Overview of chargerd

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Charging management is mainly used for monitoring and managing the battery charging process, ensuring safe and fast charging of the battery. Currently, many IoT products come with batteries, and the charging circuits and chips have a certain degree of reusability. Therefore, implementing a universal charging management framework that integrates the characteristics of different charging circuits and chips enhances software reusability and maintainability.

Configuration Application of chargerd

The chargerd application in NuttX requires the following configuration.

Configuration for chargerd

To enable the chargerd service, the following configurations need to be set:

# Enable the chargerd service
CONFIG_CHARGERD=y

# If battery data from the fuel gauge requires b16 conversion, enable this configuration
CONFIG_CHARGERD_HWINTF_CONVERSION=y

# Default path for the chargerd configuration file, fill in the correct value if changed
CONFIG_CHARGERD_CONFIGURATION_FILE_PATH=/etc/chargerd_parameters.json

Starting chargerd

Add the startup process for the chargerd service in the startup script rcS as follows:

#ifdef CONFIG_CHARGERD
chargerd &
#endif

Packaging chargerd

Include the configuration file for chargerd in the ROMFS packaging script:

ifeq ($(CONFIG_CHARGERD),y)
RCRAWS += etc/charger_parameters.json
endif

Configuration File for chargerd

The chargerd configuration file is in JSON format. When chargerd starts, it reads the configuration file and initializes the chargerd service according to the configuration.

Parameters in Configuration File

Parameter Name	Parameter Format	Description
charger_supply	Parameter Value	Adjusts the power supply voltage device node for the charger chip
charger_adapter	Parameter Value	Device node for detecting charger plug/unplug events and charging types
charger	Parameter Value	Device node for the charging chip, multiple chips separated by ‘;’
fuel_gauge	Parameter Value	Device node for the battery fuel gauge
algo	Parameter Value	Charging algorithm used by the charging chip, multiple chips separated by ‘;’
polling_interval_ms	Parameter Value	Self-check timer polling interval
fullbatt_capacity	Parameter Value	Full charge condition (%)
fullbatt_current	Parameter Value	Full charge current condition (mA)
fullbatt_duration_ms	Parameter Value	Recovery time after full charge cutoff (ms)
fault_duration_ms	Parameter Value	Recovery time after fault protection (ms)
temp_min	Parameter Value	Low temperature protection threshold (0.1 Celsius)
temp_min_r	Parameter Value	Low temperature protection recovery threshold (0.1 Celsius)
temp_max	Parameter Value	High temperature protection threshold (0.1 Celsius)
temp_max_r	Parameter Value	High temperature protection recovery threshold (0.1 Celsius)
temp_skin	Parameter Value	Thermal shell temperature overheat threshold (0.1 Celsius)
temp_skin_r	Parameter Value	Thermal shell temperature overheat recovery threshold (0.1 Celsius)
enable_delay_ms	Parameter Value	Delay time (ms) for normal access after adapter is enabled
temp_rise_hys	Parameter Value	Temperature rise hysteresis value (0.1 Celsius)
temp_fall_hys	Parameter Value	Temperature fall hysteresis value (0.1 Celsius)
vol_rise_hys	Parameter Value	Voltage rise hysteresis value (mV)
vol_fall_hys	Parameter Value	Voltage fall hysteresis value (mV)
battery_default_param	Default battery parameters, see template	Information configured as battery when unable to obtain battery info via ioctl
charger_fault_plot_table	Charging error values, see template	Used when charging errors occur; parameters represent: {temperature range start (0.1 Celsius), temperature range end (0.1 Celsius), voltage range start (mV), voltage range end (mV), charger index (0 start, -1 indicates no charging), charging current (mA), charging voltage (mV)}
Charging Curve Table	Charging curve table, see template	1. name: name of the charging curve table; 2. mask: value obtained from left shift operation based on 1, e.g., 1 << 3, then mask is 8, indicating charging protocol corresponding to kernel data structure battery_protocol_e; 3. element_num: number of elements in the charging curve table; 4. your_plot_name_xxx: custom name for the charging curve table, must match the name parameter filled after the above name; 5. Curve table elements: placed after brackets, e.g., [-500,0,0,65535,-1,0,0], if there are multiple elements, write them in similar lines.
temperature_termination_voltage_table	Voltage table adjusted dynamically according to temperature	Cut-off voltage values adjusted dynamically based on temperature: 1. temp_vterm_enable: whether to enable this function; 2. temp_rise_hys: temperature rise hysteresis value; 3. temp_fall_hys: temperature fall hysteresis value; 4. relation_table: relationship between temperature range and cut-off voltage, e.g., [-100,0,3000], indicates that when the temperature is in the range of -10℃ ~ 0℃, the cut-off voltage is set to 3000mV.

Example of the chargerd Configuration File

Example configuration for chargerd:

{
    "charger_supply" : "/dev/charge/wireless_rx",
    "charger_adapter" : "/dev/charge/wireless_rx",
    "charger" : "/dev/charge/batt_charger;/dev/charge/charger_pump",
    "fuel_gauge" : "/dev/charge/batt_gauge",
    "algo" : "buck;pump",

    "polling_interval_ms" : 1000,
    "fullbatt_capacity" : 100,
    "fullbatt_current" : 0,
    "fullbatt_duration_ms" : 180000,
    "fault_duration_ms" : 60000,
    "temp_min" : 10,
    "temp_min_r" : 20,
    "temp_max" : 450,
    "temp_max_r" : 440,
    "temp_skin" : 400,
    "temp_skin_r" : 390,
    "temp_rise_hys" : 10,
    "temp_fall_hys" : 10,
    "vol_rise_hys" : 10,
    "vol_fall_hys" : 10,
    "enable_delay_ms" : 3000,
    "battery_default_param" : [
        {
            "capacity" : 0,
            "current" : 0,
            "temp" : 110,
            "vol" : 2100
        }
    ],

    "charger_fault_plot_table" : [
        {
            "temp_range_min" : 160,
            "temp_range_max" : 449,
            "vol_range_min" : 2100,
            "vol_range_max" : 65535,
            "charger_index" : 0,
            "work_current" : 145,
            "supply_vol" : 5500
        }
    ],

    "charger_plot_table_list" : [
        {
            "name" : "g_charger_plot_table",
            "mask" : 8,
            "element_num" : 15,
            "g_charger_plot_table" : [
                [-500,0,0,65535,-1,0,0],
                [1,119,2100,3000,0,20,5500],
                [1,119,3000,4435,0,145,5500],
                [1,119,4435,65535,0,145,5500],
                [120,159,2100,3000,0,20,5500],
                [120,159,3000,3600,0,145,5500],
                [120,159,3600,4140,0,486,5500],
                [120,159,4140,4435,0,340,5500],
                [120,159,4435,65535,0,340,5500],
                [160,449,2100,3000,0,20,5500],
                [160,449,3000,3650,0,145,5500],
                [160,449,3650,4140,1,920,0],
                [160,449,4140,4435,0,729,5500],
                [160,449,4435,65535,0,729,5500],
                [450,65535,0,65535,-1,0,0]
            ]
        },
        {
            "name" : "g_charger_plot_table_noStand_type3",
            "mask" : 4,
            "element_num" : 9,
            "g_charger_plot_table_noStand_type3" : [
                [-500,0,0,65535,-1,0,0],
                [1,159,2100,3000,0,20,5500],
                [1,159,3000,4435,0,145,5500],
                [1,159,4435,65535,0,145,5500],
                [160,449,2100,3000,0,20,5500],
                [160,449,3000,3600,0,145,5500],
                [160,449,3600,4435,0,486,5500],
                [160,449,4435,65535,0,486,5500],
                [450,65535,0,65535,-1,0,0]
            ]
        },
        {
            "name" : "g_charger_plot_table_noStand",
            "mask" : 3,
            "element_num" : 4,
            "g_charger_plot_table_noStand" : [
                [-500,0,0,65535,-1,0,0],
                [1,39,2100,65535,0,140,5500],
                [40,449,2100,65535,0,150,5500],
                [450,65535,0,65535,-1,0,0]
            ]
        }
    ]

    "temperature_termination_voltage_table" : [
        {
            "temp_vterm_enable" : 1,
            "temp_rise_hys" : 20,
            "temp_fall_hys" : 20,
            "relation_table" : [
                [-100,0,3000],
                [1,100,3000],
                [101,150,4000],
                [151,450,4400],
                [451,600,4000]
            ]
        }
    ]
}

Code Locations

The chargerd framework involves related code:

# Driver
Latest community code：nuttx/drivers/power/battery

# Healthd
frameworks/healthd/

# Chargerd
frameworks/charger

# uORB topic definition
frameworks/topics/include/system/state.h