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

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Date:   Tue, 17 Dec 2019 01:32:23 +0000
From:   Peter Chen <peter.chen@....com>
To:     Paul Cercueil <paul@...pouillou.net>
CC:     Sebastian Reichel <sre@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "od@...c.me" <od@...c.me>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>
Subject: RE: [PATCH v2 3/3] power/supply: Add generic USB charger driver

 
> Le lun., déc. 16, 2019 at 01:24, Peter Chen <peter.chen@....com> 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@...40000 {
> 	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'.
> 

Thanks for explaining it.

What's the user for this USB charger,  PMIC or what else? How the user uses
this USB charger interface?

Peter

> 
> 
> >>  >
> >>  >>  +
> >>  >>  +	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@...pouillou.net>");
> >>  >> +MODULE_LICENSE("GPL");
> >>  >>  --
> >>  >>  2.24.0
> >>  >>
> >>  >
> >>  > --
> >>  >
> >>  > Thanks,
> >>  > Peter Chen
> >>
> >
>