本文转载自：http://www.voidcn.com/blog/yanleizhouqing/article/p-6051912.html

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。

1. 先看probe的代码：

static int qpnp_vm_bms_probe(struct spmi_device *spmi){	...........	..........	...........	..........	//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);	..........	..........	//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);	..........	..........	//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\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	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\n", rc);		goto fail_psy;	}	.....................	....................	....................	//这里启动工作线程	schedule_delayed_work(&chip->monitor_soc_work, 0);	..........................	.......................}

2. 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;

3. 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。

4. 待续

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高通8X16电池BMS算法（二）【转】