linux 电源管理驱动编写

执行流程

驱动结构

1) 内核提供的接口

struct power_supply 在文件 include\linux\power_supply.h 中

2) 提供给用户的接口

sys/class/power_supply

通过 drivers\power\power_supply_core.c 中的

int power_supply_register(struct device *parent,struct power_supply *psy)

来创建.

power_supply_register() 在 K:\linux学习资料\bible\驱动程序开发\电源电池管理\电源电池管理.pdf中介绍

当电源变化时,调用:drivers\power\power_supply_core.c 中的

power_supply_changed()更新sysfs文件系统中的信息.

把握以上两点!

1. 填充 struct power_supply

路径: include/linux/power_supply.h

1.) 结构体含义

struct power_supply { const char *name;               // 名字,例如: "usb", "battary", "ac"  enum power_supply_type type;    // 电源类型,在power_supply.h定义,分为usb,battery,ups,mains四种 enum power_supply_property *properties;  // 电源属性,比较多,常用的在后面介绍.枚举类型数组 size_t num_properties;            // 属性数量,假设为3,则回调get_property()3次 char **supplied_to; size_t num_supplicants; int (*get_property)(struct power_supply *psy,        // 回调函数,执行power_supply_changed()后被     enum power_supply_property psp,     // 调用,调用次数由num_properties决定     union power_supply_propval *val); int (*set_property)(struct power_supply *psy,     enum power_supply_property psp,     const union power_supply_propval *val); int (*property_is_writeable)(struct power_supply *psy,      enum power_supply_property psp); void (*external_power_changed)(struct power_supply *psy); void (*set_charged)(struct power_supply *psy); /* For APM emulation, think legacy userspace. */ int use_for_apm; /* private */ struct device *dev; struct work_struct changed_work;    // 工作队列,相当于一个线程,由它发起power_supply_changed() spinlock_t changed_lock; bool changed; struct wake_lock work_wake_lock; #ifdef CONFIG_LEDS_TRIGGERS struct led_trigger *charging_full_trig; char *charging_full_trig_name; struct led_trigger *charging_trig; char *charging_trig_name; struct led_trigger *full_trig; char *full_trig_name; struct led_trigger *online_trig; char *online_trig_name; #endif };

2) 常用的power_supply_propety

android下用到的:

# cat /sys/class/power_supply/ac/type Mains # cat /sys/class/power_supply/ac/online 1 # cd /sys/class/power_supply/battery/ # cat type status health present technology capacity Battery Charging Good 1 Li-ion 50

这些宏已经定义过:

enum { // 对应 POWER_SUPPLY_PROP_STATUS        POWER_SUPPLY_STATUS_UNKNOWN = 0,        POWER_SUPPLY_STATUS_CHARGING,        POWER_SUPPLY_STATUS_DISCHARGING,        POWER_SUPPLY_STATUS_NOT_CHARGING,        POWER_SUPPLY_STATUS_FULL, }; enum {   // 对应 POWER_SUPPLY_PROP_CHARGE_TYPE        POWER_SUPPLY_CHARGE_TYPE_UNKNOWN = 0,        POWER_SUPPLY_CHARGE_TYPE_NONE,        POWER_SUPPLY_CHARGE_TYPE_TRICKLE,        POWER_SUPPLY_CHARGE_TYPE_FAST, }; enum { // 对应 POWER_SUPPLY_PROP_HEALTH        POWER_SUPPLY_HEALTH_UNKNOWN = 0,        POWER_SUPPLY_HEALTH_GOOD,        POWER_SUPPLY_HEALTH_OVERHEAT,        POWER_SUPPLY_HEALTH_DEAD,        POWER_SUPPLY_HEALTH_OVERVOLTAGE,        POWER_SUPPLY_HEALTH_UNSPEC_FAILURE,        POWER_SUPPLY_HEALTH_COLD, }; enum {  // 对应 POWER_SUPPLY_PROP_TECHNOLOGY        POWER_SUPPLY_TECHNOLOGY_UNKNOWN = 0,        POWER_SUPPLY_TECHNOLOGY_NiMH,        POWER_SUPPLY_TECHNOLOGY_LION,        POWER_SUPPLY_TECHNOLOGY_LIPO,        POWER_SUPPLY_TECHNOLOGY_LiFe,        POWER_SUPPLY_TECHNOLOGY_NiCd,        POWER_SUPPLY_TECHNOLOGY_LiMn, }; enum { // 对应 POWER_SUPPLY_PROP_CAPACITY_LEVEL         POWER_SUPPLY_CAPACITY_LEVEL_UNKNOWN = 0,        POWER_SUPPLY_CAPACITY_LEVEL_CRITICAL,        POWER_SUPPLY_CAPACITY_LEVEL_LOW,        POWER_SUPPLY_CAPACITY_LEVEL_NORMAL,        POWER_SUPPLY_CAPACITY_LEVEL_HIGH,        POWER_SUPPLY_CAPACITY_LEVEL_FULL, };

一个struct power_supply的例子:

struct max17040_chip {         struct power_supply             battery;      // 三种供电方式         struct power_supply             ac;         struct power_supply             usb;         struct timespec         next_update_time;         struct delayed_work             work;     // 两个队列 struct delayed_work battary_vol_state_wq;         /* State Of Connect */         int online;         /* battery voltage */         int vcell;         /* battery capacity */         int soc;         /* State Of Charge */         int status;         /* usb online */         int usb_online; }; struct max17040_chip *chip;

初始化:

chip->battery.name              = "battery";         chip->battery.type              = POWER_SUPPLY_TYPE_BATTERY;          chip->battery.get_property      = max17040_get_property;  // 回调函数,执行power_supply_changed()后被调用,调用次数由battery.num_properties决定, 函数内容在下面.         chip->battery.properties        = max17040_battery_props;  // 内容在下面         chip->battery.num_properties    = ARRAY_SIZE(max17040_battery_props);         chip->battery.external_power_changed = NULL;         chip->ac.name           = "ac";         chip->ac.type           = POWER_SUPPLY_TYPE_MAINS;         chip->ac.get_property   = adapter_get_property;         chip->ac.properties     = adapter_get_props;         chip->ac.num_properties = ARRAY_SIZE(adapter_get_props);         chip->ac.external_power_changed = NULL;         chip->usb.name          = "usb";         chip->usb.type          = POWER_SUPPLY_TYPE_USB;         chip->usb.get_property  = usb_get_property;         chip->usb.properties    = usb_get_props;         chip->usb.num_properties        = ARRAY_SIZE(usb_get_props);         chip->usb.external_power_changed = NULL; // 两个队列         INIT_DELAYED_WORK_DEFERRABLE(&chip->work, work_max17040);         INIT_DELAYED_WORK_DEFERRABLE(&chip->battary_vol_state_wq, work_battary_vol_sample);         schedule_delayed_work(&chip->work, MAX17040_DELAY);         schedule_delayed_work(&chip->battary_vol_state_wq, POLLING_BATTARY_VOL_MSEC);

max17040_battery_props[] 枚举类型数组内容

static enum power_supply_property max17040_battery_props[] = {   // 一共有7项,                                            // 意味着max17040_get_property()将被回调7次         POWER_SUPPLY_PROP_PRESENT,         POWER_SUPPLY_PROP_STATUS,         /*POWER_SUPPLY_PROP_ONLINE,*/         POWER_SUPPLY_PROP_VOLTAGE_NOW,         POWER_SUPPLY_PROP_CAPACITY,         POWER_SUPPLY_PROP_TECHNOLOGY,         POWER_SUPPLY_PROP_HEALTH,         POWER_SUPPLY_PROP_TEMP, };

max17040_get_property() 函数:

static int max17040_get_property(struct power_supply *psy,                             enum power_supply_property psp,                             union power_supply_propval *val) {   dev_info(dev,"%s \n", __func__);            switch (psp) {       // 一共有7项, 将被回调7次. 执行power_supply_changed()后被回调.                            case POWER_SUPPLY_PROP_STATUS:                 val->intval = chip->status;                 break;         case POWER_SUPPLY_PROP_ONLINE:                 val->intval = 1;                 break;         case POWER_SUPPLY_PROP_VOLTAGE_NOW:         case POWER_SUPPLY_PROP_PRESENT:                 val->intval = 3800;//chip->vcell;                 if(psp  == POWER_SUPPLY_PROP_PRESENT)                         val->intval = 1; /* You must never run Odrioid1 without Battery. */                 break;         case POWER_SUPPLY_PROP_CAPACITY:                 val->intval = 80;//chip->soc;                 break;          case POWER_SUPPLY_PROP_TECHNOLOGY:                 val->intval = POWER_SUPPLY_TECHNOLOGY_LION;                 break;          case POWER_SUPPLY_PROP_HEALTH: //              if(chip->vcell  < 2850) //                      val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE; //              else                          val->intval = POWER_SUPPLY_HEALTH_GOOD;                 break;         case POWER_SUPPLY_PROP_TEMP:                 break;         default:                 return -EINVAL;         }         return 0; }

work_queue队列

static void work_max17040(struct work_struct *work) {         int old_usb_online, old_online, old_vcell, old_soc; int vol, level;         old_online = chip->online;         old_usb_online = chip->usb_online;         old_vcell = chip->vcell;         old_soc = chip->soc;         max17040_update_values(); vol = battary_vol_average(); printk("+++ %s: vol = %d \n", __func__, vol); level = battary_level(vol); dev_info(dev,"%s, level = %d \n", __func__, level); //      s3c_get_bat_level(); /*         if((old_vcell != chip->vcell) || (old_soc != chip->soc))                 power_supply_changed(&chip->battery);         if(old_usb_online != chip->usb_online)                 power_supply_changed(&chip->usb);         if(old_online != chip->online)                 power_supply_changed(&chip->ac); */         power_supply_changed(&chip->ac);    // 回调ac 中的get_property() // for test power_supply_changed(&chip->battery);  // 回调battery中的get_property() power_supply_changed(&chip->usb);  // 回调usb中的get_property() //         schedule_delayed_work(&chip->work, MAX17040_DELAY); }