macsmc_power.c

// SPDX-License-Identifier: GPL-2.0-only OR MIT
/*
 * Apple SMC Power/Battery Management
 * Copyright The Asahi Linux Contributors
 */

#include <linux/ctype.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/mfd/core.h>
#include <linux/mfd/macsmc.h>
#include <linux/power_supply.h>

#define MAX_STRING_LENGTH 256

struct macsmc_power {
	struct device *dev;
	struct apple_smc *smc;

	struct power_supply *batt;
	char model_name[MAX_STRING_LENGTH];
	char serial_number[MAX_STRING_LENGTH];
	char mfg_date[MAX_STRING_LENGTH];

	struct power_supply *ac;

	struct notifier_block nb;
};

#define CHNC_BATTERY_FULL	BIT(0)
#define CHNC_NO_CHARGER		BIT(7)
#define CHNC_NOCHG_CH0C		BIT(14)
#define CHNC_NOCHG_CH0B_CH0K	BIT(15)
#define CHNC_BATTERY_FULL_2	BIT(18)
#define CHNC_BMS_BUSY		BIT(23)
#define CHNC_NOAC_CH0J		BIT(53)
#define CHNC_NOAC_CH0I		BIT(54)

#define CH0R_LOWER_FLAGS	GENMASK(15, 0)
#define CH0R_NOAC_CH0I		BIT(0)
#define CH0R_NOAC_CH0J		BIT(5)
#define CH0R_BMS_BUSY		BIT(8)
#define CH0R_NOAC_CH0K		BIT(9)

#define CH0X_CH0C		BIT(0)
#define CH0X_CH0B		BIT(1)

static int macsmc_battery_get_status(struct macsmc_power *power)
{
	u64 nocharge_flags;
	u32 nopower_flags;
	u16 ac_current;
	int ret;

	/*
	 * Note: there are fallbacks in case some of these SMC keys disappear in the future
	 * or are not present on some machines. We treat the absence of the CHCE/CHCC/BSFC/CHSC
	 * flags as an error, since they are quite fundamental and simple booleans.
	 */

	/*
	 * If power input is inhibited, we are definitely discharging.
	 * However, if the only reason is the BMS is doing a balancing cycle,
	 * go ahead and ignore that one to avoid spooking users.
	 */
	ret = apple_smc_read_u32(power->smc, SMC_KEY(CH0R), &nopower_flags);
	if (!ret && (nopower_flags & CH0R_LOWER_FLAGS & ~CH0R_BMS_BUSY))
		return POWER_SUPPLY_STATUS_DISCHARGING;

	/* If no charger is present, we are definitely discharging. */
	ret = apple_smc_read_flag(power->smc, SMC_KEY(CHCE));
	if (ret < 0)
		return ret;
	else if (!ret)
		return POWER_SUPPLY_STATUS_DISCHARGING;

	/* If AC is not charge capable, we are definitely discharging. */
	ret = apple_smc_read_flag(power->smc, SMC_KEY(CHCC));
	if (ret < 0)
		return ret;
	else if (!ret)
		return POWER_SUPPLY_STATUS_DISCHARGING;

	/*
	 * If the AC input current limit is tiny or 0, we are discharging no matter
	 * how much the BMS believes it can charge.
	 */
	ret = apple_smc_read_u16(power->smc, SMC_KEY(AC-i), &ac_current);
	if (!ret && ac_current < 100)
		return POWER_SUPPLY_STATUS_DISCHARGING;

	/* If the battery is full, report it as such. */
	ret = apple_smc_read_flag(power->smc, SMC_KEY(BSFC));
	if (ret < 0)
		return ret;
	else if (ret)
		return POWER_SUPPLY_STATUS_FULL;

	/* If there are reasons we aren't charging... */
	ret = apple_smc_read_u64(power->smc, SMC_KEY(CHNC), &nocharge_flags);
	if (!ret) {
		/* Perhaps the battery is full after all */
		if (nocharge_flags & CHNC_BATTERY_FULL)
			return POWER_SUPPLY_STATUS_FULL;
		/* Or maybe the BMS is just busy doing something, if so call it charging anyway */
		else if (nocharge_flags == CHNC_BMS_BUSY)
			return POWER_SUPPLY_STATUS_CHARGING;
		/* If we have other reasons we aren't charging, say we aren't */
		else if (nocharge_flags)
			return POWER_SUPPLY_STATUS_NOT_CHARGING;
		/* Else we're either charging or about to charge */
		else
			return POWER_SUPPLY_STATUS_CHARGING;
	}

	/* As a fallback, use the system charging flag. */
	ret = apple_smc_read_flag(power->smc, SMC_KEY(CHSC));
	if (ret < 0)
		return ret;
	if (!ret)
		return POWER_SUPPLY_STATUS_NOT_CHARGING;
	else
		return POWER_SUPPLY_STATUS_CHARGING;
}

static int macsmc_battery_get_charge_behaviour(struct macsmc_power *power)
{
	int ret;
	u8 val;

	/* CH0I returns a bitmask like the low byte of CH0R */
	ret = apple_smc_read_u8(power->smc, SMC_KEY(CH0I), &val);
	if (ret)
		return ret;
	if (val & CH0R_NOAC_CH0I)
		return POWER_SUPPLY_CHARGE_BEHAVIOUR_FORCE_DISCHARGE;

	/* CH0C returns a bitmask containing CH0B/CH0C flags */
	ret = apple_smc_read_u8(power->smc, SMC_KEY(CH0C), &val);
	if (ret)
		return ret;
	if (val & CH0X_CH0C)
		return POWER_SUPPLY_CHARGE_BEHAVIOUR_INHIBIT_CHARGE;
	else
		return POWER_SUPPLY_CHARGE_BEHAVIOUR_AUTO;
}

static int macsmc_battery_set_charge_behaviour(struct macsmc_power *power, int val)
{
	u8 ch0i, ch0c;
	int ret;

	/*
	 * CH0I/CH0C are "hard" controls that will allow the battery to run down to 0.
	 * CH0K/CH0B are "soft" controls that are reset to 0 when SOC drops below 50%;
	 * we don't expose these yet.
	 */

	switch (val) {
	case POWER_SUPPLY_CHARGE_BEHAVIOUR_AUTO:
		ch0i = ch0c = 0;
		break;
	case POWER_SUPPLY_CHARGE_BEHAVIOUR_INHIBIT_CHARGE:
		ch0i = 0;
		ch0c = 1;
		break;
	case POWER_SUPPLY_CHARGE_BEHAVIOUR_FORCE_DISCHARGE:
		ch0i = 1;
		ch0c = 0;
		break;
	default:
		return -EINVAL;
	}

	ret = apple_smc_write_u8(power->smc, SMC_KEY(CH0I), ch0i);
	if (ret)
		return ret;
	return apple_smc_write_u8(power->smc, SMC_KEY(CH0C), ch0c);
}

static int macsmc_battery_get_date(const char *s, int *out)
{
	if (!isdigit(s[0]) || !isdigit(s[1]))
		return -ENOTSUPP;

	*out = (s[0] - '0') * 10 + s[1] - '0';
	return 0;
}

static int macsmc_battery_get_property(struct power_supply *psy,
				       enum power_supply_property psp,
				       union power_supply_propval *val)
{
	struct macsmc_power *power = power_supply_get_drvdata(psy);
	int ret = 0;
	u8 vu8;
	u16 vu16;
	u32 vu32;
	s16 vs16;
	s32 vs32;
	s64 vs64;

	switch (psp) {
	case POWER_SUPPLY_PROP_STATUS:
		val->intval = macsmc_battery_get_status(power);
		ret = val->intval < 0 ? val->intval : 0;
		break;
	case POWER_SUPPLY_PROP_PRESENT:
		val->intval = 1;
		break;
	case POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR:
		val->intval = macsmc_battery_get_charge_behaviour(power);
		ret = val->intval < 0 ? val->intval : 0;
		break;
	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW:
		ret = apple_smc_read_u16(power->smc, SMC_KEY(B0TE), &vu16);
		val->intval = vu16 == 0xffff ? 0 : vu16 * 60;
		break;
	case POWER_SUPPLY_PROP_TIME_TO_FULL_NOW:
		ret = apple_smc_read_u16(power->smc, SMC_KEY(B0TF), &vu16);
		val->intval = vu16 == 0xffff ? 0 : vu16 * 60;
		break;
	case POWER_SUPPLY_PROP_CAPACITY:
		ret = apple_smc_read_u8(power->smc, SMC_KEY(BUIC), &vu8);
		val->intval = vu8;
		break;
	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
		ret = apple_smc_read_u16(power->smc, SMC_KEY(B0AV), &vu16);
		val->intval = vu16 * 1000;
		break;
	case POWER_SUPPLY_PROP_CURRENT_NOW:
		ret = apple_smc_read_s16(power->smc, SMC_KEY(B0AC), &vs16);
		val->intval = vs16 * 1000;
		break;
	case POWER_SUPPLY_PROP_POWER_NOW:
		ret = apple_smc_read_s32(power->smc, SMC_KEY(B0AP), &vs32);
		val->intval = vs32 * 1000;
		break;
	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
		ret = apple_smc_read_u16(power->smc, SMC_KEY(BITV), &vu16);
		val->intval = vu16 * 1000;
		break;
	case POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT:
		ret = apple_smc_read_u16(power->smc, SMC_KEY(B0RC), &vu16);
		val->intval = vu16 * 1000;
		break;
	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
		ret = apple_smc_read_u32(power->smc, SMC_KEY(CSIL), &vu32);
		val->intval = vu32 * 1000;
		break;
	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
		ret = apple_smc_read_u16(power->smc, SMC_KEY(B0RI), &vu16);
		val->intval = vu16 * 1000;
		break;
	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
		ret = apple_smc_read_u16(power->smc, SMC_KEY(B0RV), &vu16);
		val->intval = vu16 * 1000;
		break;
	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
		ret = apple_smc_read_u16(power->smc, SMC_KEY(B0DC), &vu16);
		val->intval = vu16 * 1000;
		break;
	case POWER_SUPPLY_PROP_CHARGE_FULL:
		ret = apple_smc_read_u16(power->smc, SMC_KEY(B0FC), &vu16);
		val->intval = vu16 * 1000;
		break;
	case POWER_SUPPLY_PROP_CHARGE_NOW:
		ret = apple_smc_read_u16(power->smc, SMC_KEY(B0RM), &vu16);
		val->intval = swab16(vu16) * 1000;
		break;
	case POWER_SUPPLY_PROP_TEMP:
		ret = apple_smc_read_u16(power->smc, SMC_KEY(B0AT), &vu16);
		val->intval = vu16 - 2732;
		break;
	case POWER_SUPPLY_PROP_CHARGE_COUNTER:
		ret = apple_smc_read_s64(power->smc, SMC_KEY(BAAC), &vs64);
		val->intval = vs64;
		break;
	case POWER_SUPPLY_PROP_CYCLE_COUNT:
		ret = apple_smc_read_u16(power->smc, SMC_KEY(B0CT), &vu16);
		val->intval = vu16;
		break;
	case POWER_SUPPLY_PROP_SCOPE:
		val->intval = POWER_SUPPLY_SCOPE_SYSTEM;
		break;
	case POWER_SUPPLY_PROP_HEALTH:
		ret = apple_smc_read_flag(power->smc, SMC_KEY(BBAD));
		val->intval = ret == 1 ? POWER_SUPPLY_HEALTH_DEAD : POWER_SUPPLY_HEALTH_GOOD;
		ret = ret < 0 ? ret : 0;
		break;
	case POWER_SUPPLY_PROP_MODEL_NAME:
		val->strval = power->model_name;
		break;
	case POWER_SUPPLY_PROP_SERIAL_NUMBER:
		val->strval = power->serial_number;
		break;
	case POWER_SUPPLY_PROP_MANUFACTURE_YEAR:
		ret = macsmc_battery_get_date(&power->mfg_date[0], &val->intval);
		val->intval += 2000 - 8; /* -8 is a fixup for a firmware bug... */
		break;
	case POWER_SUPPLY_PROP_MANUFACTURE_MONTH:
		ret = macsmc_battery_get_date(&power->mfg_date[2], &val->intval);
		break;
	case POWER_SUPPLY_PROP_MANUFACTURE_DAY:
		ret = macsmc_battery_get_date(&power->mfg_date[4], &val->intval);
		break;
	default:
		return -EINVAL;
	}

	return ret;
}

static int macsmc_battery_set_property(struct power_supply *psy,
				       enum power_supply_property psp,
				       const union power_supply_propval *val)
{
	struct macsmc_power *power = power_supply_get_drvdata(psy);

	switch (psp) {
	case POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR:
		return macsmc_battery_set_charge_behaviour(power, val->intval);
	default:
		return -EINVAL;
	}
}

static int macsmc_battery_property_is_writeable(struct power_supply *psy,
						enum power_supply_property psp)
{
	switch (psp) {
	case POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR:
		return true;
	default:
		return false;
	}
}

static enum power_supply_property macsmc_battery_props[] = {
	POWER_SUPPLY_PROP_STATUS,
	POWER_SUPPLY_PROP_PRESENT,
	POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR,
	POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
	POWER_SUPPLY_PROP_TIME_TO_FULL_NOW,
	POWER_SUPPLY_PROP_CAPACITY,
	POWER_SUPPLY_PROP_VOLTAGE_NOW,
	POWER_SUPPLY_PROP_CURRENT_NOW,
	POWER_SUPPLY_PROP_POWER_NOW,
	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
	POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT,
	POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT,
	POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX,
	POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
	POWER_SUPPLY_PROP_CHARGE_FULL,
	POWER_SUPPLY_PROP_CHARGE_NOW,
	POWER_SUPPLY_PROP_TEMP,
	POWER_SUPPLY_PROP_CHARGE_COUNTER,
	POWER_SUPPLY_PROP_CYCLE_COUNT,
	POWER_SUPPLY_PROP_SCOPE,
	POWER_SUPPLY_PROP_HEALTH,
	POWER_SUPPLY_PROP_MODEL_NAME,
	POWER_SUPPLY_PROP_SERIAL_NUMBER,
	POWER_SUPPLY_PROP_MANUFACTURE_YEAR,
	POWER_SUPPLY_PROP_MANUFACTURE_MONTH,
	POWER_SUPPLY_PROP_MANUFACTURE_DAY,
};

static const struct power_supply_desc macsmc_battery_desc = {
	.name			= "macsmc-battery",
	.type			= POWER_SUPPLY_TYPE_BATTERY,
	.get_property		= macsmc_battery_get_property,
	.set_property		= macsmc_battery_set_property,
	.property_is_writeable	= macsmc_battery_property_is_writeable,
	.properties		= macsmc_battery_props,
	.num_properties		= ARRAY_SIZE(macsmc_battery_props),
};

static int macsmc_ac_get_property(struct power_supply *psy,
				       enum power_supply_property psp,
				       union power_supply_propval *val)
{
	struct macsmc_power *power = power_supply_get_drvdata(psy);
	int ret = 0;
	u16 vu16;
	u32 vu32;

	switch (psp) {
	case POWER_SUPPLY_PROP_ONLINE:
		ret = apple_smc_read_u32(power->smc, SMC_KEY(CHIS), &vu32);
		val->intval = !!vu32;
		break;
	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
		ret = apple_smc_read_u16(power->smc, SMC_KEY(AC-n), &vu16);
		val->intval = vu16 * 1000;
		break;
	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
		ret = apple_smc_read_u16(power->smc, SMC_KEY(AC-i), &vu16);
		val->intval = vu16 * 1000;
		break;
	case POWER_SUPPLY_PROP_INPUT_POWER_LIMIT:
		ret = apple_smc_read_u32(power->smc, SMC_KEY(ACPW), &vu32);
		val->intval = vu32 * 1000;
		break;
	default:
		return -EINVAL;
	}

	return ret;
}

static enum power_supply_property macsmc_ac_props[] = {
	POWER_SUPPLY_PROP_ONLINE,
	POWER_SUPPLY_PROP_VOLTAGE_NOW,
	POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT,
	POWER_SUPPLY_PROP_INPUT_POWER_LIMIT,
};

static const struct power_supply_desc macsmc_ac_desc = {
	.name			= "macsmc-ac",
	.type			= POWER_SUPPLY_TYPE_MAINS,
	.get_property		= macsmc_ac_get_property,
	.properties		= macsmc_ac_props,
	.num_properties		= ARRAY_SIZE(macsmc_ac_props),
};

static int macsmc_power_event(struct notifier_block *nb, unsigned long event, void *data)
{
	struct macsmc_power *power = container_of(nb, struct macsmc_power, nb);

	if ((event & 0xffffff00) == 0x71010100) {
		bool charging = (event & 0xff) != 0;

		dev_info(power->dev, "Charging: %d\n", charging);
		power_supply_changed(power->batt);
		power_supply_changed(power->ac);

		return NOTIFY_OK;
	}

	return NOTIFY_DONE;
}

static int macsmc_power_probe(struct platform_device *pdev)
{
	struct apple_smc *smc = dev_get_drvdata(pdev->dev.parent);
	struct power_supply_config psy_cfg = {};
	struct macsmc_power *power;
	int ret;

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

	power->dev = &pdev->dev;
	power->smc = smc;
	dev_set_drvdata(&pdev->dev, power);

	/* Ignore devices without a charger/battery */
	if (macsmc_battery_get_status(power) <= POWER_SUPPLY_STATUS_UNKNOWN)
		return -ENODEV;

	/* Fetch string properties */
	apple_smc_read(smc, SMC_KEY(BMDN), power->model_name, sizeof(power->model_name) - 1);
	apple_smc_read(smc, SMC_KEY(BMSN), power->serial_number, sizeof(power->serial_number) - 1);
	apple_smc_read(smc, SMC_KEY(BMDT), power->mfg_date, sizeof(power->mfg_date) - 1);

	/* Turn off the "optimized battery charging" flags, in case macOS left them on */
	apple_smc_write_u8(power->smc, SMC_KEY(CH0K), 0);
	apple_smc_write_u8(power->smc, SMC_KEY(CH0B), 0);

	psy_cfg.drv_data = power;
	power->batt = devm_power_supply_register(&pdev->dev, &macsmc_battery_desc, &psy_cfg);
	if (IS_ERR(power->batt)) {
		dev_err(&pdev->dev, "Failed to register battery\n");
		ret = PTR_ERR(power->batt);
		return ret;
	}

	power->ac = devm_power_supply_register(&pdev->dev, &macsmc_ac_desc, &psy_cfg);
	if (IS_ERR(power->ac)) {
		dev_err(&pdev->dev, "Failed to register AC adapter\n");
		ret = PTR_ERR(power->ac);
		return ret;
	}

	power->nb.notifier_call = macsmc_power_event;
	apple_smc_register_notifier(power->smc, &power->nb);

	return 0;
}

static int macsmc_power_remove(struct platform_device *pdev)
{
	struct macsmc_power *power = dev_get_drvdata(&pdev->dev);

	apple_smc_unregister_notifier(power->smc, &power->nb);

	return 0;
}

static struct platform_driver macsmc_power_driver = {
	.driver = {
		.name = "macsmc-power",
		.owner = THIS_MODULE,
	},
	.probe = macsmc_power_probe,
	.remove = macsmc_power_remove,
};
module_platform_driver(macsmc_power_driver);

MODULE_LICENSE("Dual MIT/GPL");
MODULE_DESCRIPTION("Apple SMC battery and power management driver");
MODULE_AUTHOR("Hector Martin <marcan@marcan.st>");
MODULE_ALIAS("platform:macsmc-power");