/*
 * Battery power supply driver for X-Powers AXP20X and AXP22X PMICs
 *
 * Copyright 2016 Free Electrons NextThing Co.
 *	Quentin Schulz <quentin.schulz@free-electrons.com>
 *
 * This driver is based on a previous upstreaming attempt by:
 *	Bruno Prémont <bonbons@linux-vserver.org>
 *
 * 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.
 *
 * 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.
 */

#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/iio/iio.h>
#include <linux/iio/consumer.h>
#include <linux/mfd/axp20x.h>

#define AXP20X_PWR_STATUS_BAT_CHARGING	BIT(2)

#define AXP20X_PWR_OP_BATT_PRESENT	BIT(5)
#define AXP20X_PWR_OP_BATT_ACTIVATED	BIT(3)

#define AXP209_FG_PERCENT		GENMASK(6, 0)
#define AXP22X_FG_VALID			BIT(7)

#define AXP20X_CHRG_CTRL1_TGT_VOLT	GENMASK(6, 5)
#define AXP20X_CHRG_CTRL1_TGT_4_1V	(0 << 5)
#define AXP20X_CHRG_CTRL1_TGT_4_15V	(1 << 5)
#define AXP20X_CHRG_CTRL1_TGT_4_2V	(2 << 5)
#define AXP20X_CHRG_CTRL1_TGT_4_36V	(3 << 5)

#define AXP22X_CHRG_CTRL1_TGT_4_22V	(1 << 5)
#define AXP22X_CHRG_CTRL1_TGT_4_24V	(3 << 5)

#define AXP20X_CHRG_CTRL1_TGT_CURR	GENMASK(3, 0)

#define AXP20X_V_OFF_MASK		GENMASK(2, 0)

struct axp20x_batt_ps {
	struct regmap *regmap;
	struct power_supply *batt;
	struct device *dev;
	struct iio_channel *batt_chrg_i;
	struct iio_channel *batt_dischrg_i;
	struct iio_channel *batt_v;
	/* Maximum constant charge current */
	unsigned int max_ccc;
	u8 axp_id;
};

static int axp20x_battery_get_max_voltage(struct axp20x_batt_ps *axp20x_batt,
					  int *val)
{
	int ret, reg;

	ret = regmap_read(axp20x_batt->regmap, AXP20X_CHRG_CTRL1, &reg);
	if (ret)
		return ret;

	switch (reg & AXP20X_CHRG_CTRL1_TGT_VOLT) {
	case AXP20X_CHRG_CTRL1_TGT_4_1V:
		*val = 4100000;
		break;
	case AXP20X_CHRG_CTRL1_TGT_4_15V:
		*val = 4150000;
		break;
	case AXP20X_CHRG_CTRL1_TGT_4_2V:
		*val = 4200000;
		break;
	case AXP20X_CHRG_CTRL1_TGT_4_36V:
		*val = 4360000;
		break;
	default:
		return -EINVAL;
	}

	return 0;
}

static int axp22x_battery_get_max_voltage(struct axp20x_batt_ps *axp20x_batt,
					  int *val)
{
	int ret, reg;

	ret = regmap_read(axp20x_batt->regmap, AXP20X_CHRG_CTRL1, &reg);
	if (ret)
		return ret;

	switch (reg & AXP20X_CHRG_CTRL1_TGT_VOLT) {
	case AXP20X_CHRG_CTRL1_TGT_4_1V:
		*val = 4100000;
		break;
	case AXP20X_CHRG_CTRL1_TGT_4_2V:
		*val = 4200000;
		break;
	case AXP22X_CHRG_CTRL1_TGT_4_22V:
		*val = 4220000;
		break;
	case AXP22X_CHRG_CTRL1_TGT_4_24V:
		*val = 4240000;
		break;
	default:
		return -EINVAL;
	}

	return 0;
}

static void raw_to_constant_charge_current(struct axp20x_batt_ps *axp, int *val)
{
	if (axp->axp_id == AXP209_ID)
		*val = *val * 100000 + 300000;
	else
		*val = *val * 150000 + 300000;
}

static void constant_charge_current_to_raw(struct axp20x_batt_ps *axp, int *val)
{
	if (axp->axp_id == AXP209_ID)
		*val = (*val - 300000) / 100000;
	else
		*val = (*val - 300000) / 150000;
}

static int axp20x_get_constant_charge_current(struct axp20x_batt_ps *axp,
					      int *val)
{
	int ret;

	ret = regmap_read(axp->regmap, AXP20X_CHRG_CTRL1, val);
	if (ret)
		return ret;

	*val &= AXP20X_CHRG_CTRL1_TGT_CURR;

	raw_to_constant_charge_current(axp, val);

	return 0;
}

static int axp20x_battery_get_prop(struct power_supply *psy,
				   enum power_supply_property psp,
				   union power_supply_propval *val)
{
	struct axp20x_batt_ps *axp20x_batt = power_supply_get_drvdata(psy);
	struct iio_channel *chan;
	int ret = 0, reg, val1;

	switch (psp) {
	case POWER_SUPPLY_PROP_PRESENT:
	case POWER_SUPPLY_PROP_ONLINE:
		ret = regmap_read(axp20x_batt->regmap, AXP20X_PWR_OP_MODE,
				  &reg);
		if (ret)
			return ret;

		val->intval = !!(reg & AXP20X_PWR_OP_BATT_PRESENT);
		break;

	case POWER_SUPPLY_PROP_STATUS:
		ret = regmap_read(axp20x_batt->regmap, AXP20X_PWR_INPUT_STATUS,
				  &reg);
		if (ret)
			return ret;

		if (reg & AXP20X_PWR_STATUS_BAT_CHARGING) {
			val->intval = POWER_SUPPLY_STATUS_CHARGING;
			return 0;
		}

		ret = iio_read_channel_processed(axp20x_batt->batt_dischrg_i,
						 &val1);
		if (ret)
			return ret;

		if (val1) {
			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
			return 0;
		}

		ret = regmap_read(axp20x_batt->regmap, AXP20X_FG_RES, &val1);
		if (ret)
			return ret;

		/*
		 * Fuel Gauge data takes 7 bits but the stored value seems to be
		 * directly the raw percentage without any scaling to 7 bits.
		 */
		if ((val1 & AXP209_FG_PERCENT) == 100)
			val->intval = POWER_SUPPLY_STATUS_FULL;
		else
			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
		break;

	case POWER_SUPPLY_PROP_HEALTH:
		ret = regmap_read(axp20x_batt->regmap, AXP20X_PWR_OP_MODE,
				  &val1);
		if (ret)
			return ret;

		if (val1 & AXP20X_PWR_OP_BATT_ACTIVATED) {
			val->intval = POWER_SUPPLY_HEALTH_DEAD;
			return 0;
		}

		val->intval = POWER_SUPPLY_HEALTH_GOOD;
		break;

	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
		ret = axp20x_get_constant_charge_current(axp20x_batt,
							 &val->intval);
		if (ret)
			return ret;
		break;

	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
		val->intval = axp20x_batt->max_ccc;
		break;

	case POWER_SUPPLY_PROP_CURRENT_NOW:
		ret = regmap_read(axp20x_batt->regmap, AXP20X_PWR_INPUT_STATUS,
				  &reg);
		if (ret)
			return ret;

		if (reg & AXP20X_PWR_STATUS_BAT_CHARGING)
			chan = axp20x_batt->batt_chrg_i;
		else
			chan = axp20x_batt->batt_dischrg_i;

		ret = iio_read_channel_processed(chan, &val->intval);
		if (ret)
			return ret;

		/* IIO framework gives mA but Power Supply framework gives uA */
		val->intval *= 1000;
		break;

	case POWER_SUPPLY_PROP_CAPACITY:
		/* When no battery is present, return capacity is 100% */
		ret = regmap_read(axp20x_batt->regmap, AXP20X_PWR_OP_MODE,
				  &reg);
		if (ret)
			return ret;

		if (!(reg & AXP20X_PWR_OP_BATT_PRESENT)) {
			val->intval = 100;
			return 0;
		}

		ret = regmap_read(axp20x_batt->regmap, AXP20X_FG_RES, &reg);
		if (ret)
			return ret;

		if (axp20x_batt->axp_id == AXP221_ID &&
		    !(reg & AXP22X_FG_VALID))
			return -EINVAL;

		/*
		 * Fuel Gauge data takes 7 bits but the stored value seems to be
		 * directly the raw percentage without any scaling to 7 bits.
		 */
		val->intval = reg & AXP209_FG_PERCENT;
		break;

	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
		if (axp20x_batt->axp_id == AXP209_ID)
			return axp20x_battery_get_max_voltage(axp20x_batt,
							      &val->intval);
		return axp22x_battery_get_max_voltage(axp20x_batt,
						      &val->intval);

	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
		ret = regmap_read(axp20x_batt->regmap, AXP20X_V_OFF, &reg);
		if (ret)
			return ret;

		val->intval = 2600000 + 100000 * (reg & AXP20X_V_OFF_MASK);
		break;

	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
		ret = iio_read_channel_processed(axp20x_batt->batt_v,
						 &val->intval);
		if (ret)
			return ret;

		/* IIO framework gives mV but Power Supply framework gives uV */
		val->intval *= 1000;
		break;

	default:
		return -EINVAL;
	}

	return 0;
}

static int axp20x_battery_set_max_voltage(struct axp20x_batt_ps *axp20x_batt,
					  int val)
{
	switch (val) {
	case 4100000:
		val = AXP20X_CHRG_CTRL1_TGT_4_1V;
		break;

	case 4150000:
		if (axp20x_batt->axp_id == AXP221_ID)
			return -EINVAL;

		val = AXP20X_CHRG_CTRL1_TGT_4_15V;
		break;

	case 4200000:
		val = AXP20X_CHRG_CTRL1_TGT_4_2V;
		break;

	default:
		/*
		 * AXP20x max voltage can be set to 4.36V and AXP22X max voltage
		 * can be set to 4.22V and 4.24V, but these voltages are too
		 * high for Lithium based batteries (AXP PMICs are supposed to
		 * be used with these kinds of battery).
		 */
		return -EINVAL;
	}

	return regmap_update_bits(axp20x_batt->regmap, AXP20X_CHRG_CTRL1,
				  AXP20X_CHRG_CTRL1_TGT_VOLT, val);
}

static int axp20x_set_constant_charge_current(struct axp20x_batt_ps *axp_batt,
					      int charge_current)
{
	if (charge_current > axp_batt->max_ccc)
		return -EINVAL;

	constant_charge_current_to_raw(axp_batt, &charge_current);

	if (charge_current > AXP20X_CHRG_CTRL1_TGT_CURR || charge_current < 0)
		return -EINVAL;

	return regmap_update_bits(axp_batt->regmap, AXP20X_CHRG_CTRL1,
				  AXP20X_CHRG_CTRL1_TGT_CURR, charge_current);
}

static int axp20x_set_max_constant_charge_current(struct axp20x_batt_ps *axp,
						  int charge_current)
{
	bool lower_max = false;

	constant_charge_current_to_raw(axp, &charge_current);

	if (charge_current > AXP20X_CHRG_CTRL1_TGT_CURR || charge_current < 0)
		return -EINVAL;

	raw_to_constant_charge_current(axp, &charge_current);

	if (charge_current > axp->max_ccc)
		dev_warn(axp->dev,
			 "Setting max constant charge current higher than previously defined. Note that increasing the constant charge current may damage your battery.\n");
	else
		lower_max = true;

	axp->max_ccc = charge_current;

	if (lower_max) {
		int current_cc;

		axp20x_get_constant_charge_current(axp, &current_cc);
		if (current_cc > charge_current)
			axp20x_set_constant_charge_current(axp, charge_current);
	}

	return 0;
}
static int axp20x_set_voltage_min_design(struct axp20x_batt_ps *axp_batt,
					 int min_voltage)
{
	int val1 = (min_voltage - 2600000) / 100000;

	if (val1 < 0 || val1 > AXP20X_V_OFF_MASK)
		return -EINVAL;

	return regmap_update_bits(axp_batt->regmap, AXP20X_V_OFF,
				  AXP20X_V_OFF_MASK, val1);
}

static int axp20x_battery_set_prop(struct power_supply *psy,
				   enum power_supply_property psp,
				   const union power_supply_propval *val)
{
	struct axp20x_batt_ps *axp20x_batt = power_supply_get_drvdata(psy);

	switch (psp) {
	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
		return axp20x_set_voltage_min_design(axp20x_batt, val->intval);

	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
		return axp20x_battery_set_max_voltage(axp20x_batt, val->intval);

	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
		return axp20x_set_constant_charge_current(axp20x_batt,
							  val->intval);
	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
		return axp20x_set_max_constant_charge_current(axp20x_batt,
							      val->intval);

	default:
		return -EINVAL;
	}
}

static enum power_supply_property axp20x_battery_props[] = {
	POWER_SUPPLY_PROP_PRESENT,
	POWER_SUPPLY_PROP_ONLINE,
	POWER_SUPPLY_PROP_STATUS,
	POWER_SUPPLY_PROP_VOLTAGE_NOW,
	POWER_SUPPLY_PROP_CURRENT_NOW,
	POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT,
	POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX,
	POWER_SUPPLY_PROP_HEALTH,
	POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
	POWER_SUPPLY_PROP_CAPACITY,
};

static int axp20x_battery_prop_writeable(struct power_supply *psy,
					 enum power_supply_property psp)
{
	return psp == POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN ||
	       psp == POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN ||
	       psp == POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT ||
	       psp == POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX;
}

static const struct power_supply_desc axp20x_batt_ps_desc = {
	.name = "axp20x-battery",
	.type = POWER_SUPPLY_TYPE_BATTERY,
	.properties = axp20x_battery_props,
	.num_properties = ARRAY_SIZE(axp20x_battery_props),
	.property_is_writeable = axp20x_battery_prop_writeable,
	.get_property = axp20x_battery_get_prop,
	.set_property = axp20x_battery_set_prop,
};

static const struct of_device_id axp20x_battery_ps_id[] = {
	{
		.compatible = "x-powers,axp209-battery-power-supply",
		.data = (void *)AXP209_ID,
	}, {
		.compatible = "x-powers,axp221-battery-power-supply",
		.data = (void *)AXP221_ID,
	}, { /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, axp20x_battery_ps_id);

static int axp20x_power_probe(struct platform_device *pdev)
{
	struct axp20x_batt_ps *axp20x_batt;
	struct power_supply_config psy_cfg = {};
	struct power_supply_battery_info info;

	if (!of_device_is_available(pdev->dev.of_node))
		return -ENODEV;

	axp20x_batt = devm_kzalloc(&pdev->dev, sizeof(*axp20x_batt),
				   GFP_KERNEL);
	if (!axp20x_batt)
		return -ENOMEM;

	axp20x_batt->dev = &pdev->dev;

	axp20x_batt->batt_v = devm_iio_channel_get(&pdev->dev, "batt_v");
	if (IS_ERR(axp20x_batt->batt_v)) {
		if (PTR_ERR(axp20x_batt->batt_v) == -ENODEV)
			return -EPROBE_DEFER;
		return PTR_ERR(axp20x_batt->batt_v);
	}

	axp20x_batt->batt_chrg_i = devm_iio_channel_get(&pdev->dev,
							"batt_chrg_i");
	if (IS_ERR(axp20x_batt->batt_chrg_i)) {
		if (PTR_ERR(axp20x_batt->batt_chrg_i) == -ENODEV)
			return -EPROBE_DEFER;
		return PTR_ERR(axp20x_batt->batt_chrg_i);
	}

	axp20x_batt->batt_dischrg_i = devm_iio_channel_get(&pdev->dev,
							   "batt_dischrg_i");
	if (IS_ERR(axp20x_batt->batt_dischrg_i)) {
		if (PTR_ERR(axp20x_batt->batt_dischrg_i) == -ENODEV)
			return -EPROBE_DEFER;
		return PTR_ERR(axp20x_batt->batt_dischrg_i);
	}

	axp20x_batt->regmap = dev_get_regmap(pdev->dev.parent, NULL);
	platform_set_drvdata(pdev, axp20x_batt);

	psy_cfg.drv_data = axp20x_batt;
	psy_cfg.of_node = pdev->dev.of_node;

	axp20x_batt->axp_id = (uintptr_t)of_device_get_match_data(&pdev->dev);

	axp20x_batt->batt = devm_power_supply_register(&pdev->dev,
						       &axp20x_batt_ps_desc,
						       &psy_cfg);
	if (IS_ERR(axp20x_batt->batt)) {
		dev_err(&pdev->dev, "failed to register power supply: %ld\n",
			PTR_ERR(axp20x_batt->batt));
		return PTR_ERR(axp20x_batt->batt);
	}

	if (!power_supply_get_battery_info(axp20x_batt->batt, &info)) {
		int vmin = info.voltage_min_design_uv;
		int ccc = info.constant_charge_current_max_ua;

		if (vmin > 0 && axp20x_set_voltage_min_design(axp20x_batt,
							      vmin))
			dev_err(&pdev->dev,
				"couldn't set voltage_min_design\n");

		/* Set max to unverified value to be able to set CCC */
		axp20x_batt->max_ccc = ccc;

		if (ccc <= 0 || axp20x_set_constant_charge_current(axp20x_batt,
								   ccc)) {
			dev_err(&pdev->dev,
				"couldn't set constant charge current from DT: fallback to minimum value\n");
			ccc = 300000;
			axp20x_batt->max_ccc = ccc;
			axp20x_set_constant_charge_current(axp20x_batt, ccc);
		}
	}

	/*
	 * Update max CCC to a valid value if battery info is present or set it
	 * to current register value by default.
	 */
	axp20x_get_constant_charge_current(axp20x_batt,
					   &axp20x_batt->max_ccc);

	return 0;
}

static struct platform_driver axp20x_batt_driver = {
	.probe    = axp20x_power_probe,
	.driver   = {
		.name  = "axp20x-battery-power-supply",
		.of_match_table = axp20x_battery_ps_id,
	},
};

module_platform_driver(axp20x_batt_driver);

MODULE_DESCRIPTION("Battery power supply driver for AXP20X and AXP22X PMICs");
MODULE_AUTHOR("Quentin Schulz <quentin.schulz@free-electrons.com>");
MODULE_LICENSE("GPL");