power: qcom-step-chg: Add a new file for step-charging

/* Copyright (c) 2017 The Linux Foundation. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 and

 * only version 2 as published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */

#define pr_fmt(fmt) "QCOM-STEPCHG: %s: " fmt, __func__

#include <linux/delay.h>

#include <linux/module.h>

#include <linux/power_supply.h>

#include <linux/slab.h>

#include <linux/pmic-voter.h>

#include "step-chg-jeita.h"

#define MAX_STEP_CHG_ENTRIES	8

#define STEP_CHG_VOTER		"STEP_CHG_VOTER"

#define STATUS_CHANGE_VOTER	"STATUS_CHANGE_VOTER"

#define is_between(left, right, value) \

		(((left) >= (right) && (left) >= (value) \

			&& (value) >= (right)) \

		|| ((left) <= (right) && (left) <= (value) \

			&& (value) <= (right)))

struct step_chg_data {

	u32 vbatt_soc_low;

	u32 vbatt_soc_high;

	u32 fcc_ua;

};

struct step_chg_cfg {

	u32 psy_prop;

	char *prop_name;

	struct step_chg_data cfg[MAX_STEP_CHG_ENTRIES];

};

struct step_chg_info {

	ktime_t			last_update_time;

	bool			step_chg_enable;

	struct votable		*fcc_votable;

	struct wakeup_source	*step_chg_ws;

	struct power_supply	*batt_psy;

	struct delayed_work	status_change_work;

	struct notifier_block	nb;

};

static struct step_chg_info *the_chip;

/*

 * Step Charging Configuration

 * Update the table based on the battery profile

 * Supports VBATT and SOC based source

 */

static struct step_chg_cfg step_chg_config = {

	.psy_prop  = POWER_SUPPLY_PROP_VOLTAGE_NOW,

	.prop_name = "VBATT",

	.cfg	 = {

		/* VBAT_LOW	VBAT_HIGH	FCC */

		{3600000,	4000000,	3000000},

		{4000000,	4200000,	2800000},

		{4200000,	4400000,	2000000},

	},

/*

 *	SOC STEP-CHG configuration example.

 *

 *	.psy_prop = POWER_SUPPLY_PROP_CAPACITY,

 *	.prop_name = "SOC",

 *	.cfg	= {

 *		//SOC_LOW	SOC_HIGH	FCC

 *		{20,		70,		3000000},

 *		{70,		90,		2750000},

 *		{90,		100,		2500000},

 *	},

 */

};

static bool is_batt_available(struct step_chg_info *chip)

{

	if (!chip->batt_psy)

		chip->batt_psy = power_supply_get_by_name("battery");

	if (!chip->batt_psy)

		return false;

	return true;

}

static int get_fcc(int threshold)

{

	int i;

	for (i = 0; i < MAX_STEP_CHG_ENTRIES; i++)

		if (is_between(step_chg_config.cfg[i].vbatt_soc_low,

			step_chg_config.cfg[i].vbatt_soc_high, threshold))

			return step_chg_config.cfg[i].fcc_ua;

	return -ENODATA;

}

static int handle_step_chg_config(struct step_chg_info *chip)

{

	union power_supply_propval pval = {0, };

	int rc = 0, fcc_ua = 0;

	rc = power_supply_get_property(chip->batt_psy,

		POWER_SUPPLY_PROP_STEP_CHARGING_ENABLED, &pval);

	if (rc < 0)

		chip->step_chg_enable = 0;

	else

		chip->step_chg_enable = pval.intval;

	if (!chip->step_chg_enable) {

		if (chip->fcc_votable)

			vote(chip->fcc_votable, STEP_CHG_VOTER, false, 0);

		return 0;

	}

	rc = power_supply_get_property(chip->batt_psy,

				step_chg_config.psy_prop, &pval);

	if (rc < 0) {

		pr_err("Couldn't read %s property rc=%d\n",

				step_chg_config.prop_name, rc);

		return rc;

	}

	chip->fcc_votable = find_votable("FCC");

	if (!chip->fcc_votable)

		return -EINVAL;

	fcc_ua = get_fcc(pval.intval);

	if (fcc_ua < 0) {

		/* remove the vote if no step-based fcc is found */

		vote(chip->fcc_votable, STEP_CHG_VOTER, false, 0);

		return 0;

	}

	vote(chip->fcc_votable, STEP_CHG_VOTER, true, fcc_ua);

	pr_debug("%s = %d Step-FCC = %duA\n",

		step_chg_config.prop_name, pval.intval, fcc_ua);

	return 0;

}

#define STEP_CHG_HYSTERISIS_DELAY_US		5000000 /* 5 secs */

static void status_change_work(struct work_struct *work)

{

	struct step_chg_info *chip = container_of(work,

			struct step_chg_info, status_change_work.work);

	int rc = 0;

	u64 elapsed_us;

	elapsed_us = ktime_us_delta(ktime_get(), chip->last_update_time);

	if (elapsed_us < STEP_CHG_HYSTERISIS_DELAY_US)

		goto release_ws;

	if (!is_batt_available(chip))

		goto release_ws;

	rc = handle_step_chg_config(chip);

	if (rc < 0)

		goto release_ws;

	chip->last_update_time = ktime_get();

release_ws:

	__pm_relax(chip->step_chg_ws);

}

static int step_chg_notifier_call(struct notifier_block *nb,

		unsigned long ev, void *v)

{

	struct power_supply *psy = v;

	struct step_chg_info *chip = container_of(nb, struct step_chg_info, nb);

	if (ev != PSY_EVENT_PROP_CHANGED)

		return NOTIFY_OK;

	if ((strcmp(psy->desc->name, "battery") == 0)) {

		__pm_stay_awake(chip->step_chg_ws);

		schedule_delayed_work(&chip->status_change_work, 0);

	}

	return NOTIFY_OK;

}

static int step_chg_register_notifier(struct step_chg_info *chip)

{

	int rc;

	chip->nb.notifier_call = step_chg_notifier_call;

	rc = power_supply_reg_notifier(&chip->nb);

	if (rc < 0) {

		pr_err("Couldn't register psy notifier rc = %d\n", rc);

		return rc;

	}

	return 0;

}

int qcom_step_chg_init(bool step_chg_enable)

{

	int rc;

	struct step_chg_info *chip;

	if (the_chip) {

		pr_err("Already initialized\n");

		return -EINVAL;

	}

	chip = kzalloc(sizeof(*chip), GFP_KERNEL);

	if (!chip)

		return -ENOMEM;

	chip->step_chg_ws = wakeup_source_register("qcom-step-chg");

	if (!chip->step_chg_ws) {

		rc = -EINVAL;

		goto cleanup;

	}

	chip->step_chg_enable = step_chg_enable;

	if (step_chg_enable && (!step_chg_config.psy_prop ||

				!step_chg_config.prop_name)) {

		/* fail if step-chg configuration is invalid */

		pr_err("Step-chg configuration not defined - fail\n");

		return -ENODATA;

	}

	INIT_DELAYED_WORK(&chip->status_change_work, status_change_work);

	rc = step_chg_register_notifier(chip);

	if (rc < 0) {

		pr_err("Couldn't register psy notifier rc = %d\n", rc);

		goto release_wakeup_source;

	}

	the_chip = chip;

	if (step_chg_enable)

		pr_info("Step charging enabled. Using %s source\n",

				step_chg_config.prop_name);

	return 0;

release_wakeup_source:

	wakeup_source_unregister(chip->step_chg_ws);

cleanup:

	kfree(chip);

	return rc;

}

void qcom_step_chg_deinit(void)

{

	struct step_chg_info *chip = the_chip;

	if (!chip)

		return;

	cancel_delayed_work_sync(&chip->status_change_work);

	power_supply_unreg_notifier(&chip->nb);

	wakeup_source_unregister(chip->step_chg_ws);

	the_chip = NULL;

	kfree(chip);

}

/* Copyright (c) 2017 The Linux Foundation. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 and

 * only version 2 as published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */

#ifndef __STEP_CHG_H__

#define __STEP_CHG_H__

int qcom_step_chg_init(bool);

void qcom_step_chg_deinit(void);

#endif /* __STEP_CHG_H__ */