RE: [PATCH v2 3/3] power/supply: Add generic USB charger driver

From: Paul Cercueil
Date: Mon Dec 16 2019 - 05:52:16 EST


Hi Peter,


Le lun., déc. 16, 2019 at 01:24, Peter Chen <peter.chen@xxxxxxx> a écrit :

>> +
>> + desc = &charger->desc;
>> + desc->name = "usb-charger";
>> + desc->properties = usb_charger_properties;
>> + desc->num_properties = ARRAY_SIZE(usb_charger_properties);
>> + desc->get_property = usb_charger_get_property;
>> + desc->type = POWER_SUPPLY_TYPE_USB;
>
> What's your further plan for this generic USB charger?
> To support BC1.2, we need to know charger type, and how we could get
> it?
>
> Peter

Well I don't really know. The USB role framework does not give any info about
what's plugged.


What's the use case for this patch set? How it be used?

My devicetree:

usb_otg: usb@13440000 {
compatible = "ingenic,jz4770-musb", "simple-mfd";
reg = <0x13440000 0x10000>;
[...]

usb-role-switch;

connector {
compatible = "gpio-usb-b-connector", "usb-b-connector";
label = "mini-USB";
type = "mini";

id-gpios = <&gpf 18 GPIO_ACTIVE_HIGH>;
vbus-gpios = <&gpb 5 GPIO_ACTIVE_HIGH>;
[...]
};

usb_charger: usb-charger {
compatible = "usb-charger";
};
};

The new gpio-usb-connector driver uses the ID/VBUS GPIOs to detect in which state (device, host, unconnected) a OTG connector is. However, that means I cannot use the standard gpio-charger driver to detect the presence of a charger based on the state of the VBUS gpio, since it's already requested here. So the point of this patchset is to provide an alternative to gpio-charger that works with OTG controllers compatible with 'usb-role-switch'.

Cheers,
-Paul


>
>> +
>> + charger->charger = devm_power_supply_register(dev, desc, &cfg);
>> + if (IS_ERR(charger->charger)) {
>> + dev_err(dev, "Unable to register charger");
>> + return PTR_ERR(charger->charger);
>> + }
>> +
>> + err = usb_role_switch_register_notifier(charger->role,
>> &charger->nb);
>> + if (err) {
>> + dev_err(dev, "Unable to register USB role switch notifier");
>> + return err;
>> + }
>> +
>> + return devm_add_action_or_reset(dev, usb_charger_unregister,
>> charger);
>> +}
>> +
>> +static const struct of_device_id usb_charger_of_match[] = {
>> + { .compatible = "usb-charger" },
>> + { /* sentinel */ },
>> +};
>> +MODULE_DEVICE_TABLE(of, usb_charger_of_match); + +static struct
>> platform_driver usb_charger_driver = {
>> + .driver = {
>> + .name = "usb-charger",
>> + .of_match_table = of_match_ptr(usb_charger_of_match),
>> + },
>> + .probe = usb_charger_probe,
>> +};
>> +module_platform_driver(usb_charger_driver);
>> +
>> +MODULE_DESCRIPTION("Simple USB charger driver");
>> +MODULE_AUTHOR("Paul Cercueil <paul@xxxxxxxxxxxxxxx>");
>> +MODULE_LICENSE("GPL");
>> --
>> 2.24.0
>>
>
> --
>
> Thanks,
> Peter Chen