd_mod mod;

	int rbga_rate_for_441khz; /* RBGA */
	int rbgb_rate_for_48khz;  /* RBGB */
};

#define for_each_rsnd_clk(pos, adg, i)		\
	for (i = 0;				\
	     (i < CLKMAX) &&			\
	     ((pos) = adg->clk[i]);		\
	     i++)
#define for_each_rsnd_clkout(pos, adg, i)	\
	for (i = 0;				\
	     (i < CLKOUTMAX) &&			\
	     ((pos) = adg->clkout[i]);	\
	     i++)
#define rsnd_priv_to_adg(priv) ((struct rsnd_adg *)(priv)->adg)

static u32 rsnd_adg_calculate_rbgx(unsigned long div)
{
	int i, ratio;

	if (!div)
		return 0;

	for (i = 3; i >= 0; i--) {
		ratio = 2 << (i * 2);
		if (0 == (div % ratio))
			return (u32)((i << 8) | ((div / ratio) - 1));
	}

	return ~0;
}

static u32 rsnd_adg_ssi_ws_timing_gen2(struct rsnd_dai_stream *io)
{
	struct rsnd_mod *ssi_mod = rsnd_io_to_mod_ssi(io);
	int id = rsnd_mod_id(ssi_mod);
	int ws = id;

	if (rsnd_ssi_is_pin_sharing(io)) {
		switch (id) {
		case 1:
		case 2:
			ws = 0;
			break;
		case 4:
			ws = 3;
			break;
		case 8:
			ws = 7;
			break;
		}
	}

	return (0x6 + ws) << 8;
}

static void __rsnd_adg_get_timesel_ratio(struct rsnd_priv *priv,
				       struct rsnd_dai_stream *io,
				       unsigned int target_rate,
				       unsigned int *target_val,
				       unsigned int *target_en)
{
	struct rsnd_adg *adg = rsnd_priv_to_adg(priv);
	struct device *dev = rsnd_priv_to_dev(priv);
	int idx, sel, div, step;
	unsigned int val, en;
	unsigned int min, diff;
	unsigned int sel_rate[] = {
		clk_get_rate(adg->clk[CLKA]),	/* 0000: CLKA */
		clk_get_rate(adg->clk[CLKB]),	/* 0001: CLKB */
		clk_get_rate(adg->clk[CLKC]),	/* 0010: CLKC */
		adg->rbga_rate_for_441khz,	/* 0011: RBGA */
		adg->rbgb_rate_for_48khz,	/* 0100: RBGB */
	};

	min = ~0;
	val = 0;
	en = 0;
	for (sel = 0; sel < ARRAY_SIZE(sel_rate); sel++) {
		idx = 0;
		step = 2;

		if (!sel_rate[sel])
			continue;

		for (div = 2; div <= 98304; div += step) {
			diff = abs(target_rate - sel_rate[sel] / div);
			if (min > diff) {
				val = (sel << 8) | idx;
				min = diff;
				en = 1 << (sel + 1); /* fixme */
			}

			/*
			 * step of 0_0000 / 0_0001 / 0_1101
			 * are out of order
			 */
			if ((idx > 2) && (idx % 2))
				step *= 2;
			if (idx == 0x1c) {
				div += step;
				step *= 2;
			}
			idx++;
		}
	}

	if (min == ~0) {
		dev_err(dev, "no Input clock\n");
		return;
	}

	*target_val = val;
	if (target_en)
		*target_en = en;
}

static void rsnd_adg_get_timesel_ratio(struct rsnd_priv *priv,
				       struct rsnd_dai_stream *io,
				       unsigned int in_rate,
				       unsigned int out_rate,
				       u32 *in, u32 *out, u32 *en)
{
	struct snd_pcm_runtime *runtime = rsnd_io_to_runtime(io);
	unsigned int target_rate;
	u32 *target_val;
	u32 _in;
	u32 _out;
	u32 _en;

	/* default = SSI WS */
	_in =
	_out = rsnd_adg_ssi_ws_timing_gen2(io);

	target_rate = 0;
	target_val = NULL;
	_en = 0;
	if (runtime->rate != in_rate) {
		target_rate = out_rate;
		target_val  = &_out;
	} else if (runtime->rate != out_rate) {
		target_rate = in_rate;
		target_val  = &_in;
	}

	if (target_rate)
		__rsnd_adg_get_timesel_ratio(priv, io,
					     target_rate,
					     target_val, &_en);

	if (in)
		*in = _in;
	if (out)
		*out = _out;
	if (en)
		*en = _en;
}

int rsnd_adg_set_cmd_timsel_gen2(struct rsnd_mod *cmd_mod,
				 struct rsnd_dai_stream *io)
{
	struct rsnd_priv *priv = rsnd_mod_to_priv(cmd_mod);
	struct rsnd_adg *adg = rsnd_priv_to_adg(priv);
	struct rsnd_mod *adg_mod = rsnd_mod_get(adg);
	int id = rsnd_mod_id(cmd_mod);
	int shift = (id % 2) ? 16 : 0;
	u32 mask, val;

	rsnd_adg_get_timesel_ratio(priv, io,
				   rsnd_src_get_in_rate(priv, io),
				   rsnd_src_get_out_rate(priv, io),
				   NULL, &val, NULL);

	val  = val	<< shift;
	mask = 0xffff	<< shift;

	rsnd_mod_bset(adg_mod, CMDOUT_TIMSEL, mask, val);

	return 0;
}

int rsnd_adg_set_src_timesel_gen2(struct rsnd_mod *src_mod,
				  struct rsnd_dai_stream *io,
				  unsigned int in_rate,
				  unsigned int out_rate)
{
	struct rsnd_priv *priv = rsnd_mod_to_priv(src_mod);
	struct rsnd_adg *adg = rsnd_priv_to_adg(priv);
	struct rsnd_mod *adg_mod = rsnd_mod_get(adg);
	u32 in, out;
	u32 mask, en;
	int id = rsnd_mod_id(src_mod);
	int shift = (id % 2) ? 16 : 0;

	rsnd_mod_confirm_src(src_mod);

	rsnd_adg_get_timesel_ratio(priv, io,
				   in_rate, out_rate,
				   &in, &out, &en);

	in   = in	<< shift;
	out  = out	<< shift;
	mask = 0xffff	<< shift;

	switch (id / 2) {
	case 0:
		rsnd_mod_bset(adg_mod, SRCIN_TIMSEL0,  mask, in);
		rsnd_mod_bset(adg_mod, SRCOUT_TIMSEL0, mask, out);
		break;
	case 1:
		rsnd_mod_bset(adg_mod, SRCIN_TIMSEL1,  mask, in);
		rsnd_mod_bset(adg_mod, SRCOUT_TIMSEL1, mask, out);
		break;
	case 2:
		rsnd_mod_bset(adg_mod, SRCIN_TIMSEL2,  mask, in);
		rsnd_mod_bset(adg_mod, SRCOUT_TIMSEL2, mask, out);
		break;
	case 3:
		rsnd_mod_bset(adg_mod, SRCIN_TIMSEL3,  mask, in);
		rsnd_mod_bset(adg_mod, SRCOUT_TIMSEL3, mask, out);
		break;
	case 4:
		rsnd_mod_bset(adg_mod, SRCIN_TIMSEL4,  mask, in);
		rsnd_mod_bset(adg_mod, SRCOUT_TIMSEL4, mask, out);
		break;
	}

	if (en)
		rsnd_mod_bset(adg_mod, DIV_EN, en, en);

	return 0;
}

static void rsnd_adg_set_ssi_clk(struct rsnd_mod *ssi_mod, u32 val)
{
	struct rsnd_priv *priv = rsnd_mod_to_priv(ssi_mod);
	struct rsnd_adg *adg = rsnd_priv_to_adg(priv);
	struct rsnd_mod *adg_mod = rsnd_mod_get(adg);
	int id = rsnd_mod_id(ssi_mod);
	int shift = (id % 4) * 8;
	u32 mask = 0xFF << shift;

	rsnd_mod_confirm_ssi(ssi_mod);

	val = val << shift;

	/*
	 * SSI 8 is not connected to ADG.
	 * it works with SSI 7
	 */
	if (id == 8)
		return;

	switch (id / 4) {
	case 0:
		rsnd_mod_bset(adg_mod, AUDIO_CLK_SEL0, mask, val);
		break;
	case 1:
		rsnd_mod_bset(adg_mod, AUDIO_CLK_SEL1, mask, val);
		break;
	case 2:
		rsnd_mod_bset(adg_mod, AUDIO_CLK_SEL2, mask, val);
		break;
	}
}

int rsnd_adg_ssi_clk_stop(struct rsnd_mod *ssi_mod)
{
	rsnd_adg_set_ssi_clk(ssi_mod, 0);

	return 0;
}

int rsnd_adg_ssi_clk_try_start(struct rsnd_mod *ssi_mod, unsigned int rate)
{
	struct rsnd_priv *priv = rsnd_mod_to_priv(ssi_mod);
	struct rsnd_adg *adg = rsnd_priv_to_adg(priv);
	struct device *dev = rsnd_priv_to_dev(priv);
	struct clk *clk;
	int i;
	u32 data;
	int sel_table[] = {
		[CLKA] = 0x1,
		[CLKB] = 0x2,
		[CLKC] = 0x3,
		[CLKI] = 0x0,
	};

	dev_dbg(dev, "request clock = %d\n", rate);

	/*
	 * find suitable clock from
	 * AUDIO_CLKA/AUDIO_CLKB/AUDIO_CLKC/AUDIO_CLKI.
	 */
	data = 0;
	for_each_rsnd_clk(clk, adg, i) {
		if (rate == clk_get_rate(clk)) {
			data = sel_table[i];
			goto found_clock;
		}
	}

	/*
	 * find divided clock from BRGA/BRGB
	 */
	if (rate  == adg->rbga_rate_for_441khz) {
		data = 0x10;
		goto found_clock;
	}

	if (rate == adg->rbgb_rate_for_48khz) {
		data = 0x20;
		goto found_clock;
	}

	return -EIO;

found_clock:

	rsnd_adg_set_ssi_clk(ssi_mod, data);

	dev_dbg(dev, "ADG: %s[%d] selects 0x%x for %d\n",
		rsnd_mod_name(ssi_mod), rsnd_mod_id(ssi_mod),
		data, rate);

	return 0;
}

static void rsnd_adg_get_clkin(struct rsnd_priv *priv,
			       struct rsnd_adg *adg)
{
	struct device *dev = rsnd_priv_to_dev(priv);
	struct clk *clk;
	static const char * const clk_name[] = {
		[CLKA]	= "clk_a",
		[CLKB]	= "clk_b",
		[CLKC]	= "clk_c",
		[CLKI]	= "clk_i",
	};
	int i, ret;

	for (i = 0; i < CLKMAX; i++) {
		clk = devm_clk_get(dev, clk_name[i]);
		adg->clk[i] = IS_ERR(clk) ? NULL : clk;
	}

	for_each_rsnd_clk(clk, adg, i) {
		ret = clk_prepare_enable(clk);
		if (ret < 0)
			dev_warn(dev, "can't use clk %d\n", i);

		dev_dbg(dev, "clk %d : %p : %ld\n", i, clk, clk_get_rate(clk));
	}
}

static void rsnd_adg_get_clkout(struct rsnd_priv *priv,
				struct rsnd_adg *adg)
{
	struct clk *clk;
	struct rsnd_mod *adg_mod = rsnd_mod_get(adg);
	struct device *dev = rsnd_priv_to_dev(priv);
	struct device_node *np = dev->of_node;
	u32 ckr, rbgx, rbga, rbgb;
	u32 rate, req_rate = 0, div;
	uint32_t count = 0;
	unsigned long req_48kHz_rate, req_441kHz_rate;
	int i;
	const char *parent_clk_name = NULL;
	static const char * const clkout_name[] = {
		[CLKOUT]  = "audio_clkout",
		[CLKOUT1] = "audio_clkout1",
		[CLKOUT2] = "audio_clkout2",
		[CLKOUT3] = "audio_clkout3",
	};
	int brg_table[] = {
		[CLKA] = 0x0,
		[CLKB] = 0x1,
		[CLKC] = 0x4,
		[CLKI] = 0x2,
	};

	of_property_read_u32(np, "#clock-cells", &count);

	/*
	 * ADG supports BRRA/BRRB output only
	 * this means all clkout0/1/2/3 will be same rate
	 */
	of_property_read_u32(np, "clock-frequency", &req_rate);
	req_48kHz_rate = 0;
	req_441kHz_rate = 0;
	if (0 == (req_rate % 44100))
		req_441kHz_rate = req_rate;
	if (0 == (req_rate % 48000))
		req_48kHz_rate = req_rate;

	/*
	 * This driver is assuming that AUDIO_CLKA/AUDIO_CLKB/AUDIO_CLKC
	 * have 44.1kHz or 48kHz base clocks for now.
	 *
	 * SSI itself can divide parent clock by 1/1 - 1/16
	 * see
	 *	rsnd_adg_ssi_clk_try_start()
	 *	rsnd_ssi_master_clk_start()
	 */
	ckr = 0;
	rbga = 2; /* default 1/6 */
	rbgb = 2; /* default 1/6 */
	adg->rbga_rate_for_441khz	= 0;
	adg->rbgb_rate_for_48khz	= 0;
	for_each_rsnd_clk(clk, adg, i) {
		rate = clk_get_rate(clk);

		if (0 == rate) /* not used */
			continue;

		/* RBGA */
		if (!adg->rbga_rate_for_441khz && (0 == rate % 44100)) {
			div = 6;
			if (req_441kHz_rate)
				div = rate / req_441kHz_rate;
			rbgx = rsnd_adg_calculate_rbgx(div);
			if (BRRx_MASK(rbgx) == rbgx) {
				rbga = rbgx;
				adg->rbga_rate_for_441khz = rate / div;
				ckr |= brg_table[i] << 20;
				if (req_441kHz_rate)
					parent_clk_name = __clk_get_name(clk);
			}
		}

		/* RBGB */
		if (!adg->rbgb_rate_for_48khz && (0 == rate % 48000)) {
			div = 6;
			if (req_48kHz_rate)
				div = rate / req_48kHz_rate;
			rbgx = rsnd_adg_calculate_rbgx(div);
			if (BRRx_MASK(rbgx) == rbgx) {
				rbgb = rbgx;
				adg->rbgb_rate_for_48khz = rate / div;
				ckr |= brg_table[i] << 16;
				if (req_48kHz_rate) {
					parent_clk_name = __clk_get_name(clk);
					ckr |= 0x80000000;
				}
			}
		}
	}

	/*
	 * ADG supports BRRA/BRRB output only.
	 * this means all clkout0/1/2/3 will be * same rate
	 */

	/*
	 * for clkout
	 */
	if (!count) {
		clk = clk_register_fixed_rate(dev, clkout_name[CLKOUT],
					      parent_clk_name, 0, req_rate);
		if (!IS_ERR(clk)) {
			adg->clkout[CLKOUT] = clk;
			of_clk_add_provider(np, of_clk_src_simple_get, clk);
		}
	}
	/*
	 * for clkout0/1/2/3
	 */
	else {
		for (i = 0; i < CLKOUTMAX; i++) {
			clk = clk_register_fixed_rate(dev, clkout_name[i],
						      parent_clk_name, 0,
						      req_rate);
			if (!IS_ERR(clk)) {
				adg->onecell.clks	= adg->clkout;
				adg->onecell.clk_num	= CLKOUTMAX;

				adg->clkout[i] = clk;

				of_clk_add_provider(np, of_clk_src_onecell_get,
						    &adg->onecell);
			}
		}
	}

	rsnd_mod_bset(adg_mod, SSICKR, 0x80FF0000, ckr);
	rsnd_mod_write(adg_mod, BRRA,  rbga);
	rsnd_mod_write(adg_mod, BRRB,  rbgb);

	for_each_rsnd_clkout(clk, adg, i)
		dev_dbg(dev, "clkout %d : %p : %ld\n", i, clk, clk_get_rate(clk));
	dev_dbg(dev, "SSICKR = 0x%08x, BRRA/BRRB = 0x%x/0x%x\n",
		ckr, rbga, rbgb);
}

int rsnd_adg_probe(struct rsnd_priv *priv)
{
	struct rsnd_adg *adg;
	struct device *dev = rsnd_priv_to_dev(priv);

	adg = devm_kzalloc(dev, sizeof(*adg), GFP_KERNEL);
	if (!adg) {
		dev_err(dev, "ADG allocate failed\n");
		return -ENOMEM;
	}

	rsnd_mod_init(priv, &adg->mod, &adg_ops,
		      NULL, NULL, 0, 0);

	rsnd_adg_get_clkin(priv, adg);
	rsnd_adg_get_clkout(priv, adg);

	priv->adg = adg;

	return 0;
}

void rsnd_adg_remove(struct rsnd_priv *priv)
{
	struct rsnd_adg *adg = rsnd_priv_to_adg(priv);
	struct clk *clk;
	int i;

	for_each_rsnd_clk(clk, adg, i) {
		clk_disable_unprepare(clk);
	}
}