高通電源管理qpnp-vm-bms驅動
阿新 • • 發佈：2019-09-27
1. compatible節點：
qpnp-vm-bms.c使用來控制電池曲線的和BMS功能的，其compatible節點是"qcom,qpnp-vm-bms"
2. probe函式：
qpnp_vm_bms_probe函式如下：
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; } //獲取ADC的值 rc = bms_get_adc(chip, spmi); if (rc < 0) { pr_err("Failed to get adc rc=%d\n", rc); return rc; } //指向revision外圍節點的phandle 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的修訂資訊 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; //檢視是否是熱啟動的，熱啟動就是在不關閉裝置的情況下，重啟電腦 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裝置的內容，並且在其中尋找它的中斷基地址 rc = parse_spmi_dt_properties(chip, spmi); if (rc) { pr_err("Error registering spmi resource rc=%d\n", rc); return rc; } //解析電池的引數，如v-cutoff-uv，關機電壓，它不會讀qcom的內容，會直接讀qcom,後面的內容會有仔細說 rc = parse_bms_dt_properties(chip); if (rc) { pr_err("Unable to read all bms properties, rc = %d\n", rc); return rc; } //查詢錯誤的原因 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; } //讀取存在pm？PM裡讀出來的未經修正的原始資料？ 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); //初始化佇列 /* read battery-id and select the battery profile */ //設定電池資料，也就是電池曲線，後面詳細說明 rc = set_battery_data(chip); if (rc) { pr_err("Unable to read battery data %d\n", rc); goto fail_init; } /* set the battery profile */ //設定電池的配置檔案 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，核心睡眠機制 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"); //初始化工作佇列 INIT_DELAYED_WORK(&chip->monitor_soc_work, monitor_soc_work); INIT_DELAYED_WORK(&chip->voltage_soc_timeout_work, voltage_soc_timeout_work); //初始化配置狀態，各種狀態 bms_init_defaults(chip); //這一句看不懂了，可能是電池BMS演算法用來讀取硬體配置的 bms_load_hw_defaults(chip); //通過判斷power_supply裡面的函式來確定是否是正在充電的狀態 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)) { if (is_bat_pres_ght) { //設定電池的設定低電(高電，高溫，低溫)的閾值 rc = setup_vbat_monitoring(chip); if (rc) { pr_err("fail to configure vbat monitoring rc=%d\n", rc); goto fail_setup; } } //請求一些相應的中斷BMS rc = bms_request_irqs(chip); if (rc) { pr_err("error requesting bms irqs, rc = %d\n", rc); goto fail_irq; } //電池一些常規的檢測，主要從PMIC上讀到的相關資訊 //電池的插入狀態檢測 battery_insertion_check(chip); //電池狀態檢測 battery_status_check(chip); /* character device to pass data to the userspace */ //向上層註冊字元裝置 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; //這個也很重要，我們從上節知道，初值last_ocv_soc是非常重要的，決定著後面的soc估值演算法 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); } //設定和註冊電池的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); 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"); } //這裡啟動工作佇列，絕大部分的工作內容都是在這裡完成的 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()函式
在這裡我們詳細分析一下各個節點的內容，這裡就挑幾個比較重要的看看：（詳細可以參考裝置樹裡面的內容）
- v-cutoff-uv：如修改關機電壓，除了修改這裡，還需要修改電池曲線資料的qcom,v-cutoff-uv，其實最好是用電池曲線資料裡的
- max-voltage-uv：電池最大的電壓，單位為毫伏
- qcom,r-conn-mohm ：聯結器的電阻
- s1-sample-interval-ms：狀態s1下累加器的取樣（毫秒）。（即）累加器充滿vbat樣本的速率。最小值=0最大值=2550ms。
- resume-soc：當充滿的電池百分比低於此值，則重新開始充電。
- volatge-soc-timeout-ms：如果沒有使用VMBMS演算法來計算SOC，模組在此時間後基於SOC來報告電壓。
- low-temp-threshold：當溫度閾值低於此值，禁用IBAT求取平均值和UUC(不可用電量)平滑功能，如沒指定預設為0，我們這裡沒有指定。
- qcom,ignore-shutdown-soc：有些不看翻譯對大家都好；
- qcom,use-voltage-soc ：BMS根據此項的值來決定是否採用基於電壓的SOC來替代基於庫倫電量計的方式
- qcom,use-reported-soc ：此項使能reported_soc邏輯，而且要定義qcom,resume-soc為一個合適的值，BMS也需要控制充電、停止充電和重新充電。高通給出的程式碼預設是定義qcom,use-reported-soc，但我們核心板廠家註釋掉此項，並增加qcom,report-charger-eoc
- qcom,report-charger-eoc： 指示BMS需要通知EOC(充電結束)給充電器
- qcom,disable-bms ：此屬性用於關閉VM BMS硬體模組
2.2 set_battery_data()函式
這一部分內容就是設定電池曲線內容：
下面就是電池曲線的詳細內容，不仔細說了：
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;
//裡面的內容通過讀取ADC來獲取ID號
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;
}
2.3 高通電量計
| 術語 | 全稱 | 註釋 |
|---|---|---|
| FCC | Full-Charge Capacity | 滿電荷電量 |
| UC | Remaining capacity | RC 剩餘電量 |
| CC | Coulumb counter | 電量計 |
| UUC | Unusable capacity | 不可用電量 |
| RUC | Remaining usable capacity // | RUC=RC-CC-UUC RUC=RC-CC-UUC，剩餘可用電量 |
| SoC | State of charge | 電量百分比 |
| OCV | Open circuit voltage | 開路電壓，電池在開路狀態下的端電壓稱為開路電壓 |
SOC=(RC-CC-UUC)/(FCC-UUC)
以下是各個變數的計算方法：
2.3.1 FCC：
在校準的電池profile中有定義,會隨溫度有變化；
static struct single_row_lut fcc_temp = {
.x = {-20, 0, 25, 40, 60},
.y = {3193, 3190, 3190, 3180, 3183},
.cols = 5
}對應電池曲線的qcom,fcc-temp-lut；
2.3.2 pc-temp-ocv-lut:
qcom,pc-temp-ocv-lut，為溫度、SOC對應得電壓表，PMU8909獲取的電壓值，通過查該表，在溫度和電壓下，可得到當前的SOC。
對應電池曲線的qcom,pc-temp-ocv-lut
2.3.3 rbatt-sf-lut:
rbatt-sf-lut，為溫度、soc對應的電池內阻表，這裡主要考慮內阻的影響，對OCV的修正，new_ocv=ocv+rbatt(內阻)*current（當前電流）。
對應電池曲線的qcom,rbatt-sf-lut
2.3.3 ibat-acc-luit
ibat-acc-luit，為溫度、電流對應的acc表，這兩個是起到修正SOC的作用
對應電池曲線的qcom, ibat-acc-luit
2.3.4 計算公式
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));//最終soc_acc，為上報的SOC.soc_ocv則是在qcom,pc-temp-ocv-lut查表可知
2.3.5 BMS演算法
會上報事件uevent，當HAL層，收到訊息，然後呼叫getprop的方法，獲取相關的引數，如，電阻、電流、fcc、acc等，來估算出last_ocv_uv，然後呼叫setprop，把該值設下去，並啟動工作執行緒，根據last_ocv_uv，查表得到soc，並經過修正SOC，並再次上報事件，迴圈下去。這個估值演算法，我猜可能是一套學習演算法，具體的沒有原始碼，不清楚，只知道它把演算法變為.bin檔案，用了binder機制，作為服務一直執行。
2.3.6 分析如何確定初始的last_ocv_uv：
static int calculate_initial_soc(struct qpnp_bms_chip *chip)
{
........
........
//讀當前電池溫度
rc = get_batt_therm(chip, &batt_temp);
............
//讀PON OCV
rc = read_and_update_ocv(chip, batt_temp, true);
..........
//讀關機儲存的soc和last_soc_uv
rc = read_shutdown_ocv_soc(chip);
//這裡判斷是使用估計soc還是估值soc。如果chip->warm_reset 為真
if (chip->warm_reset) {
if (chip->shutdown_soc_invalid) { //這個是dtsi的一個配置選項，若沒有配置，
//則不使用關機soc
est_ocv = estimate_ocv(chip); //估值soc
chip->last_ocv_uv = est_ocv;
} else {
chip->last_ocv_uv = chip->shutdown_ocv;//使用關機的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; //使用關機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); //讀ADC值
uv = adjust_vbatt_reading(chip, uv); //轉化為soc_uv
rc = qpnp_vbat_sns_comp_result(chip->vadc_dev, &uv, is_pon_ocv); //根據IC的型別，進行溫度補償
//從暫存器中讀到儲存的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); //根據ocv和temp，查表得PC(soc)。
rbatt_mohm = get_rbatt(chip, pc, batt_temp); //根據soc和temp，得電池內阻值
/* convert die_temp to DECIDEGC */
die_temp = (int)result.physical / 100;
current_ma = interpolate_current_comp(die_temp); //當前電流
delta_uv = rbatt_mohm * current_ma;
chip->last_ocv_uv += delta_uv; //修正last_ocv_uv
//這個函式主要根據last_ocv_uv，計算出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);
//計算出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; //這個為上報的soc
chip->last_acc = acc;2.3.7 工作佇列monitor_soc_work
static void monitor_soc_work(struct work_struct *work)
calculate_delta_time(&chip->tm_sec, &chip->delta_time_s);
rc = get_batt_therm(chip, &batt_temp);
new_soc = lookup_soc_ocv(chip, chip->last_ocv_uv,batt_temp);
new_soc = clamp_soc_based_on_voltage(chip, new_soc);
report_vm_bms_soc(chip);//上報事件，上層得到訊息，呼叫qpnp_vm_bms_power_get_property，獲取相關的屬性，計算出
last_ocv_uv,並通過qpnp_vm_bms_power_set_property方法，設定last_ocv_uv，並啟動monitor_soc_work。
2.4 復充、充電、停止充電邏輯
通過閱讀裝置樹知道resume-soc這個節點來控制：
在probe函式中通過巨集定SPMI_PROP_READ_OPTIONAL義：
SPMI_PROP_READ_OPTIONAL(cfg_soc_resume_limit, "resume-soc", rc);cfg_soc_resume_limit分別在以下這幾個函式中使用過：
- check_recharge_condition函式，最後也是在report_vm_bms_soc函式中使用的
- report_vm_bms_soc函式：為核心執行緒中上報的函式，主要電池控制也在這個函式裡面
- reported_soc_check_status函式
reported_soc_check_status ->
qpnp_vm_bms_ext_power_changed //這個是個對調函式，暫時沒看到哪裡的有調到；2.4.1 復充模式
check_recharge_condition函式：
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高於設定的resume-soc復衝電壓的話， 那麼就return出來；
如果chip->last_soc低於設定的resume-soc復衝電壓的話，就設定電源的充電狀態，並設定set_property給上層；
我們可以看看這個函式在哪裡使用的：
在函式的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);
}當電壓改變的時候，判斷不在充電模式且設定的復充電容在95%；
2.4.2 停止充電模式
停止充電模式在函式的calculate_reported_soc函式中：
monitor_soc_work -->
calculate_reported_socstatic 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;
}
//這樣就是處於充電模式
if (chip->reported_soc > chip->last_soc) {
/*send DISCHARGING status if the reported_soc drops from 100 */
//當充電到100%的時候，設定停止充電的狀態
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);
}我們如何知道monitor_soc_work函式不斷的執行呢？
原因在於：
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)));
}