// SPDX-License-Identifier: GPL-2.0-only
/*
 * PRCMU clock implementation for ux500 platform.
 *
 * Copyright (C) 2012 ST-Ericsson SA
 * Author: Ulf Hansson <ulf.hansson@linaro.org>
 */

#include <linux/clk-provider.h>
#include <linux/mfd/dbx500-prcmu.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/err.h>
#include "clk.h"

#define to_clk_prcmu(_hw) container_of(_hw, struct clk_prcmu, hw)
#define to_clk_prcmu_clkout(_hw) container_of(_hw, struct clk_prcmu_clkout, hw)

struct clk_prcmu {
	struct clk_hw hw;
	u8 cg_sel;
	int opp_requested;
};

struct clk_prcmu_clkout {
	struct clk_hw hw;
	u8 clkout_id;
	u8 source;
	u8 divider;
};

/* PRCMU clock operations. */

static int clk_prcmu_prepare(struct clk_hw *hw)
{
	struct clk_prcmu *clk = to_clk_prcmu(hw);

	return prcmu_request_clock(clk->cg_sel, true);
}

static void clk_prcmu_unprepare(struct clk_hw *hw)
{
	struct clk_prcmu *clk = to_clk_prcmu(hw);
	if (prcmu_request_clock(clk->cg_sel, false))
		pr_err("clk_prcmu: %s failed to disable %s.\n", __func__,
		       clk_hw_get_name(hw));
}

static unsigned long clk_prcmu_recalc_rate(struct clk_hw *hw,
					   unsigned long parent_rate)
{
	struct clk_prcmu *clk = to_clk_prcmu(hw);
	return prcmu_clock_rate(clk->cg_sel);
}

static int clk_prcmu_determine_rate(struct clk_hw *hw,
				    struct clk_rate_request *req)
{
	struct clk_prcmu *clk = to_clk_prcmu(hw);
	req->rate = prcmu_round_clock_rate(clk->cg_sel, req->rate);

	return 0;
}

static int clk_prcmu_set_rate(struct clk_hw *hw, unsigned long rate,
			      unsigned long parent_rate)
{
	struct clk_prcmu *clk = to_clk_prcmu(hw);
	return prcmu_set_clock_rate(clk->cg_sel, rate);
}

static int clk_prcmu_opp_prepare(struct clk_hw *hw)
{
	int err;
	struct clk_prcmu *clk = to_clk_prcmu(hw);

	if (!clk->opp_requested) {
		err = prcmu_qos_add_requirement(PRCMU_QOS_APE_OPP,
						(char *)clk_hw_get_name(hw),
						100);
		if (err) {
			pr_err("clk_prcmu: %s fail req APE OPP for %s.\n",
				__func__, clk_hw_get_name(hw));
			return err;
		}
		clk->opp_requested = 1;
	}

	err = prcmu_request_clock(clk->cg_sel, true);
	if (err) {
		prcmu_qos_remove_requirement(PRCMU_QOS_APE_OPP,
					(char *)clk_hw_get_name(hw));
		clk->opp_requested = 0;
		return err;
	}

	return 0;
}

static void clk_prcmu_opp_unprepare(struct clk_hw *hw)
{
	struct clk_prcmu *clk = to_clk_prcmu(hw);

	if (prcmu_request_clock(clk->cg_sel, false)) {
		pr_err("clk_prcmu: %s failed to disable %s.\n", __func__,
			clk_hw_get_name(hw));
		return;
	}

	if (clk->opp_requested) {
		prcmu_qos_remove_requirement(PRCMU_QOS_APE_OPP,
					(char *)clk_hw_get_name(hw));
		clk->opp_requested = 0;
	}
}

static int clk_prcmu_opp_volt_prepare(struct clk_hw *hw)
{
	int err;
	struct clk_prcmu *clk = to_clk_prcmu(hw);

	if (!clk->opp_requested) {
		err = prcmu_request_ape_opp_100_voltage(true);
		if (err) {
			pr_err("clk_prcmu: %s fail req APE OPP VOLT for %s.\n",
				__func__, clk_hw_get_name(hw));
			return err;
		}
		clk->opp_requested = 1;
	}

	err = prcmu_request_clock(clk->cg_sel, true);
	if (err) {
		prcmu_request_ape_opp_100_voltage(false);
		clk->opp_requested = 0;
		return err;
	}

	return 0;
}

static void clk_prcmu_opp_volt_unprepare(struct clk_hw *hw)
{
	struct clk_prcmu *clk = to_clk_prcmu(hw);

	if (prcmu_request_clock(clk->cg_sel, false)) {
		pr_err("clk_prcmu: %s failed to disable %s.\n", __func__,
			clk_hw_get_name(hw));
		return;
	}

	if (clk->opp_requested) {
		prcmu_request_ape_opp_100_voltage(false);
		clk->opp_requested = 0;
	}
}

static const struct clk_ops clk_prcmu_scalable_ops = {
	.prepare = clk_prcmu_prepare,
	.unprepare = clk_prcmu_unprepare,
	.recalc_rate = clk_prcmu_recalc_rate,
	.determine_rate = clk_prcmu_determine_rate,
	.set_rate = clk_prcmu_set_rate,
};

static const struct clk_ops clk_prcmu_gate_ops = {
	.prepare = clk_prcmu_prepare,
	.unprepare = clk_prcmu_unprepare,
	.recalc_rate = clk_prcmu_recalc_rate,
};

static const struct clk_ops clk_prcmu_scalable_rate_ops = {
	.recalc_rate = clk_prcmu_recalc_rate,
	.determine_rate = clk_prcmu_determine_rate,
	.set_rate = clk_prcmu_set_rate,
};

static const struct clk_ops clk_prcmu_rate_ops = {
	.recalc_rate = clk_prcmu_recalc_rate,
};

static const struct clk_ops clk_prcmu_opp_gate_ops = {
	.prepare = clk_prcmu_opp_prepare,
	.unprepare = clk_prcmu_opp_unprepare,
	.recalc_rate = clk_prcmu_recalc_rate,
};

static const struct clk_ops clk_prcmu_opp_volt_scalable_ops = {
	.prepare = clk_prcmu_opp_volt_prepare,
	.unprepare = clk_prcmu_opp_volt_unprepare,
	.recalc_rate = clk_prcmu_recalc_rate,
	.determine_rate = clk_prcmu_determine_rate,
	.set_rate = clk_prcmu_set_rate,
};

static struct clk_hw *clk_reg_prcmu(const char *name,
				    const char *parent_name,
				    u8 cg_sel,
				    unsigned long rate,
				    unsigned long flags,
				    const struct clk_ops *clk_prcmu_ops)
{
	struct clk_prcmu *clk;
	struct clk_init_data clk_prcmu_init;
	int ret;

	if (!name) {
		pr_err("clk_prcmu: %s invalid arguments passed\n", __func__);
		return ERR_PTR(-EINVAL);
	}

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

	clk->cg_sel = cg_sel;
	clk->opp_requested = 0;
	/* "rate" can be used for changing the initial frequency */
	if (rate)
		prcmu_set_clock_rate(cg_sel, rate);

	clk_prcmu_init.name = name;
	clk_prcmu_init.ops = clk_prcmu_ops;
	clk_prcmu_init.flags = flags;
	clk_prcmu_init.parent_names = (parent_name ? &parent_name : NULL);
	clk_prcmu_init.num_parents = (parent_name ? 1 : 0);
	clk->hw.init = &clk_prcmu_init;

	ret = clk_hw_register(NULL, &clk->hw);
	if (ret)
		goto free_clk;

	return &clk->hw;

free_clk:
	kfree(clk);
	pr_err("clk_prcmu: %s failed to register clk\n", __func__);
	return ERR_PTR(-ENOMEM);
}

struct clk_hw *clk_reg_prcmu_scalable(const char *name,
				      const char *parent_name,
				      u8 cg_sel,
				      unsigned long rate,
				      unsigned long flags)
{
	return clk_reg_prcmu(name, parent_name, cg_sel, rate, flags,
			&clk_prcmu_scalable_ops);
}

struct clk_hw *clk_reg_prcmu_gate(const char *name,
				  const char *parent_name,
				  u8 cg_sel,
				  unsigned long flags)
{
	return clk_reg_prcmu(name, parent_name, cg_sel, 0, flags,
			&clk_prcmu_gate_ops);
}

struct clk_hw *clk_reg_prcmu_scalable_rate(const char *name,
					   const char *parent_name,
					   u8 cg_sel,
					   unsigned long rate,
					   unsigned long flags)
{
	return clk_reg_prcmu(name, parent_name, cg_sel, rate, flags,
			&clk_prcmu_scalable_rate_ops);
}

struct clk_hw *clk_reg_prcmu_rate(const char *name,
				  const char *parent_name,
				  u8 cg_sel,
				  unsigned long flags)
{
	return clk_reg_prcmu(name, parent_name, cg_sel, 0, flags,
			&clk_prcmu_rate_ops);
}

struct clk_hw *clk_reg_prcmu_opp_gate(const char *name,
				      const char *parent_name,
				      u8 cg_sel,
				      unsigned long flags)
{
	return clk_reg_prcmu(name, parent_name, cg_sel, 0, flags,
			&clk_prcmu_opp_gate_ops);
}

struct clk_hw *clk_reg_prcmu_opp_volt_scalable(const char *name,
					       const char *parent_name,
					       u8 cg_sel,
					       unsigned long rate,
					       unsigned long flags)
{
	return clk_reg_prcmu(name, parent_name, cg_sel, rate, flags,
			&clk_prcmu_opp_volt_scalable_ops);
}

/* The clkout (external) clock is special and need special ops */

static int clk_prcmu_clkout_prepare(struct clk_hw *hw)
{
	struct clk_prcmu_clkout *clk = to_clk_prcmu_clkout(hw);

	return prcmu_config_clkout(clk->clkout_id, clk->source, clk->divider);
}

static void clk_prcmu_clkout_unprepare(struct clk_hw *hw)
{
	struct clk_prcmu_clkout *clk = to_clk_prcmu_clkout(hw);
	int ret;

	/* The clkout clock is disabled by dividing by 0 */
	ret = prcmu_config_clkout(clk->clkout_id, clk->source, 0);
	if (ret)
		pr_err("clk_prcmu: %s failed to disable %s\n", __func__,
		       clk_hw_get_name(hw));
}

static unsigned long clk_prcmu_clkout_recalc_rate(struct clk_hw *hw,
						  unsigned long parent_rate)
{
	struct clk_prcmu_clkout *clk = to_clk_prcmu_clkout(hw);

	return (parent_rate / clk->divider);
}

static u8 clk_prcmu_clkout_get_parent(struct clk_hw *hw)
{
	struct clk_prcmu_clkout *clk = to_clk_prcmu_clkout(hw);

	return clk->source;
}

static int clk_prcmu_clkout_set_parent(struct clk_hw *hw, u8 index)
{
	struct clk_prcmu_clkout *clk = to_clk_prcmu_clkout(hw);

	clk->source = index;
	/* Make sure the change reaches the hardware immediately */
	if (clk_hw_is_prepared(hw))
		return clk_prcmu_clkout_prepare(hw);
	return 0;
}

static const struct clk_ops clk_prcmu_clkout_ops = {
	.prepare = clk_prcmu_clkout_prepare,
	.unprepare = clk_prcmu_clkout_unprepare,
	.recalc_rate = clk_prcmu_clkout_recalc_rate,
	.determine_rate = clk_hw_determine_rate_no_reparent,
	.get_parent = clk_prcmu_clkout_get_parent,
	.set_parent = clk_prcmu_clkout_set_parent,
};

struct clk_hw *clk_reg_prcmu_clkout(const char *name,
				    const char * const *parent_names,
				    int num_parents,
				    u8 source, u8 divider)

{
	struct clk_prcmu_clkout *clk;
	struct clk_init_data clk_prcmu_clkout_init;
	u8 clkout_id;
	int ret;

	if (!name) {
		pr_err("clk_prcmu_clkout: %s invalid arguments passed\n", __func__);
		return ERR_PTR(-EINVAL);
	}

	if (!strcmp(name, "clkout1"))
		clkout_id = 0;
	else if (!strcmp(name, "clkout2"))
		clkout_id = 1;
	else {
		pr_err("clk_prcmu_clkout: %s bad clock name\n", __func__);
		return ERR_PTR(-EINVAL);
	}

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

	clk->clkout_id = clkout_id;
	clk->source = source;
	clk->divider = divider;

	clk_prcmu_clkout_init.name = name;
	clk_prcmu_clkout_init.ops = &clk_prcmu_clkout_ops;
	clk_prcmu_clkout_init.flags = CLK_GET_RATE_NOCACHE;
	clk_prcmu_clkout_init.parent_names = parent_names;
	clk_prcmu_clkout_init.num_parents = num_parents;
	clk->hw.init = &clk_prcmu_clkout_init;

	ret = clk_hw_register(NULL, &clk->hw);
	if (ret)
		goto free_clkout;

	return &clk->hw;
free_clkout:
	kfree(clk);
	pr_err("clk_prcmu_clkout: %s failed to register clk\n", __func__);
	return ERR_PTR(-ENOMEM);
}