高通电源管理qpnp-vm-bms驱动

1. compatible节点：

qpnp-vm-bms.c使用来控制电池曲线的和BMS功能的，其compatible节点是"qcom,qpnp-vm-bms"

2. probe函数：

qpnp_vm_bms_probe函数如下：

static int qpnp_vm_bms_probe(struct spmi_device *spmi)
{
    struct qpnp_bms_chip *chip;
    struct device_node *revid_dev_node;
    int rc, vbatt = 0;

    chip = devm_kzalloc(&spmi->dev, sizeof(*chip), GFP_KERNEL);
    if (!chip) {
        pr_err("kzalloc() failed.\n");
        return -ENOMEM;
    }

    //获取ADC的值，ADC是电流的大小，绑定vadc，并且获取温度，设备列表
    rc = bms_get_adc(chip, spmi);
    if (rc < 0) {
        pr_err("Failed to get adc rc=%d\n", rc);
        return rc;
    }

    //指向revision外围节点的phandle，vm-bus需要配置这个节点
    revid_dev_node = of_parse_phandle(spmi->dev.of_node,
                        "qcom,pmic-revid", 0);
    if (!revid_dev_node) {
        pr_err("Missing qcom,pmic-revid property\n");
        return -EINVAL;
    }
    
    //返回pmic的修订信息
    chip->revid_data = get_revid_data(revid_dev_node);
    if (IS_ERR(chip->revid_data)) {
        pr_err("revid error rc = %ld\n", PTR_ERR(chip->revid_data));
        return -EINVAL;
    }
    if ((chip->revid_data->pmic_subtype == PM8916_V2P0_SUBTYPE) &&
                chip->revid_data->rev4 == PM8916_V2P0_REV4)
        chip->workaround_flag |= WRKARND_PON_OCV_COMP;

    //查看是否是热启动的，热启动就是在不关闭设备的情况下，重启电脑
    rc = qpnp_pon_is_warm_reset();
    if (rc < 0) {
        pr_err("Error reading warm reset status rc=%d\n", rc);
        return rc;
    }
    chip->warm_reset = !!rc;

    //解析spmi设备的内容，并且在其中寻找它的中断基地址
    rc = parse_spmi_dt_properties(chip, spmi);
    if (rc) {
        pr_err("Error registering spmi resource rc=%d\n", rc);
        return rc;
    }

    //解析电池的参数，如v-cutoff-uv，关机电压，它不会读qcom的内容，会直接读qcom,后面的内容会有仔细说
    rc = parse_bms_dt_properties(chip);
    if (rc) {
        pr_err("Unable to read all bms properties, rc = %d\n", rc);
        return rc;
    }

    //查询错误的原因
    if (chip->dt.cfg_disable_bms) {
        pr_info("VMBMS disabled (disable-bms = 1)\n");
        rc = qpnp_masked_write_base(chip, chip->base + EN_CTL_REG,
                            BMS_EN_BIT, 0);
        if (rc)
            pr_err("Unable to disable VMBMS rc=%d\n", rc);
        return -ENODEV;
    }

    //读取存在pm？PM里读出来的未经修正的原始数据？
    rc = qpnp_read_wrapper(chip, chip->revision,
                chip->base + REVISION1_REG, 2);
    if (rc) {
        pr_err("Error reading version register rc=%d\n", rc);
        return rc;
    }

    pr_debug("BMS version: %hhu.%hhu\n",
            chip->revision[1], chip->revision[0]);

    dev_set_drvdata(&spmi->dev, chip);
    device_init_wakeup(&spmi->dev, 1);
    mutex_init(&chip->bms_data_mutex);
    mutex_init(&chip->bms_device_mutex);
    mutex_init(&chip->last_soc_mutex);
    mutex_init(&chip->state_change_mutex);
    init_waitqueue_head(&chip->bms_wait_q);     //初始化队列

    /* read battery-id and select the battery profile */
    //设置电池数据，也就是电池曲线
    rc = set_battery_data(chip);
    if (rc) {
        pr_err("Unable to read battery data %d\n", rc);
        goto fail_init;
    }

    /* set the battery profile */
    //设置电池的配置文件，其实也就是配置刚刚设置好的全局变量了
    rc = config_battery_data(chip->batt_data);
    if (rc) {
        pr_err("Unable to config battery data %d\n", rc);
        goto fail_init;
    }

    //初始化wakeup_source，内核睡眠机制
    wakeup_source_init(&chip->vbms_lv_wake_source.source, "vbms_lv_wake");
    wakeup_source_init(&chip->vbms_cv_wake_source.source, "vbms_cv_wake");
    wakeup_source_init(&chip->vbms_soc_wake_source.source, "vbms_soc_wake");
    //初始化工作队列
    INIT_DELAYED_WORK(&chip->monitor_soc_work, monitor_soc_work);
    INIT_DELAYED_WORK(&chip->voltage_soc_timeout_work,
                    voltage_soc_timeout_work);
    //初始化配置状态，各种状态
    bms_init_defaults(chip);
    //这一句看不懂了，可能是电池BMS算法用来读取硬件配置的
    bms_load_hw_defaults(chip);
    
    //通过判断power_supply里面的函数来确定是否是正在充电的状态
    is_bat_pres_ght =(is_battery_present(chip)); 

    pr_err("is_bat_pres_ght =%d\n",is_bat_pres_ght);
    ///if (is_battery_present(chip)) {
    //如果电池正在充电
    if (is_bat_pres_ght) {
        //设置电池的设置低电(高电，高温，低温)的阈值，也就是电池低电关机
        rc = setup_vbat_monitoring(chip);
        if (rc) {
            pr_err("fail to configure vbat monitoring rc=%d\n",
                    rc);
            goto fail_setup;
        }
    }
    
    //请求一些相应的中断BMS
    rc = bms_request_irqs(chip);
    if (rc) {
        pr_err("error requesting bms irqs, rc = %d\n", rc);
        goto fail_irq;
    }

    //电池一些常规的检测，主要从PMIC上读到的相关信息  
    //电池的插入状态检测，判断手段是如果当前状态和之前状态不一样就判断电池拔出，并且确定电池是否存在，否则重置
    battery_insertion_check(chip);
    //电池状态检测
    battery_status_check(chip);

    /* character device to pass data to the userspace */
    //向上层注册字符设备
    rc = register_bms_char_device(chip);
    if (rc) {
        pr_err("Unable to regiter '/dev/vm_bms' rc=%d\n", rc);
        goto fail_bms_device;
    }

    the_chip = chip;
    //这个也很重要，我们从上节知道，初值last_ocv_soc是非常重要的，决定着后面的soc估值算法，计算估值电压
    calculate_initial_soc(chip);
    if (chip->dt.cfg_battery_aging_comp) {
        rc = calculate_initial_aging_comp(chip);
        if (rc)
            pr_err("Unable to calculate initial aging data rc=%d\n",
                    rc);
    }

    //设置和注册电池的power supply
    /* setup & register the battery power supply */
    chip->bms_psy.name = "bms";
    chip->bms_psy.type = POWER_SUPPLY_TYPE_BMS;
    chip->bms_psy.properties = bms_power_props;
    chip->bms_psy.num_properties = ARRAY_SIZE(bms_power_props);
    chip->bms_psy.get_property = qpnp_vm_bms_power_get_property;
    chip->bms_psy.set_property = qpnp_vm_bms_power_set_property;
    chip->bms_psy.external_power_changed = qpnp_vm_bms_ext_power_changed;
    chip->bms_psy.property_is_writeable = qpnp_vm_bms_property_is_writeable;
    chip->bms_psy.supplied_to = qpnp_vm_bms_supplicants;
    chip->bms_psy.num_supplicants = ARRAY_SIZE(qpnp_vm_bms_supplicants);

    //power_supply注册
    rc = power_supply_register(chip->dev, &chip->bms_psy);
    if (rc < 0) {
        pr_err("power_supply_register bms failed rc = %d\n", rc);
        goto fail_psy;
    }
    chip->bms_psy_registered = true;

    rc = get_battery_voltage(chip, &vbatt);
    if (rc) {
        pr_err("error reading vbat_sns adc channel=%d, rc=%d\n",
                            VBAT_SNS, rc);
        goto fail_get_vtg;
    }

    chip->debug_root = debugfs_create_dir("qpnp_vmbms", NULL);
    if (!chip->debug_root)
        pr_err("Couldn't create debug dir\n");

    if (chip->debug_root) {
        struct dentry *ent;

        ent = debugfs_create_file("bms_data", S_IFREG | S_IRUGO,
                      chip->debug_root, chip,
                      &bms_data_debugfs_ops);
        if (!ent)
            pr_err("Couldn't create bms_data debug file\n");

        ent = debugfs_create_file("bms_config", S_IFREG | S_IRUGO,
                      chip->debug_root, chip,
                      &bms_config_debugfs_ops);
        if (!ent)
            pr_err("Couldn't create bms_config debug file\n");

        ent = debugfs_create_file("bms_status", S_IFREG | S_IRUGO,
                      chip->debug_root, chip,
                      &bms_status_debugfs_ops);
        if (!ent)
            pr_err("Couldn't create bms_status debug file\n");
    }
    
    
    //这里启动工作队列，绝大部分的工作内容都是在这里完成的
    schedule_delayed_work(&chip->monitor_soc_work, 0);

    /*
     * schedule a work to check if the userspace vmbms module
     * has registered. Fall-back to voltage-based-soc reporting
     * if it has not.
     */
     
     //
    schedule_delayed_work(&chip->voltage_soc_timeout_work,
        msecs_to_jiffies(chip->dt.cfg_voltage_soc_timeout_ms));

    pr_info("probe success: soc=%d vbatt=%d ocv=%d warm_reset=%d\n",
                    get_prop_bms_capacity(chip), vbatt,
                    chip->last_ocv_uv, chip->warm_reset);

    return rc;

fail_get_vtg:
    power_supply_unregister(&chip->bms_psy);
fail_psy:
    device_destroy(chip->bms_class, chip->dev_no);
    cdev_del(&chip->bms_cdev);
    unregister_chrdev_region(chip->dev_no, 1);
fail_bms_device:
    chip->bms_psy_registered = false;
fail_irq:
    reset_vbat_monitoring(chip);
fail_setup:
    wakeup_source_trash(&chip->vbms_lv_wake_source.source);
    wakeup_source_trash(&chip->vbms_cv_wake_source.source);
    wakeup_source_trash(&chip->vbms_soc_wake_source.source);
fail_init:
    mutex_destroy(&chip->bms_data_mutex);
    mutex_destroy(&chip->last_soc_mutex);
    mutex_destroy(&chip->state_change_mutex);
    mutex_destroy(&chip->bms_device_mutex);
    the_chip = NULL;

    return rc;
}

2.1 parse_bms_dt_properties()函数

在这里我们详细分析一下各个节点的内容，这里就挑几个比较重要的看看：（详细可以参考设备树里面的内容）

• v-cutoff-uv：如修改关机电压，除了修改这里，还需要修改电池曲线数据的qcom,v-cutoff-uv，其实最好是用电池曲线数据里的
• max-voltage-uv：电池最大的电压，单位为毫伏
• qcom,r-conn-mohm ：连接器的电阻
• s1-sample-interval-ms：状态s1下累加器的采样（毫秒）。（即）累加器充满vbat样本的速率。最小值=0最大值=2550ms。
• resume-soc：当充满的电池百分比低于此值，则重新开始充电。
• volatge-soc-timeout-ms：如果没有使用VMBMS算法来计算SOC，模块在此时间后基于SOC来报告电压。
• low-temp-threshold：当温度阈值低于此值，禁用IBAT求取平均值和UUC(不可用电量)平滑功能，如没指定默认为0，我们这里没有指定。
• qcom,ignore-shutdown-soc：有些不看翻译对大家都好；
• qcom,use-voltage-soc ：BMS根据此项的值来决定是否采用基于电压的SOC来替代基于库伦电量计的方式
• qcom,use-reported-soc ：此项使能reported_soc逻辑，而且要定义qcom,resume-soc为一个合适的值，BMS也需要控制充电、停止充电和重新充电。高通给出的代码默认是定义qcom,use-reported-soc，但我们核心板厂家注释掉此项，并增加qcom,report-charger-eoc
• qcom,report-charger-eoc： 指示BMS需要通知EOC(充电结束)给充电器
• qcom,disable-bms ：此属性用于关闭VM BMS硬件模块

2.2 set_battery_data()函数

这一部分内容就是设置电池曲线内容：

下面就是电池曲线的详细内容，不仔细说了：

static int set_battery_data(struct qpnp_bms_chip *chip)
{
    int64_t battery_id;
    int rc = 0;
    struct bms_battery_data *batt_data;
    struct device_node *node;
    
    //里面的内容通过读取ADC来获取ID号
    battery_id = read_battery_id(chip);
    if (battery_id < 0) {
        pr_err("cannot read battery id err = %lld\n", battery_id);
        return battery_id;
    }
    node = of_find_node_by_name(chip->spmi->dev.of_node,
                    "qcom,battery-data");
    if (!node) {
            pr_err("No available batterydata\n");
            return -EINVAL;
    }

    batt_data = devm_kzalloc(chip->dev,
            sizeof(struct bms_battery_data), GFP_KERNEL);
    if (!batt_data) {
        pr_err("Could not alloc battery data\n");
        return -EINVAL;
    }

    batt_data->fcc_temp_lut = devm_kzalloc(chip->dev,
        sizeof(struct single_row_lut), GFP_KERNEL);
    batt_data->pc_temp_ocv_lut = devm_kzalloc(chip->dev,
            sizeof(struct pc_temp_ocv_lut), GFP_KERNEL);
    batt_data->rbatt_sf_lut = devm_kzalloc(chip->dev,
                sizeof(struct sf_lut), GFP_KERNEL);
    batt_data->ibat_acc_lut = devm_kzalloc(chip->dev,
                sizeof(struct ibat_temp_acc_lut), GFP_KERNEL);

    batt_data->max_voltage_uv = -1;
    batt_data->cutoff_uv = -1;
    batt_data->iterm_ua = -1;

    /*
     * if the alloced luts are 0s, of_batterydata_read_data ignores
     * them.
     */
    rc = of_batterydata_read_data(node, batt_data, battery_id);
    if (rc || !batt_data->pc_temp_ocv_lut
        || !batt_data->fcc_temp_lut
        || !batt_data->rbatt_sf_lut
        || !batt_data->ibat_acc_lut) {
        pr_err("battery data load failed\n");
        devm_kfree(chip->dev, batt_data->fcc_temp_lut);
        devm_kfree(chip->dev, batt_data->pc_temp_ocv_lut);
        devm_kfree(chip->dev, batt_data->rbatt_sf_lut);
        devm_kfree(chip->dev, batt_data->ibat_acc_lut);
        devm_kfree(chip->dev, batt_data);
        return rc;
    }

    if (batt_data->pc_temp_ocv_lut == NULL) {
        pr_err("temp ocv lut table has not been loaded\n");
        devm_kfree(chip->dev, batt_data->fcc_temp_lut);
        devm_kfree(chip->dev, batt_data->pc_temp_ocv_lut);
        devm_kfree(chip->dev, batt_data->rbatt_sf_lut);
        devm_kfree(chip->dev, batt_data->ibat_acc_lut);
        devm_kfree(chip->dev, batt_data);

        return -EINVAL;
    }

    /* check if ibat_acc_lut is valid */
    if (!batt_data->ibat_acc_lut->rows) {
        pr_info("ibat_acc_lut not present\n");
        devm_kfree(chip->dev, batt_data->ibat_acc_lut);
        batt_data->ibat_acc_lut = NULL;
    }

    /* Override battery properties if specified in the battery profile */
    if (batt_data->max_voltage_uv >= 0)
        chip->dt.cfg_max_voltage_uv = batt_data->max_voltage_uv;
    if (batt_data->cutoff_uv >= 0)
        chip->dt.cfg_v_cutoff_uv = batt_data->cutoff_uv;

    chip->batt_data = batt_data;

    return 0;
}

在of_batterydata_read_data函数中有一个返回值：

of_batterydata_read_data->
of_batterydata_load_battery_data

of_batterydata_load_battery_data函数中有配置电池曲线的东西；

2.3 高通电量计

术语	全称	注释
FCC	Full-Charge Capacity	满电荷电量
UC	Remaining capacity	RC 剩余电量
CC	Coulumb counter	电量计
UUC	Unusable capacity	不可用电量
RUC	Remaining usable capacity //	RUC=RC-CC-UUC RUC=RC-CC-UUC，剩余可用电量
SoC	State of charge	电量百分比
OCV	Open circuit voltage	开路电压，电池在开路状态下的端电压称为开路电压

SOC=(RC-CC-UUC)/(FCC-UUC)

以下是各个变量的计算方法：

2.3.1 FCC：

在校准的电池profile中有定义,会随温度有变化；

static struct single_row_lut fcc_temp = {
 .x  = {-20, 0, 25, 40, 60},
 .y  = {3193, 3190, 3190, 3180, 3183},
 .cols = 5
}

对应电池曲线的qcom,fcc-temp-lut；

2.3.2 pc-temp-ocv-lut:

qcom,pc-temp-ocv-lut，为温度、SOC对应得电压表，PMU8909获取的电压值，通过查该表，在温度和电压下，可得到当前的SOC。

对应电池曲线的qcom,pc-temp-ocv-lut

2.3.3 rbatt-sf-lut:

rbatt-sf-lut，为温度、soc对应的电池内阻表，这里主要考虑内阻的影响，对OCV的修正，new_ocv=ocv+rbatt(内阻)*current（当前电流）。

对应电池曲线的qcom,rbatt-sf-lut

2.3.3 ibat-acc-luit

ibat-acc-luit，为温度、电流对应的acc表，这两个是起到修正SOC的作用

对应电池曲线的qcom, ibat-acc-luit

2.3.4 计算公式

soc_uuc = ((fcc - acc) * 100) / fcc，

//fcc在qcom,fcc-temp-lut查表可知、acc在qcom, ibat-acc-luit查表可知

soc_acc = DIV_ROUND_CLOSEST(100 * (soc_ocv - soc_uuc),(100 - soc_uuc));

//最终soc_acc，为上报的SOC.soc_ocv则是在qcom,pc-temp-ocv-lut查表可知

2.3.5 BMS算法

会上报事件uevent，当HAL层，收到消息，然后调用getprop的方法，获取相关的参数，如，电阻、电流、fcc、acc等，来估算出last_ocv_uv，然后调用setprop，把该值设下去，并启动工作线程，根据last_ocv_uv，查表得到soc，并经过修正SOC，并再次上报事件，循环下去。这个估值算法，我猜可能是一套学习算法，具体的没有源码，不清楚，只知道它把算法变为.bin文件，用了binder机制，作为服务一直运行。

我们如何知道monitor_soc_work函数不断的运行呢？

原因在于：

static void monitor_soc_work(struct work_struct *work) {
    ......
    if ((chip->last_soc != chip->calculated_soc) ||
                    chip->dt.cfg_use_voltage_soc)
    schedule_delayed_work(&chip->monitor_soc_work,
    msecs_to_jiffies(get_calculation_delay_ms(chip)));
}

2.3.6 分析如何确定初始的last_ocv_uv：

static int calculate_initial_soc(struct qpnp_bms_chip *chip)
{
    ........
    ........
    //读当前电池温度
    rc = get_batt_therm(chip, &batt_temp);
    ............
    //读PON OCV
    rc = read_and_update_ocv(chip, batt_temp, true);
    ..........
    //读关机保存的soc和last_soc_uv
    
    rc = read_shutdown_ocv_soc(chip);
 
    //这里判断是使用估计soc还是估值soc。如果chip->warm_reset 为真
    if (chip->warm_reset) {
        if (chip->shutdown_soc_invalid) { //这个是dtsi的一个配置选项，若没有配置，
                        //则不使用关机soc
            est_ocv = estimate_ocv(chip); //估值soc
            chip->last_ocv_uv = est_ocv;
        } else {
            chip->last_ocv_uv = chip->shutdown_ocv;//使用关机的soc和ocv
            pr_err("Hyan %d : set chip->last_ocv_uv = %d\n", __LINE__, chip->last_ocv_uv);
            chip->last_soc = chip->shutdown_soc;
            chip->calculated_soc = lookup_soc_ocv(chip,
                        chip->shutdown_ocv, batt_temp);
        }
    } else {
 
        if (chip->workaround_flag & WRKARND_PON_OCV_COMP)
            adjust_pon_ocv(chip, batt_temp);
 
         /* !warm_reset use PON OCV only if shutdown SOC is invalid */
        chip->calculated_soc = lookup_soc_ocv(chip,
                    chip->last_ocv_uv, batt_temp);
        if (!chip->shutdown_soc_invalid &&
            (abs(chip->shutdown_soc - chip->calculated_soc) <
                chip->dt.cfg_shutdown_soc_valid_limit)) {
            chip->last_ocv_uv = chip->shutdown_ocv; 
            chip->last_soc = chip->shutdown_soc;
            chip->calculated_soc = lookup_soc_ocv(chip,
                        chip->shutdown_ocv, batt_temp);//使用估值soc
            
        } else {
            chip->shutdown_soc_invalid = true; //使用关机soc
            
        }
    }
    .............
    ............
}
 
    //得到PON OCV
    rc = read_and_update_ocv(chip, batt_temp, true);
        ocv_uv = convert_vbatt_raw_to_uv(chip, ocv_data, is_pon_ocv);
                uv = vadc_reading_to_uv(reading, true); //读ADC值
                uv = adjust_vbatt_reading(chip, uv);   //转化为soc_uv
                rc = qpnp_vbat_sns_comp_result(chip->vadc_dev, &uv, is_pon_ocv); //根据IC的类型，进行温度补偿
    //从寄存器中读到储存的soc和ocv
    read_shutdown_ocv_soc
        rc = qpnp_read_wrapper(chip, (u8 *)&stored_ocv,
                chip->base + BMS_OCV_REG, 2);
        rc = qpnp_read_wrapper(chip, &stored_soc, chip->base + BMS_SOC_REG, 1);
 
    adjust_pon_ocv(struct qpnp_bms_chip *chip, int batt_temp)
        rc = qpnp_vadc_read(chip->vadc_dev, DIE_TEMP, &result); 
        pc = interpolate_pc(chip->batt_data->pc_temp_ocv_lut,
                    batt_temp, chip->last_ocv_uv / 1000); //根据ocv和temp，查表得PC(soc)。
        rbatt_mohm = get_rbatt(chip, pc, batt_temp); //根据soc和temp，得电池内阻值
        /* convert die_temp to DECIDEGC */
        die_temp = (int)result.physical / 100;     
        current_ma = interpolate_current_comp(die_temp);  //当前电流
        delta_uv = rbatt_mohm * current_ma;
        chip->last_ocv_uv += delta_uv;   //修正last_ocv_uv
 
    //这个函数主要根据last_ocv_uv，计算出soc的
    lookup_soc_ocv(struct qpnp_bms_chip *chip, int ocv_uv, int batt_temp)
            //查表得到soc_ocv，soc_cutoff
            soc_ocv = interpolate_pc(chip->batt_data->pc_temp_ocv_lut,
                    batt_temp, ocv_uv / 1000);
            soc_cutoff = interpolate_pc(chip->batt_data->pc_temp_ocv_lut,
                batt_temp, chip->dt.cfg_v_cutoff_uv / 1000);
 
            soc_final = DIV_ROUND_CLOSEST(100 * (soc_ocv - soc_cutoff),
                            (100 - soc_cutoff));
 
            if (batt_temp > chip->dt.cfg_low_temp_threshold)
                iavg_ma = calculate_uuc_iavg(chip);
            else
                iavg_ma = chip->current_now / 1000;
            //查表得到FCC，ACC
            fcc = interpolate_fcc(chip->batt_data->fcc_temp_lut,
                                batt_temp);
            acc = interpolate_acc(chip->batt_data->ibat_acc_lut,
                            batt_temp, iavg_ma);
            //计算出UUC
            soc_uuc = ((fcc - acc) * 100) / fcc;
 
            if (batt_temp > chip->dt.cfg_low_temp_threshold)
                soc_uuc = adjust_uuc(chip, soc_uuc);
            //得到soc_acc
            soc_acc = DIV_ROUND_CLOSEST(100 * (soc_ocv - soc_uuc),
                            (100 - soc_uuc));
 
            soc_final = soc_acc;   //这个为上报的soc
            chip->last_acc = acc;

在这里获取last_ocv_uv，温度；

2.3.7 工作队列monitor_soc_work

static void monitor_soc_work(struct work_struct *work)
{
    struct qpnp_bms_chip *chip = container_of(work,
                struct qpnp_bms_chip,
                monitor_soc_work.work);
    int rc, new_soc = 0, batt_temp;

    bms_stay_awake(&chip->vbms_soc_wake_source);
    
    //计算上次工作队列和这次工作队列的差值
    calculate_delta_time(&chip->tm_sec, &chip->delta_time_s);
    pr_debug("elapsed_time=%d\n", chip->delta_time_s);

    mutex_lock(&chip->last_soc_mutex);

    //电池不存在，报100%电量
    if (!is_battery_present(chip)) {
        /* if battery is not preset report 100% SOC */
        pr_debug("battery gone, reporting 100\n");
        chip->last_soc_invalid = true;
        chip->last_soc = -EINVAL;
        new_soc = 100;
    } else {
        //检测电池电压
        battery_voltage_check(chip);
        //假设这个qcom,use-voltage-soc节点打开，就使用电压来计算soc
        if (chip->dt.cfg_use_voltage_soc) {
            //通过电压计算soc
            calculate_soc_from_voltage(chip);
        } else {
            //获取电池的温度
            rc = get_batt_therm(chip, &batt_temp);
            if (rc < 0) {
                pr_err("Unable to read batt temp rc=%d, using default=%d\n",
                            rc, BMS_DEFAULT_TEMP);
                batt_temp = BMS_DEFAULT_TEMP;
            }

            if (chip->last_soc_invalid) {
                chip->last_soc_invalid = false;
                chip->last_soc = -EINVAL;
            }
            
            //这里使用last_ocv_uv算出soc的
            new_soc = lookup_soc_ocv(chip, chip->last_ocv_uv,
                                batt_temp);
            /* clamp soc due to BMS hw/sw immaturities */
            new_soc = clamp_soc_based_on_voltage(chip, new_soc);
            
            
            //上次的电压不等于这次的电压
            if (chip->calculated_soc != new_soc) {
                pr_debug("SOC changed! new_soc=%d prev_soc=%d\n",
                        new_soc, chip->calculated_soc);
                chip->calculated_soc = new_soc;
                /*
                 * To recalculate the catch-up time, clear it
                 * when SOC changes.
                 */
                chip->catch_up_time_sec = 0;

                if (chip->calculated_soc == 100)
                    /* update last_soc immediately */
                    report_vm_bms_soc(chip);

                pr_debug("update bms_psy\n");
                power_supply_changed(&chip->bms_psy);
            } else if (chip->last_soc != chip->calculated_soc) {
                pr_debug("update bms_psy\n");
                power_supply_changed(&chip->bms_psy);
            } else {
                report_vm_bms_soc(chip);
            }
        }
        /* low SOC configuration */
        low_soc_check(chip);
    }
    /*
     * schedule the work only if last_soc has not caught up with
     * the calculated soc or if we are using voltage based soc
     */
    if ((chip->last_soc != chip->calculated_soc) ||
                    chip->dt.cfg_use_voltage_soc)
        schedule_delayed_work(&chip->monitor_soc_work,
            msecs_to_jiffies(get_calculation_delay_ms(chip)));

    //复充标志位
    if (chip->reported_soc_in_use && chip->charger_removed_since_full
                && !chip->charger_reinserted) {
        /* record the elapsed time after last reported_soc change */
        chip->reported_soc_change_sec += chip->delta_time_s;
        pr_debug("reported_soc_change_sec=%d\n",
                    chip->reported_soc_change_sec);

        /* above the catch up time, calculate new reported_soc */
        if (chip->reported_soc_change_sec > UI_SOC_CATCHUP_TIME) {
            calculate_reported_soc(chip);
            chip->reported_soc_change_sec = 0;
        }
    }

    mutex_unlock(&chip->last_soc_mutex);

    bms_relax(&chip->vbms_soc_wake_source);
}

上面注释已经写的差不多了；看一下上报函数report_vm_bms_soc：

last_soc其实与calcaulte_soc差不多，但是last_soc也包括了上次开机前的soc

static int report_vm_bms_soc(struct qpnp_bms_chip *chip)
{
    int soc, soc_change, batt_temp, rc;
    int time_since_last_change_sec = 0, charge_time_sec = 0;
    unsigned long last_change_sec;
    bool charging;

    soc = chip->calculated_soc;

    last_change_sec = chip->last_soc_change_sec;
    //计算上次电量改变的情况
    calculate_delta_time(&last_change_sec, &time_since_last_change_sec);

    //判断电量是否正在充电
    charging = is_battery_charging(chip);

    pr_debug("charging=%d last_soc=%d last_soc_unbound=%d\n",
        charging, chip->last_soc, chip->last_soc_unbound);
    /*
     * account for charge time - limit it to SOC_CATCHUP_SEC to
     * avoid overflows when charging continues for extended periods
     */
     //正在充电,last_soc是指上一次的最开始开机的soc，与计算出来的soc不一样，这是第一次，last_soc之后就会改变了，这里是初始化时间
     //这段大概是BMS算法机制的东西，说明充电时间-将其限制在SOC_catchup_sec，以避免充电持续较长时间时溢出
    if (charging && chip->last_soc != -EINVAL) {
        if (chip->charge_start_tm_sec == 0 ||
            (chip->catch_up_time_sec == 0 &&
                (abs(soc - chip->last_soc) >= MIN_SOC_UUC))) {
            /*
             * calculating soc for the first time
             * after start of chg. Initialize catchup time
             */
            if (abs(soc - chip->last_soc) < MAX_CATCHUP_SOC)
                chip->catch_up_time_sec =
                (soc - chip->last_soc)
                    * SOC_CATCHUP_SEC_PER_PERCENT;
            else
                chip->catch_up_time_sec = SOC_CATCHUP_SEC_MAX;

            chip->chg_start_soc = chip->last_soc;

            if (chip->catch_up_time_sec < 0)
                chip->catch_up_time_sec = 0;
            chip->charge_start_tm_sec = last_change_sec;

            pr_debug("chg_start_soc=%d charge_start_tm_sec=%d catch_up_time_sec=%d\n",
                chip->chg_start_soc, chip->charge_start_tm_sec,
                        chip->catch_up_time_sec);
        }

        charge_time_sec = min(SOC_CATCHUP_SEC_MAX, (int)last_change_sec
                - chip->charge_start_tm_sec);

        /* end catchup if calculated soc and last soc are same */
        if (chip->last_soc == soc) {
            chip->catch_up_time_sec = 0;
            chip->chg_start_soc = chip->last_soc;
        }
    }

    //充电状态
    if (chip->last_soc != -EINVAL) {
        /*
         * last_soc < soc  ... if we have not been charging at all
         * since the last time this was called, report previous SoC.
         * Otherwise, scale and catch up.
         */
        rc = get_batt_therm(chip, &batt_temp);
        if (rc)
            batt_temp = BMS_DEFAULT_TEMP;

        //如果这次的soc改变变大。并且不处于充电模式,soc跟着last_soc一样，就是排除不充电且电量变大的情况
        if (chip->last_soc < soc && !charging)
            soc = chip->last_soc;
        else if (chip->last_soc < soc && soc != 100)
            //缩小计算的soc与last_soc的进度
            soc = scale_soc_while_chg(chip, charge_time_sec,
                    chip->catch_up_time_sec,
                    soc, chip->chg_start_soc);

        //如果电池接近切断，或者电池温度低于低温阈值，允许更大的变化
        if (bms_wake_active(&chip->vbms_lv_wake_source) ||
            (batt_temp <= chip->dt.cfg_low_temp_threshold))
            soc_change = min((int)abs(chip->last_soc - soc),
                time_since_last_change_sec);
        else
            soc_change = min((int)abs(chip->last_soc - soc),
                time_since_last_change_sec
                    / SOC_CHANGE_PER_SEC);

        if (chip->last_soc_unbound) {
            chip->last_soc_unbound = false;
        } else {
            /*
             * if soc have not been unbound by resume,
             * only change reported SoC by 1.
             */
            soc_change = min(1, soc_change);
        }
        
        
        if (soc < chip->last_soc && soc != 0)
            soc = chip->last_soc - soc_change;
        if (soc > chip->last_soc && soc != 100)
            soc = chip->last_soc + soc_change;
    }

    if (chip->last_soc != soc && !chip->last_soc_unbound)
        chip->last_soc_change_sec = last_change_sec;

    /*
     * Check/update eoc under following condition:
     * if there is change in soc:
     *  soc != chip->last_soc
     * during bootup if soc is 100:
     */
    soc = bound_soc(soc);
    //当电池改变，或者在开机过程中达到100%的电量
    if ((soc != chip->last_soc) || (soc == 100)) {
        chip->last_soc = soc;
        //在这个函数里面，如果report_soc==100的话，还是算是不充电的状态
        //当上一次充电还是100，报告已经充满电了，假设有这个标志的话，qcom,use-reported-soc，会设置eoc_reported为true，这个在之后复充标志的时候有用到
        check_eoc_condition(chip);
        //不充电状态并且设置的复充电量高于0%，这是必备条件
        if ((chip->dt.cfg_soc_resume_limit > 0) && !charging)
            //里面的复充条件是
            check_recharge_condition(chip);
    }

    pr_debug("last_soc=%d calculated_soc=%d soc=%d time_since_last_change=%d\n",
            chip->last_soc, chip->calculated_soc,
            soc, time_since_last_change_sec);

    /*
     * Backup the actual ocv (last_ocv_uv) and not the
     * last_soc-interpolated ocv. This makes sure that
     * the BMS algorithm always uses the correct ocv and
     * can catch up on the last_soc (across reboots).
     * We do not want the algorithm to be based of a wrong
     * initial OCV.
     */

    backup_ocv_soc(chip, chip->last_ocv_uv, chip->last_soc);

    //设备树中的qcom,use-reported-soc
    if (chip->reported_soc_in_use)
        //设置reported_soc为100
        return prepare_reported_soc(chip);

    pr_debug("Reported SOC=%d\n", chip->last_soc);

    return chip->last_soc;
}

2.4 复充、充电、停止充电逻辑

通过阅读设备树知道resume-soc这个节点来控制：

在probe函数中通过宏定SPMI_PROP_READ_OPTIONAL义：

SPMI_PROP_READ_OPTIONAL(cfg_soc_resume_limit, "resume-soc", rc);

cfg_soc_resume_limit分别在以下这几个函数中使用过：

• check_recharge_condition函数，最后也是在report_vm_bms_soc函数中使用的
• report_vm_bms_soc函数：为内核线程中上报的函数，主要电池控制也在这个函数里面
• reported_soc_check_status函数

reported_soc_check_status ->
qpnp_vm_bms_ext_power_changed   //这个是个对调函数，暂时没看到哪里的有调到；

2.4.1 复充模式

以下这些函数都只可能在达到100%的时候才会进入的：

1. check_recharge_condition函数：

static void check_recharge_condition(struct qpnp_bms_chip *chip)
{
    int rc;
    union power_supply_propval ret = {0,};
    int status = get_battery_status(chip);

    if (chip->last_soc > chip->dt.cfg_soc_resume_limit)
        return;

    if (status == POWER_SUPPLY_STATUS_UNKNOWN) {
        pr_debug("Unable to read battery status\n");
        return;
    }

    /* Report recharge to charger for SOC based resume of charging */
    if ((status != POWER_SUPPLY_STATUS_CHARGING) && chip->eoc_reported) {
        ret.intval = POWER_SUPPLY_STATUS_CHARGING;
        rc = chip->batt_psy->set_property(chip->batt_psy,
                POWER_SUPPLY_PROP_STATUS, &ret);
        if (rc < 0) {
            pr_err("Unable to set battery property rc=%d\n", rc);
        } else {
            pr_info("soc dropped below resume_soc soc=%d resume_soc=%d, restart charging\n",
                    chip->last_soc,
                    chip->dt.cfg_soc_resume_limit);
            chip->eoc_reported = false;
        }
    }
}

如果chip->last_soc高于设置的resume-soc复冲电压的话， 那么就return出来；

如果chip->last_soc低于设置的resume-soc复冲电压的话，就设置电源的充电状态，并设置set_property给上层；

我们可以看看这个函数在哪里使用的：

在函数的report_vm_bms_soc上使用的：

if ((soc != chip->last_soc) || (soc == 100)) {
    chip->last_soc = soc;
    check_eoc_condition(chip);
    if ((chip->dt.cfg_soc_resume_limit > 0) && !charging)
        check_recharge_condition(chip);
}

当电压改变的时候，判断不在充电模式且设置的复充电容在95%；

1. check_eoc_condition函数中：

static void check_eoc_condition(struct qpnp_bms_chip *chip)
{
    int rc;
    int status = get_battery_status(chip);
    union power_supply_propval ret = {0,};

    if (status == POWER_SUPPLY_STATUS_UNKNOWN) {
        pr_err("Unable to read battery status\n");
        return;
    }

    /*
     * Check battery status:
     * if last_soc is 100 and battery status is still charging
     * reset ocv_at_100 and force reporting of eoc to charger.
     */
     //检查电池状态，假设上次电池的last_soc为100，并且还在充电状态强制报告eoc到充电器上
    if ((chip->last_soc == 100) &&
            (status == POWER_SUPPLY_STATUS_CHARGING))
        chip->ocv_at_100 = -EINVAL;

    /*
     * Store the OCV value at 100. If the new ocv is greater than
     * ocv_at_100 (battery settles), update ocv_at_100. Else
     * if the SOC drops, reset ocv_at_100.
     */
    if (chip->ocv_at_100 == -EINVAL) {
        //假设上次last_soc为100，报告复充条件符合，第二次达到100%进来的
        if (chip->last_soc == 100) {
            if (chip->dt.cfg_report_charger_eoc) {
                //上报充满电的状态
                rc = report_eoc(chip);
                if (!rc) {
                    /*
                     * update ocv_at_100 only if EOC is
                     * reported successfully.
                     */
                    chip->ocv_at_100 = chip->last_ocv_uv;
                    pr_debug("Battery FULL\n");
                } else {
                    pr_err("Unable to report eoc rc=%d\n",
                            rc);
                    chip->ocv_at_100 = -EINVAL;
                }
            }
            if (chip->dt.cfg_use_reported_soc) {
                /* begin reported_soc process */
                chip->reported_soc_in_use = true;
                chip->charger_removed_since_full = false;
                chip->charger_reinserted = false;
                chip->reported_soc = 100;
                pr_debug("Begin reported_soc process\n");
            }
        }
    } else {
        if (chip->last_ocv_uv >= chip->ocv_at_100) {
            pr_debug("new_ocv(%d) > ocv_at_100(%d) maintaining SOC to 100\n",
                    chip->last_ocv_uv, chip->ocv_at_100);
            chip->ocv_at_100 = chip->last_ocv_uv;
            chip->last_soc = 100;
        } else if (chip->last_soc != 100) {
            /*
             * Report that the battery is discharging.
             * This gets called once when the SOC falls
             * below 100.
             */
            if (chip->reported_soc_in_use
                    && chip->reported_soc == 100) {
                pr_debug("reported_soc=100, last_soc=%d, do not send DISCHARING status\n",
                        chip->last_soc);
            } else {
                ret.intval = POWER_SUPPLY_STATUS_DISCHARGING;
                chip->batt_psy->set_property(chip->batt_psy,
                    POWER_SUPPLY_PROP_STATUS, &ret);
            }
            pr_debug("SOC dropped (%d) discarding ocv_at_100\n",
                            chip->last_soc);
            chip->ocv_at_100 = -EINVAL;
        }
    }
}

设置四个标志位：

• reported_soc_in_use=true
• charger_removed_since_full=false
• charger_reinserted=false
• reported_soc=100 //这个标志位在下文的停止充电中有使用到

这四个标志位之后会在report_vm_bms_soc上的prepare_reported_soc函数上使用；

1. prepare_reported_soc函数

static int prepare_reported_soc(struct qpnp_bms_chip *chip)
{   
    //因为刚刚标志位被设置为false
    if (chip->charger_removed_since_full == false) {
        /*
         * charger is not removed since full,
         * keep reported_soc as 100 and calculate the delta soc
         * between reported_soc and last_soc
         */
        chip->reported_soc = 100;
        chip->reported_soc_delta = 100 - chip->last_soc;
        pr_debug("Keep at reported_soc 100, reported_soc_delta=%d, last_soc=%d\n",
                        chip->reported_soc_delta,
                        chip->last_soc);
    } else {
        /* charger is removed since full */
        if (chip->charger_reinserted) {
            /*
             * charger reinserted, keep the reported_soc
             * until it equals to last_soc.
             */
            if (chip->reported_soc == chip->last_soc) {
                chip->reported_soc_in_use = false;
                chip->reported_soc_high_current = false;
                pr_debug("reported_soc equals to last_soc, stop reported_soc process\n");
            }
            chip->reported_soc_change_sec = 0;
        }
    }
    pr_debug("Reporting reported_soc=%d, last_soc=%d\n",
                    chip->reported_soc, chip->last_soc);
    return chip->reported_soc;
}

2.4.2 停止充电模式

停止充电模式在函数的calculate_reported_soc函数中：

monitor_soc_work -->
    calculate_reported_soc

static void calculate_reported_soc(struct qpnp_bms_chip *chip)
{
    union power_supply_propval ret = {0,};

    if (chip->last_soc < 0) {
        pr_debug("last_soc is not ready, return\n");
        return;
    }

    //这样就是处于充电模式
    if (chip->reported_soc > chip->last_soc) {
        /*send DISCHARGING status if the reported_soc drops from 100 */
        //当充电到100%的时候，设置停止充电的状态，在上面设置标志位的时候使用到
        if (chip->reported_soc == 100) {
            ret.intval = POWER_SUPPLY_STATUS_DISCHARGING;
            chip->batt_psy->set_property(chip->batt_psy,
                POWER_SUPPLY_PROP_STATUS, &ret);
            pr_debug("Report discharging status, reported_soc=%d, last_soc=%d\n",
                    chip->reported_soc, chip->last_soc);
        }
        /*
        * reported_soc_delta is used to prevent
        * the big change in last_soc,
        * this is not used in high current mode
        */
        if (chip->reported_soc_delta > 0)
            chip->reported_soc_delta--;

        if (chip->reported_soc_high_current)
            chip->reported_soc--;
        else
            chip->reported_soc = chip->last_soc
                    + chip->reported_soc_delta;

        pr_debug("New reported_soc=%d, last_soc is=%d\n",
                    chip->reported_soc, chip->last_soc);
    } else {
        chip->reported_soc_in_use = false;
        chip->reported_soc_high_current = false;
        pr_debug("reported_soc equals last_soc,stop reported_soc process\n");
    }
    pr_debug("bms power_supply_changed\n");
    power_supply_changed(&chip->bms_psy);
}

现在我们想一想如何保持将100%的电压一直保持到95%到复充的状态呢？有一个非常重要的标志位charger_removed_since_full：

这个标志位是什么意思呢？字面意思就是当充电器被拔掉的时候是电量满电的；也就是说电量满电的之后（是之后），并且充电器没有拔掉的时候；看一下这个标志位是会在什么时候改变的吧：

static void reported_soc_check_status(struct qpnp_bms_chip *chip)
{
    u8 present;

    present = is_charger_present(chip);
    pr_debug("usb_present=%d\n", present);
    //当没有充电状态，并且false的状态
    if (!present && !chip->charger_removed_since_full) {
        chip->charger_removed_since_full = true;
        pr_debug("reported_soc: charger removed since full\n");
        return;
    }
    if (chip->reported_soc_high_current) {
        pr_debug("reported_soc in high current mode, return\n");
        return;
    }
    if ((chip->reported_soc - chip->last_soc) >
            (100 - chip->dt.cfg_soc_resume_limit
                        + HIGH_CURRENT_TH)) {
        chip->reported_soc_high_current = true;
        chip->charger_removed_since_full = true;
        chip->charger_reinserted = false;
        pr_debug("reported_soc enters high current mode\n");
        return;
    }
    if (present && chip->charger_removed_since_full) {
        chip->charger_reinserted = true;
        pr_debug("reported_soc: charger reinserted\n");
    }
    if (!present && chip->charger_removed_since_full) {
        chip->charger_reinserted = false;
        pr_debug("reported_soc: charger removed again\n");
    }
}

但这个函数也要在一定条件下才能进来，同样也需要reported_soc_in_use标志位来使用：

if (chip->reported_soc_in_use)
        reported_soc_check_status(chip);

最开始的时候reported_soc_in_use已经是true的状态了，只有两种情况会改变它，

1. 在重新插入的情况下，充完了电；
2. 在calculate_reported_soc函数中，属于放电的状态；

3. 流程图