clk: qcom: add vdd-class voltage regulator voting support

obj-$(CONFIG_COMMON_CLK_QCOM) += clk-qcom.o

clk-qcom-y += common.o

clk-qcom-y += vdd-class.o

clk-qcom-y += clk-regmap.o

clk-qcom-y += clk-alpha-pll.o

clk-qcom-y += clk-pll.o

// SPDX-License-Identifier: GPL-2.0-only

/* Copyright (c) 2019, The Linux Foundation. All rights reserved. */

#include <linux/clk-provider.h>

#include <linux/kernel.h>

#include <linux/regulator/consumer.h>

#include "vdd-class.h"

/*

 * Aggregate the vdd_class level votes and call regulator framework functions

 * to enforce the highest vote.

 */

static int clk_aggregate_vdd(struct clk_vdd_class *vdd_class)

{

	struct regulator **r = vdd_class->regulator;

	int level, ret, i, ignore;

	int *uv = vdd_class->vdd_uv;

	int n_reg = vdd_class->num_regulators;

	int cur_lvl = vdd_class->cur_level;

	int max_lvl = vdd_class->num_levels - 1;

	int cur_base = cur_lvl * n_reg;

	int new_base;

	/* aggregate votes */

	for (level = max_lvl; level > 0; level--)

		if (vdd_class->level_votes[level])

			break;

	if (level == cur_lvl)

		return 0;

	new_base = level * n_reg;

	for (i = 0; i < vdd_class->num_regulators; i++) {

		pr_debug("Set voltage level %d\n", uv[new_base + i]);

		ret = regulator_set_voltage(r[i], uv[new_base + i], INT_MAX);

		if (ret)

			goto set_voltage_fail;

		if (cur_lvl == 0 || cur_lvl == vdd_class->num_levels)

			ret = regulator_enable(r[i]);

		else if (level == 0)

			ret = regulator_disable(r[i]);

		if (ret)

			goto enable_disable_fail;

	}

	vdd_class->cur_level = level;

	return 0;

enable_disable_fail:

	regulator_set_voltage(r[i], uv[cur_base + i], INT_MAX);

set_voltage_fail:

	for (i--; i >= 0; i--) {

		regulator_set_voltage(r[i], uv[cur_base + i], INT_MAX);

		if (cur_lvl == 0 || cur_lvl == vdd_class->num_levels)

			regulator_disable(r[i]);

		else if (level == 0)

			ignore = regulator_enable(r[i]);

	}

	return ret;

}

/**

 * clk_vote_vdd_level - Add a vote for a given voltage level

 * @vdd_data:	vdd_class data for the clock

 * @level:	voltage level to add a vote for

 *

 * Add a regulator framework voltage request for the vdd_class regulator(s)

 * by decrementing the reference count for a given voltage level. This ensures

 * that the supply regulator is allowed to potentially lower its voltage after

 * re-aggregating overall voltage requests.

 *

 * Returns 0 on success, -EERROR otherwise.

 */

int clk_vote_vdd_level(struct clk_vdd_class_data *vdd_data, int level)

{

	struct clk_vdd_class *vdd_class = vdd_data->vdd_class;

	int ret = 0;

	if (level >= vdd_class->num_levels)

		return -EINVAL;

	vdd_class->level_votes[level]++;

	ret = clk_aggregate_vdd(vdd_class);

	if (ret)

		vdd_class->level_votes[level]--;

	return ret;

}

EXPORT_SYMBOL(clk_vote_vdd_level);

/**

 * clk_unvote_vdd_level - Remove a vote for a given voltage level

 * @vdd_data:	vdd_class data for the clock

 * @level:	voltage level to remove a vote for

 *

 * Removes a regulator framework voltage request for the vdd_class regulator(s)

 * by incrementing the reference count for a given voltage level. This ensures

 * that the supply regulator is outputting at least at the requested level.

 *

 * Returns 0 on success, -EERROR otherwise.

 */

int clk_unvote_vdd_level(struct clk_vdd_class_data *vdd_data, int level)

{

	struct clk_vdd_class *vdd_class = vdd_data->vdd_class;

	int ret = 0;

	if (level >= vdd_class->num_levels)

		return -EINVAL;

	if (WARN(!vdd_class->level_votes[level],

			"Reference counts are incorrect for %s level %d\n",

			vdd_class->class_name, level)) {

		return -EINVAL;

	}

	vdd_class->level_votes[level]--;

	ret = clk_aggregate_vdd(vdd_class);

	if (ret)

		vdd_class->level_votes[level]++;

	return ret;

}

EXPORT_SYMBOL(clk_unvote_vdd_level);

/**

 * clk_find_vdd_level - Find the voltage level required for a given clock rate.

 * @hw:		clk_hw pointer of clock being voted on

 * @vdd_data:	vdd_class data for the clock

 * @rate:	Clock rate in Hz to vote for

 *

 * Finds the matching required voltage level for a rate from a list

 * of well characterized frequency to voltage points for a given clock.

 *

 * Returns 0 on success, -EERROR otherwise.

 */

int clk_find_vdd_level(struct clk_hw *hw,

				struct clk_vdd_class_data *vdd_data,

				unsigned long rate)

{

	int level;

	/*

	 * For certain PLLs, due to the limitation in the bits allocated for

	 * programming the fractional divider, the actual rate of the PLL will

	 * be slightly higher than the requested rate (in the order of several

	 * Hz). To accommodate this difference, convert the FMAX rate and the

	 * clock frequency to KHz and use that for deriving the voltage level.

	 */

	for (level = 0; level < vdd_data->num_rate_max; level++)

		if (DIV_ROUND_CLOSEST(rate, 1000) <=

		    DIV_ROUND_CLOSEST(vdd_data->rate_max[level], 1000) &&

		     vdd_data->rate_max[level] > 0)

			break;

	if (level == vdd_data->num_rate_max) {

		pr_err("Rate %lu for %s is greater than highest Fmax\n",

			rate, clk_hw_get_name(hw));

		return -EINVAL;

	}

	return level;

}

EXPORT_SYMBOL(clk_find_vdd_level);

/* SPDX-License-Identifier: GPL-2.0-only */

/* Copyright (c) 2019, The Linux Foundation. All rights reserved. */

#ifndef __QCOM_CLK_VDD_CLASS_H__

#define __QCOM_CLK_VDD_CLASS_H__

#include <linux/regulator/consumer.h>

/**

 * struct clk_vdd_class - Voltage scaling class

 *

 * @class_name:		name of the class

 * @regulator:		array of regulators

 * @num_regulators:	size of regulator array

 * @vdd_uv:		sorted 2D array of legal voltage settings. Indexed by

 *			level, then regulator

 * @level_votes:	array of votes for each level

 * @num_levels:		size of level_votes array

 * @cur_level:		the currently set voltage level

 */

struct clk_vdd_class {

	const char		*class_name;

	struct regulator	**regulator;

	int			num_regulators;

	int			*vdd_uv;

	int			*level_votes;

	int			num_levels;

	int			cur_level;

};

/**

 * struct clk_vdd_class_data - per-clock vdd_class rate data

 *

 * @vdd_class:		voltage scaling requirement class

 * @rate_max:		array of maximum clock rate in Hz supported at each

 *			voltage level, indexed by voltage level

 * @num_rate_max:	size of rate_max array

 * @vdd_rate:		cached rate of current vdd vote

 */

struct clk_vdd_class_data {

	struct clk_vdd_class	*vdd_class;

	unsigned long		*rate_max;

	int			num_rate_max;

	int			vdd_level;

};

#define DEFINE_VDD_REGULATORS(_name, _num_levels, _num_regulators, _vdd_uv) \

	struct clk_vdd_class _name = { \

		.class_name = #_name, \

		.vdd_uv = _vdd_uv, \

		.regulator = (struct regulator * [_num_regulators]) {}, \

		.num_regulators = _num_regulators, \

		.level_votes = (int [_num_levels]) {}, \

		.num_levels = _num_levels, \

		.cur_level = _num_levels, \

	}

#define DEFINE_VDD_REGS_INIT(_name, _num_regulators) \

	struct clk_vdd_class _name = { \

		.class_name = #_name, \

		.regulator = (struct regulator * [_num_regulators]) {}, \

		.num_regulators = _num_regulators, \

	}

int clk_find_vdd_level(struct clk_hw *hw, struct clk_vdd_class_data *vdd_data,

				unsigned long rate);

int clk_vote_vdd_level(struct clk_vdd_class_data *vdd_class, int level);

int clk_unvote_vdd_level(struct clk_vdd_class_data *vdd_class, int level);

#endif