linux下充电IC OTG设备供电控制

备注：下面提到的充电IC 用charger表示

1.     OTG VBUS 5V供电

接入OTG设备，比如U盘，具体是怎么通过charger驱动来给U盘供电5V的

2.     设备树

charger:xxx@6B{

regulator-name = " xxx_otg_vreg";

…

};

&usb_otg {

…

vbus_otg-supply = ;

};

3.     调用流程

3.1  usb otg驱动

对应phy-msm-usb.c文件，usb otg驱动加载的时候，调用msm_otg_set_host()，此函数通过：

vbus_otg =devm_regulator_get(motg->phy.dev, "vbus_otg");

通过supply name，这里是vbus_otg-supply，找到regulator设备节点，这里是xxx_otg_supply，调用之后让vbus_otg指向给otg vbus供电的regulator，

devm_regulator_get的调用流程：

devm_regulator_get(motg->phy.dev,"vbus_otg")--->regulator_get()

--->_regulator_get()--->regulator_dev_lookup()--->of_get_regulator()

/**

*of_get_regulator - get a regulator device node based on supply name

*@dev: Device pointer for the consumer (of regulator) device

*@supply: regulator supply name

*

*Extract the regulator device node corresponding to the supply name.

*returns the device node corresponding to the regulator if found, else

*returns NULL.

*/

static struct device_node*of_get_regulator(struct device *dev, const char *supply)

{

structdevice_node *regnode = NULL;

charprop_name[32]; /* 32 is max size of property name */

dev_dbg(dev,"Looking up %s-supply from device tree\n", supply);

snprintf(prop_name,32, "%s-supply", supply);

regnode= of_parse_phandle(dev->of_node, prop_name, 0);

if(!regnode) {

dev_dbg(dev,"Looking up %s property in node %s failed",

prop_name,dev->of_node->full_name);

returnNULL;

}

returnregnode;

}

通过节点xxx下的regulator-name找到regulator的名字为xxx_otg_vreg，

Usb otg驱动找到xxx_otg_vreg这个regulator后，在接入OTG设备时，会调用其对应的regulator_desc(描述regulator的静态信息，包括：名字、supply regulator的名字、中断号、操作函数集(structregulator_ops))下的操作表ops下的enable()，拔出OTG设备时调用disable()

msm_hsusb_vbus_power()--->regulator_enable(vbus_otg)

那enable()和disable()具体在charger驱动中实现。

3.2  charger驱动

(1)  驱动初始化

调用regulator_register()向regulator框架层注册一个regulator设备，用regulator_dev结构体表示。

struct regulator_ops xxx_otg_reg_ops = {

.enable = xxx_otg_regulator_enable,

.disable = xxx_otg_regulator_disable,

.is_enabled = xxx_otg_regulator_is_enable,

};

static int xxx_regulator_init(struct xxx_device_info*chip)

{

intrc = 0;

structregulator_init_data *init_data;

structregulator_config cfg = {};

init_data= of_get_regulator_init_data(chip->dev, chip->dev->of_node);

if(!init_data) {

dev_err(chip->dev,"Unable to allocate memory\n");

return-ENOMEM;

}

if(init_data->constraints.name) {

chip->otg_vreg.rdesc.owner= THIS_MODULE;

chip->otg_vreg.rdesc.type= REGULATOR_VOLTAGE;

chip->otg_vreg.rdesc.ops= &xxx_otg_reg_ops;

chip->otg_vreg.rdesc.name= init_data->constraints.name;

cfg.dev= chip->dev;

cfg.init_data= init_data;

cfg.driver_data= chip;

cfg.of_node= chip->dev->of_node;

init_data->constraints.valid_ops_mask

|=REGULATOR_CHANGE_STATUS;

chip->otg_vreg.rdev= regulator_register(

&chip->otg_vreg.rdesc,&cfg);

if(IS_ERR(chip->otg_vreg.rdev)) {

rc= PTR_ERR(chip->otg_vreg.rdev);

chip->otg_vreg.rdev= NULL;

if(rc != -EPROBE_DEFER)

dev_err(chip->dev,

"OTGreg failed, rc=%d\n", rc);

}

}

returnrc;

}

(2)  插拔OTG设备

比如插入OTG设备时，usb otg驱动通过调用名为xxx_otg_vreg的regulator的enable，来实现otg vbus的供电，对应调用xxx_otg_regulator_enable()。