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power: supply: macsmc_power: Driver for Apple SMC power/battery stats
This driver implements support for battery stats on top of the macsmc framework, to support Apple M1 Mac machines. Co-authored-by: Joey Gouly <[email protected]> Signed-off-by: Hector Martin <[email protected]>
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‎drivers/power/supply/Kconfig‎

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@@ -934,4 +934,11 @@ config BATTERY_UG3105
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device is off or suspended, the functionality of this driver is
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limited to reporting capacity only.
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config CHARGER_MACSMC
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tristate "Apple SMC Charger / Battery support"
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depends on APPLE_SMC
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help
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Say Y here to enable support for the charger and battery controls on
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Apple SMC controllers, as used on Apple Silicon Macs.
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endif # POWER_SUPPLY

‎drivers/power/supply/Makefile‎

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@@ -109,3 +109,4 @@ obj-$(CONFIG_BATTERY_ACER_A500) += acer_a500_battery.o
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obj-$(CONFIG_BATTERY_SURFACE) += surface_battery.o
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obj-$(CONFIG_CHARGER_SURFACE) += surface_charger.o
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obj-$(CONFIG_BATTERY_UG3105) += ug3105_battery.o
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obj-$(CONFIG_CHARGER_MACSMC) += macsmc_power.o

‎drivers/power/supply/macsmc_power.c‎

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// SPDX-License-Identifier: GPL-2.0-only OR MIT
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/*
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* Apple SMC Power/Battery Management
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* Copyright The Asahi Linux Contributors
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*/
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/mfd/core.h>
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#include <linux/mfd/macsmc.h>
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#include <linux/power_supply.h>
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#define MAX_STRING_LENGTH 256
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struct macsmc_power {
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struct device *dev;
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struct apple_smc *smc;
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struct power_supply *psy;
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char model_name[MAX_STRING_LENGTH];
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char serial_number[MAX_STRING_LENGTH];
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struct notifier_block nb;
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};
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static int macsmc_battery_get_status(struct macsmc_power *power)
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{
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u8 val;
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int ret;
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ret = apple_smc_read_u8(power->smc, SMC_KEY(BSFC), &val);
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if (ret)
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return ret;
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if (val == 1)
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return POWER_SUPPLY_STATUS_FULL;
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ret = apple_smc_read_u8(power->smc, SMC_KEY(CHSC), &val);
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if (ret)
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return ret;
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if (val == 1)
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return POWER_SUPPLY_STATUS_CHARGING;
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ret = apple_smc_read_u8(power->smc, SMC_KEY(CHCC), &val);
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if (ret)
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return ret;
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if (val == 0)
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return POWER_SUPPLY_STATUS_DISCHARGING;
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ret = apple_smc_read_u8(power->smc, SMC_KEY(CHCE), &val);
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if (ret)
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return ret;
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if (val == 0)
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return POWER_SUPPLY_STATUS_DISCHARGING;
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else
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return POWER_SUPPLY_STATUS_NOT_CHARGING;
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}
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static int macsmc_battery_get_property(struct power_supply *psy,
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enum power_supply_property psp,
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union power_supply_propval *val)
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{
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struct macsmc_power *power = power_supply_get_drvdata(psy);
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int ret = 0;
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u16 vu16;
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u32 vu32;
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s16 vs16;
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s32 vs32;
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s64 vs64;
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switch (psp) {
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case POWER_SUPPLY_PROP_STATUS:
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val->intval = macsmc_battery_get_status(power);
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ret = val->intval < 0 ? val->intval : 0;
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break;
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case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW:
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ret = apple_smc_read_u16(power->smc, SMC_KEY(B0TE), &vu16);
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val->intval = vu16 == 0xffff ? 0 : vu16 * 60;
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break;
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case POWER_SUPPLY_PROP_TIME_TO_FULL_NOW:
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ret = apple_smc_read_u16(power->smc, SMC_KEY(B0TF), &vu16);
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val->intval = vu16 == 0xffff ? 0 : vu16 * 60;
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break;
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case POWER_SUPPLY_PROP_CAPACITY:
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ret = apple_smc_read_u16(power->smc, SMC_KEY(BRSC), &vu16);
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val->intval = vu16;
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break;
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case POWER_SUPPLY_PROP_VOLTAGE_NOW:
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ret = apple_smc_read_u16(power->smc, SMC_KEY(B0AV), &vu16);
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val->intval = vu16 * 1000;
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break;
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case POWER_SUPPLY_PROP_CURRENT_NOW:
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ret = apple_smc_read_s16(power->smc, SMC_KEY(B0AC), &vs16);
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val->intval = vs16 * 1000;
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break;
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case POWER_SUPPLY_PROP_POWER_NOW:
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ret = apple_smc_read_s32(power->smc, SMC_KEY(B0AP), &vs32);
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val->intval = vs32 * 1000;
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break;
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case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
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ret = apple_smc_read_u16(power->smc, SMC_KEY(BITV), &vu16);
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val->intval = vu16 * 1000;
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break;
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case POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT:
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ret = apple_smc_read_u16(power->smc, SMC_KEY(B0RC), &vu16);
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val->intval = vu16 * 1000;
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break;
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case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
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ret = apple_smc_read_u32(power->smc, SMC_KEY(CSIL), &vu32);
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val->intval = vu32 * 1000;
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break;
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case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
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ret = apple_smc_read_u16(power->smc, SMC_KEY(B0RI), &vu16);
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val->intval = vu16 * 1000;
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break;
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case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
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ret = apple_smc_read_u16(power->smc, SMC_KEY(B0RV), &vu16);
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val->intval = vu16 * 1000;
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break;
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case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
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ret = apple_smc_read_u16(power->smc, SMC_KEY(B0DC), &vu16);
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val->intval = vu16 * 1000;
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break;
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case POWER_SUPPLY_PROP_CHARGE_FULL:
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ret = apple_smc_read_u16(power->smc, SMC_KEY(B0FC), &vu16);
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val->intval = vu16 * 1000;
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break;
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case POWER_SUPPLY_PROP_CHARGE_NOW:
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ret = apple_smc_read_u16(power->smc, SMC_KEY(B0RM), &vu16);
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val->intval = swab16(vu16) * 1000;
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break;
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case POWER_SUPPLY_PROP_TEMP:
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ret = apple_smc_read_u16(power->smc, SMC_KEY(B0AT), &vu16);
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val->intval = vu16 - 2732;
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break;
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case POWER_SUPPLY_PROP_CHARGE_COUNTER:
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ret = apple_smc_read_s64(power->smc, SMC_KEY(BAAC), &vs64);
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val->intval = vs64;
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break;
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case POWER_SUPPLY_PROP_MODEL_NAME:
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val->strval = power->model_name;
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break;
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case POWER_SUPPLY_PROP_SERIAL_NUMBER:
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val->strval = power->serial_number;
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break;
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default:
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return -EINVAL;
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}
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return ret;
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}
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static enum power_supply_property macsmc_battery_props[] = {
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POWER_SUPPLY_PROP_STATUS,
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POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
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POWER_SUPPLY_PROP_TIME_TO_FULL_NOW,
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POWER_SUPPLY_PROP_CAPACITY,
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POWER_SUPPLY_PROP_VOLTAGE_NOW,
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POWER_SUPPLY_PROP_CURRENT_NOW,
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POWER_SUPPLY_PROP_POWER_NOW,
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POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
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POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT,
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POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT,
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POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX,
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POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
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POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
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POWER_SUPPLY_PROP_CHARGE_FULL,
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POWER_SUPPLY_PROP_CHARGE_NOW,
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POWER_SUPPLY_PROP_TEMP,
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POWER_SUPPLY_PROP_CHARGE_COUNTER,
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POWER_SUPPLY_PROP_MODEL_NAME,
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POWER_SUPPLY_PROP_SERIAL_NUMBER,
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};
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static const struct power_supply_desc macsmc_battery_desc = {
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.name = "macsmc-battery",
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.type = POWER_SUPPLY_TYPE_BATTERY,
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.get_property = macsmc_battery_get_property,
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.properties = macsmc_battery_props,
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.num_properties = ARRAY_SIZE(macsmc_battery_props),
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};
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static int macsmc_power_event(struct notifier_block *nb, unsigned long event, void *data)
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{
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struct macsmc_power *power = container_of(nb, struct macsmc_power, nb);
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if ((event & 0xffffff00) == 0x71010100) {
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bool charging = (event & 0xff) != 0;
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dev_info(power->dev, "Charging: %d\n", charging);
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power_supply_changed(power->psy);
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return NOTIFY_OK;
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}
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return NOTIFY_DONE;
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}
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static int macsmc_power_probe(struct platform_device *pdev)
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{
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struct apple_smc *smc = dev_get_drvdata(pdev->dev.parent);
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struct power_supply_config psy_cfg = {};
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struct macsmc_power *power;
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int ret;
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power = devm_kzalloc(&pdev->dev, sizeof(*power), GFP_KERNEL);
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if (!power)
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return -ENOMEM;
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power->dev = &pdev->dev;
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power->smc = smc;
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dev_set_drvdata(&pdev->dev, power);
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/* Ignore devices without a charger/battery */
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if (macsmc_battery_get_status(power) <= POWER_SUPPLY_STATUS_UNKNOWN)
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return -ENODEV;
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/* Fetch string properties */
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apple_smc_read(smc, SMC_KEY(BMDN), power->model_name, sizeof(power->model_name) - 1);
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apple_smc_read(smc, SMC_KEY(BMSN), power->serial_number, sizeof(power->serial_number) - 1);
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psy_cfg.drv_data = power;
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power->psy = devm_power_supply_register(&pdev->dev, &macsmc_battery_desc, &psy_cfg);
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if (IS_ERR(power->psy)) {
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dev_err(&pdev->dev, "Failed to register power supply\n");
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ret = PTR_ERR(power->psy);
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return ret;
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}
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power->nb.notifier_call = macsmc_power_event;
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apple_smc_register_notifier(power->smc, &power->nb);
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return 0;
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}
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static int macsmc_power_remove(struct platform_device *pdev)
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{
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struct macsmc_power *power = dev_get_drvdata(&pdev->dev);
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apple_smc_unregister_notifier(power->smc, &power->nb);
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return 0;
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}
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static struct platform_driver macsmc_power_driver = {
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.driver = {
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.name = "macsmc-power",
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.owner = THIS_MODULE,
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},
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.probe = macsmc_power_probe,
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.remove = macsmc_power_remove,
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};
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module_platform_driver(macsmc_power_driver);
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MODULE_LICENSE("Dual MIT/GPL");
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MODULE_DESCRIPTION("Apple SMC battery and power management driver");
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MODULE_AUTHOR("Hector Martin <[email protected]>");
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MODULE_ALIAS("platform:macsmc-power");

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