/*
 *  Copyright (C) 2016 Atmel Corporation,
 *		       Songjun Wu <songjun.wu@atmel.com>,
 *                     Nicolas Ferre <nicolas.ferre@atmel.com>
 *  Copyright (C) 2017 Free Electrons,
 *		       Quentin Schulz <quentin.schulz@free-electrons.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.
 *
 * The Sama5d2 SoC has two audio PLLs (PMC and PAD) that shares the same parent
 * (FRAC). FRAC can output between 620 and 700MHz and only multiply the rate of
 * its own parent. PMC and PAD can then divide the FRAC rate to best match the
 * asked rate.
 *
 * Traits of FRAC clock:
 * enable - clk_enable writes nd, fracr parameters and enables PLL
 * rate - rate is adjustable.
 *        clk->rate = parent->rate * ((nd + 1) + (fracr / 2^22))
 * parent - fixed parent.  No clk_set_parent support
 *
 * Traits of PMC clock:
 * enable - clk_enable writes qdpmc, and enables PMC output
 * rate - rate is adjustable.
 *        clk->rate = parent->rate / (qdpmc + 1)
 * parent - fixed parent.  No clk_set_parent support
 *
 * Traits of PAD clock:
 * enable - clk_enable writes divisors and enables PAD output
 * rate - rate is adjustable.
 *        clk->rate = parent->rate / (qdaudio * div))
 * parent - fixed parent.  No clk_set_parent support
 *
 */

#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/clk/at91_pmc.h>
#include <linux/of.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
#include <linux/slab.h>

#include "pmc.h"

#define AUDIO_PLL_DIV_FRAC	BIT(22)
#define AUDIO_PLL_ND_MAX	(AT91_PMC_AUDIO_PLL_ND_MASK >> \
					AT91_PMC_AUDIO_PLL_ND_OFFSET)

#define AUDIO_PLL_QDPAD(qd, div)	((AT91_PMC_AUDIO_PLL_QDPAD_EXTDIV(qd) & \
					  AT91_PMC_AUDIO_PLL_QDPAD_EXTDIV_MASK) | \
					 (AT91_PMC_AUDIO_PLL_QDPAD_DIV(div) & \
					  AT91_PMC_AUDIO_PLL_QDPAD_DIV_MASK))

#define AUDIO_PLL_QDPMC_MAX		(AT91_PMC_AUDIO_PLL_QDPMC_MASK >> \
						AT91_PMC_AUDIO_PLL_QDPMC_OFFSET)

#define AUDIO_PLL_FOUT_MIN	620000000UL
#define AUDIO_PLL_FOUT_MAX	700000000UL

struct clk_audio_frac {
	struct clk_hw hw;
	struct regmap *regmap;
	u32 fracr;
	u8 nd;
};

struct clk_audio_pad {
	struct clk_hw hw;
	struct regmap *regmap;
	u8 qdaudio;
	u8 div;
};

struct clk_audio_pmc {
	struct clk_hw hw;
	struct regmap *regmap;
	u8 qdpmc;
};

#define to_clk_audio_frac(hw) container_of(hw, struct clk_audio_frac, hw)
#define to_clk_audio_pad(hw) container_of(hw, struct clk_audio_pad, hw)
#define to_clk_audio_pmc(hw) container_of(hw, struct clk_audio_pmc, hw)

static int clk_audio_pll_frac_enable(struct clk_hw *hw)
{
	struct clk_audio_frac *frac = to_clk_audio_frac(hw);

	regmap_update_bits(frac->regmap, AT91_PMC_AUDIO_PLL0,
			   AT91_PMC_AUDIO_PLL_RESETN, 0);
	regmap_update_bits(frac->regmap, AT91_PMC_AUDIO_PLL0,
			   AT91_PMC_AUDIO_PLL_RESETN,
			   AT91_PMC_AUDIO_PLL_RESETN);
	regmap_update_bits(frac->regmap, AT91_PMC_AUDIO_PLL1,
			   AT91_PMC_AUDIO_PLL_FRACR_MASK, frac->fracr);

	/*
	 * reset and enable have to be done in 2 separated writes
	 * for AT91_PMC_AUDIO_PLL0
	 */
	regmap_update_bits(frac->regmap, AT91_PMC_AUDIO_PLL0,
			   AT91_PMC_AUDIO_PLL_PLLEN |
			   AT91_PMC_AUDIO_PLL_ND_MASK,
			   AT91_PMC_AUDIO_PLL_PLLEN |
			   AT91_PMC_AUDIO_PLL_ND(frac->nd));

	return 0;
}

static int clk_audio_pll_pad_enable(struct clk_hw *hw)
{
	struct clk_audio_pad *apad_ck = to_clk_audio_pad(hw);

	regmap_update_bits(apad_ck->regmap, AT91_PMC_AUDIO_PLL1,
			   AT91_PMC_AUDIO_PLL_QDPAD_MASK,
			   AUDIO_PLL_QDPAD(apad_ck->qdaudio, apad_ck->div));
	regmap_update_bits(apad_ck->regmap, AT91_PMC_AUDIO_PLL0,
			   AT91_PMC_AUDIO_PLL_PADEN, AT91_PMC_AUDIO_PLL_PADEN);

	return 0;
}

static int clk_audio_pll_pmc_enable(struct clk_hw *hw)
{
	struct clk_audio_pmc *apmc_ck = to_clk_audio_pmc(hw);

	regmap_update_bits(apmc_ck->regmap, AT91_PMC_AUDIO_PLL0,
			   AT91_PMC_AUDIO_PLL_PMCEN |
			   AT91_PMC_AUDIO_PLL_QDPMC_MASK,
			   AT91_PMC_AUDIO_PLL_PMCEN |
			   AT91_PMC_AUDIO_PLL_QDPMC(apmc_ck->qdpmc));
	return 0;
}

static void clk_audio_pll_frac_disable(struct clk_hw *hw)
{
	struct clk_audio_frac *frac = to_clk_audio_frac(hw);

	regmap_update_bits(frac->regmap, AT91_PMC_AUDIO_PLL0,
			   AT91_PMC_AUDIO_PLL_PLLEN, 0);
	/* do it in 2 separated writes */
	regmap_update_bits(frac->regmap, AT91_PMC_AUDIO_PLL0,
			   AT91_PMC_AUDIO_PLL_RESETN, 0);
}

static void clk_audio_pll_pad_disable(struct clk_hw *hw)
{
	struct clk_audio_pad *apad_ck = to_clk_audio_pad(hw);

	regmap_update_bits(apad_ck->regmap, AT91_PMC_AUDIO_PLL0,
			   AT91_PMC_AUDIO_PLL_PADEN, 0);
}

static void clk_audio_pll_pmc_disable(struct clk_hw *hw)
{
	struct clk_audio_pmc *apmc_ck = to_clk_audio_pmc(hw);

	regmap_update_bits(apmc_ck->regmap, AT91_PMC_AUDIO_PLL0,
			   AT91_PMC_AUDIO_PLL_PMCEN, 0);
}

static unsigned long clk_audio_pll_fout(unsigned long parent_rate,
					unsigned long nd, unsigned long fracr)
{
	unsigned long long fr = (unsigned long long)parent_rate * fracr;

	pr_debug("A PLL: %s, fr = %llu\n", __func__, fr);

	fr = DIV_ROUND_CLOSEST_ULL(fr, AUDIO_PLL_DIV_FRAC);

	pr_debug("A PLL: %s, fr = %llu\n", __func__, fr);

	return parent_rate * (nd + 1) + fr;
}

static unsigned long clk_audio_pll_frac_recalc_rate(struct clk_hw *hw,
						    unsigned long parent_rate)
{
	struct clk_audio_frac *frac = to_clk_audio_frac(hw);
	unsigned long fout;

	fout = clk_audio_pll_fout(parent_rate, frac->nd, frac->fracr);

	pr_debug("A PLL: %s, fout = %lu (nd = %u, fracr = %lu)\n", __func__,
		 fout, frac->nd, (unsigned long)frac->fracr);

	return fout;
}

static unsigned long clk_audio_pll_pad_recalc_rate(struct clk_hw *hw,
						   unsigned long parent_rate)
{
	struct clk_audio_pad *apad_ck = to_clk_audio_pad(hw);
	unsigned long apad_rate = 0;

	if (apad_ck->qdaudio && apad_ck->div)
		apad_rate = parent_rate / (apad_ck->qdaudio * apad_ck->div);

	pr_debug("A PLL/PAD: %s, apad_rate = %lu (div = %u, qdaudio = %u)\n",
		 __func__, apad_rate, apad_ck->div, apad_ck->qdaudio);

	return apad_rate;
}

static unsigned long clk_audio_pll_pmc_recalc_rate(struct clk_hw *hw,
						   unsigned long parent_rate)
{
	struct clk_audio_pmc *apmc_ck = to_clk_audio_pmc(hw);
	unsigned long apmc_rate = 0;

	apmc_rate = parent_rate / (apmc_ck->qdpmc + 1);

	pr_debug("A PLL/PMC: %s, apmc_rate = %lu (qdpmc = %u)\n", __func__,
		 apmc_rate, apmc_ck->qdpmc);

	return apmc_rate;
}

static int clk_audio_pll_frac_compute_frac(unsigned long rate,
					   unsigned long parent_rate,
					   unsigned long *nd,
					   unsigned long *fracr)
{
	unsigned long long tmp, rem;

	if (!rate)
		return -EINVAL;

	tmp = rate;
	rem = do_div(tmp, parent_rate);
	if (!tmp || tmp >= AUDIO_PLL_ND_MAX)
		return -EINVAL;

	*nd = tmp - 1;

	tmp = rem * AUDIO_PLL_DIV_FRAC;
	tmp = DIV_ROUND_CLOSEST_ULL(tmp, parent_rate);
	if (tmp > AT91_PMC_AUDIO_PLL_FRACR_MASK)
		return -EINVAL;

	/* we can cast here as we verified the bounds just above */
	*fracr = (unsigned long)tmp;

	return 0;
}

static int clk_audio_pll_frac_determine_rate(struct clk_hw *hw,
					     struct clk_rate_request *req)
{
	unsigned long fracr, nd;
	int ret;

	pr_debug("A PLL: %s, rate = %lu (parent_rate = %lu)\n", __func__,
		 req->rate, req->best_parent_rate);

	req->rate = clamp(req->rate, AUDIO_PLL_FOUT_MIN, AUDIO_PLL_FOUT_MAX);

	req->min_rate = max(req->min_rate, AUDIO_PLL_FOUT_MIN);
	req->max_rate = min(req->max_rate, AUDIO_PLL_FOUT_MAX);

	ret = clk_audio_pll_frac_compute_frac(req->rate, req->best_parent_rate,
					      &nd, &fracr);
	if (ret)
		return ret;

	req->rate = clk_audio_pll_fout(req->best_parent_rate, nd, fracr);

	req->best_parent_hw = clk_hw_get_parent(hw);

	pr_debug("A PLL: %s, best_rate = %lu (nd = %lu, fracr = %lu)\n",
		 __func__, req->rate, nd, fracr);

	return 0;
}

static long clk_audio_pll_pad_round_rate(struct clk_hw *hw, unsigned long rate,
					 unsigned long *parent_rate)
{
	struct clk_hw *pclk = clk_hw_get_parent(hw);
	long best_rate = -EINVAL;
	unsigned long best_parent_rate;
	unsigned long tmp_qd;
	u32 div;
	long tmp_rate;
	int tmp_diff;
	int best_diff = -1;

	pr_debug("A PLL/PAD: %s, rate = %lu (parent_rate = %lu)\n", __func__,
		 rate, *parent_rate);

	/*
	 * Rate divisor is actually made of two different divisors, multiplied
	 * between themselves before dividing the rate.
	 * tmp_qd goes from 1 to 31 and div is either 2 or 3.
	 * In order to avoid testing twice the rate divisor (e.g. divisor 12 can
	 * be found with (tmp_qd, div) = (2, 6) or (3, 4)), we remove any loop
	 * for a rate divisor when div is 2 and tmp_qd is a multiple of 3.
	 * We cannot inverse it (condition div is 3 and tmp_qd is even) or we
	 * would miss some rate divisor that aren't reachable with div being 2
	 * (e.g. rate divisor 90 is made with div = 3 and tmp_qd = 30, thus
	 * tmp_qd is even so we skip it because we think div 2 could make this
	 * rate divisor which isn't possible since tmp_qd has to be <= 31).
	 */
	for (tmp_qd = 1; tmp_qd < AT91_PMC_AUDIO_PLL_QDPAD_EXTDIV_MAX; tmp_qd++)
		for (div = 2; div <= 3; div++) {
			if (div == 2 && tmp_qd % 3 == 0)
				continue;

			best_parent_rate = clk_hw_round_rate(pclk,
							rate * tmp_qd * div);
			tmp_rate = best_parent_rate / (div * tmp_qd);
			tmp_diff = abs(rate - tmp_rate);

			if (best_diff < 0 || best_diff > tmp_diff) {
				*parent_rate = best_parent_rate;
				best_rate = tmp_rate;
				best_diff = tmp_diff;
			}
		}

	pr_debug("A PLL/PAD: %s, best_rate = %ld, best_parent_rate = %lu\n",
		 __func__, best_rate, best_parent_rate);

	return best_rate;
}

static long clk_audio_pll_pmc_round_rate(struct clk_hw *hw, unsigned long rate,
					 unsigned long *parent_rate)
{
	struct clk_hw *pclk = clk_hw_get_parent(hw);
	long best_rate = -EINVAL;
	unsigned long best_parent_rate = 0;
	u32 tmp_qd = 0, div;
	long tmp_rate;
	int tmp_diff;
	int best_diff = -1;

	pr_debug("A PLL/PMC: %s, rate = %lu (parent_rate = %lu)\n", __func__,
		 rate, *parent_rate);

	if (!rate)
		return 0;

	best_parent_rate = clk_round_rate(pclk->clk, 1);
	div = max(best_parent_rate / rate, 1UL);
	for (; div <= AUDIO_PLL_QDPMC_MAX; div++) {
		best_parent_rate = clk_round_rate(pclk->clk, rate * div);
		tmp_rate = best_parent_rate / div;
		tmp_diff = abs(rate - tmp_rate);

		if (best_diff < 0 || best_diff > tmp_diff) {
			*parent_rate = best_parent_rate;
			best_rate = tmp_rate;
			best_diff = tmp_diff;
			tmp_qd = div;
			if (!best_diff)
				break;	/* got exact match */
		}
	}

	pr_debug("A PLL/PMC: %s, best_rate = %ld, best_parent_rate = %lu (qd = %d)\n",
		 __func__, best_rate, *parent_rate, tmp_qd - 1);

	return best_rate;
}

static int clk_audio_pll_frac_set_rate(struct clk_hw *hw, unsigned long rate,
				       unsigned long parent_rate)
{
	struct clk_audio_frac *frac = to_clk_audio_frac(hw);
	unsigned long fracr, nd;
	int ret;

	pr_debug("A PLL: %s, rate = %lu (parent_rate = %lu)\n", __func__, rate,
		 parent_rate);

	if (rate < AUDIO_PLL_FOUT_MIN || rate > AUDIO_PLL_FOUT_MAX)
		return -EINVAL;

	ret = clk_audio_pll_frac_compute_frac(rate, parent_rate, &nd, &fracr);
	if (ret)
		return ret;

	frac->nd = nd;
	frac->fracr = fracr;

	return 0;
}

static int clk_audio_pll_pad_set_rate(struct clk_hw *hw, unsigned long rate,
				      unsigned long parent_rate)
{
	struct clk_audio_pad *apad_ck = to_clk_audio_pad(hw);
	u8 tmp_div;

	pr_debug("A PLL/PAD: %s, rate = %lu (parent_rate = %lu)\n", __func__,
		 rate, parent_rate);

	if (!rate)
		return -EINVAL;

	tmp_div = parent_rate / rate;
	if (tmp_div % 3 == 0) {
		apad_ck->qdaudio = tmp_div / 3;
		apad_ck->div = 3;
	} else {
		apad_ck->qdaudio = tmp_div / 2;
		apad_ck->div = 2;
	}

	return 0;
}

static int clk_audio_pll_pmc_set_rate(struct clk_hw *hw, unsigned long rate,
				      unsigned long parent_rate)
{
	struct clk_audio_pmc *apmc_ck = to_clk_audio_pmc(hw);

	if (!rate)
		return -EINVAL;

	pr_debug("A PLL/PMC: %s, rate = %lu (parent_rate = %lu)\n", __func__,
		 rate, parent_rate);

	apmc_ck->qdpmc = parent_rate / rate - 1;

	return 0;
}

static const struct clk_ops audio_pll_frac_ops = {
	.enable = clk_audio_pll_frac_enable,
	.disable = clk_audio_pll_frac_disable,
	.recalc_rate = clk_audio_pll_frac_recalc_rate,
	.determine_rate = clk_audio_pll_frac_determine_rate,
	.set_rate = clk_audio_pll_frac_set_rate,
};

static const struct clk_ops audio_pll_pad_ops = {
	.enable = clk_audio_pll_pad_enable,
	.disable = clk_audio_pll_pad_disable,
	.recalc_rate = clk_audio_pll_pad_recalc_rate,
	.round_rate = clk_audio_pll_pad_round_rate,
	.set_rate = clk_audio_pll_pad_set_rate,
};

static const struct clk_ops audio_pll_pmc_ops = {
	.enable = clk_audio_pll_pmc_enable,
	.disable = clk_audio_pll_pmc_disable,
	.recalc_rate = clk_audio_pll_pmc_recalc_rate,
	.round_rate = clk_audio_pll_pmc_round_rate,
	.set_rate = clk_audio_pll_pmc_set_rate,
};

struct clk_hw * __init
at91_clk_register_audio_pll_frac(struct regmap *regmap, const char *name,
				 const char *parent_name)
{
	struct clk_audio_frac *frac_ck;
	struct clk_init_data init = {};
	int ret;

	frac_ck = kzalloc(sizeof(*frac_ck), GFP_KERNEL);
	if (!frac_ck)
		return ERR_PTR(-ENOMEM);

	init.name = name;
	init.ops = &audio_pll_frac_ops;
	init.parent_names = &parent_name;
	init.num_parents = 1;
	init.flags = CLK_SET_RATE_GATE;

	frac_ck->hw.init = &init;
	frac_ck->regmap = regmap;

	ret = clk_hw_register(NULL, &frac_ck->hw);
	if (ret) {
		kfree(frac_ck);
		return ERR_PTR(ret);
	}

	return &frac_ck->hw;
}

struct clk_hw * __init
at91_clk_register_audio_pll_pad(struct regmap *regmap, const char *name,
				const char *parent_name)
{
	struct clk_audio_pad *apad_ck;
	struct clk_init_data init;
	int ret;

	apad_ck = kzalloc(sizeof(*apad_ck), GFP_KERNEL);
	if (!apad_ck)
		return ERR_PTR(-ENOMEM);

	init.name = name;
	init.ops = &audio_pll_pad_ops;
	init.parent_names = &parent_name;
	init.num_parents = 1;
	init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE |
		CLK_SET_RATE_PARENT;

	apad_ck->hw.init = &init;
	apad_ck->regmap = regmap;

	ret = clk_hw_register(NULL, &apad_ck->hw);
	if (ret) {
		kfree(apad_ck);
		return ERR_PTR(ret);
	}

	return &apad_ck->hw;
}

struct clk_hw * __init
at91_clk_register_audio_pll_pmc(struct regmap *regmap, const char *name,
				const char *parent_name)
{
	struct clk_audio_pmc *apmc_ck;
	struct clk_init_data init;
	int ret;

	apmc_ck = kzalloc(sizeof(*apmc_ck), GFP_KERNEL);
	if (!apmc_ck)
		return ERR_PTR(-ENOMEM);

	init.name = name;
	init.ops = &audio_pll_pmc_ops;
	init.parent_names = &parent_name;
	init.num_parents = 1;
	init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE |
		CLK_SET_RATE_PARENT;

	apmc_ck->hw.init = &init;
	apmc_ck->regmap = regmap;

	ret = clk_hw_register(NULL, &apmc_ck->hw);
	if (ret) {
		kfree(apmc_ck);
		return ERR_PTR(ret);
	}

	return &apmc_ck->hw;
}