上一篇主要讲电池相关的一些知识，上节忘记讲了，电池一般分为电量计电池和非电流计电池，电量计电池，就不需要用pmu8916的IC，当然这只是只，不需要BMS来计算soc，而jni层也需要读取电流计的电池相关属性。
这一节主要是根据代码进行相关的分析。
- 先看probe的代码：
static int qpnp_vm_bms_probe(struct spmi_device *spmi)
{
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//这里把电池的配置文件dtsi的读出来，并存到当前的结构体。
rc = set_battery_data(chip);
rc = config_battery_data(chip->batt_data);
..........
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//这个是核心的工作，一个线程，BMS的主要内容在此
INIT_DELAYED_WORK(&chip->monitor_soc_work, monitor_soc_work);
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//电池一些常规的检测，主要从PMIC上读到的相关信息
battery_insertion_check(chip);
battery_status_check(chip);
/* character device to pass data to the userspace */
rc = register_bms_char_device(chip);
if (rc) {
pr_err("Unable to regiter '/dev/vm_bms' rc=%d
", 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
calculate_initial_soc(chip);
//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);
rc = power_supply_register(chip->dev, &chip->bms_psy);
if (rc < 0) {
pr_err("power_supply_register bms failed rc = %d
", rc);
goto fail_psy;
}
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//这里启动工作线程
schedule_delayed_work(&chip->monitor_soc_work, 0);
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}
- 分析如何确定初始的last_ocv_uv：
static int calculate_initial_soc(struct qpnp_bms_chip *chip)
{
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//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
", __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
}
}
.............
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}
//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zhi
/* 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;
- 看工作线程，monitor_soc_work(struct work_struct *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);//上报事件，上层得到消息，调用qpnp_vm_bms_power_get_property，获取相关的属性，计算出
last_ocv_uv,并通过qpnp_vm_bms_power_set_property方法，设置last_ocv_uv，并启动monitor_soc_work。
- 待续