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

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Hi Peter,


Le jeu., déc. 12, 2019 at 09:18, Peter Chen <peter.chen@xxxxxxx> a écrit :
On 19-12-11 16:50:32, Paul Cercueil wrote:
This simple charger driver uses the USB role switch framework to detect the presence of a charger. The USB charger will report as online when
 the USB role is set to device, and offline otherwise.

 Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
 ---

 Notes:
v2: Instead of detecting charger state from USB PHY, we detect it from the
         USB role in use.

  drivers/power/supply/Kconfig               |   8 ++
  drivers/power/supply/Makefile              |   1 +
drivers/power/supply/generic-usb-charger.c | 124 +++++++++++++++++++++
  3 files changed, 133 insertions(+)
  create mode 100644 drivers/power/supply/generic-usb-charger.c

diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
 index 27164a1d3c7c..c4221bcabee4 100644
 --- a/drivers/power/supply/Kconfig
 +++ b/drivers/power/supply/Kconfig
 @@ -51,6 +51,14 @@ config GENERIC_ADC_BATTERY
  	  Say Y here to enable support for the generic battery driver
  	  which uses IIO framework to read adc.

 +config GENERIC_USB_CHARGER
 +	tristate "Generic USB charger"
 +	depends on USB_SUPPORT
 +	select USB_ROLE_SWITCH
 +	help
 +	  Say Y here to enable a generic USB charger driver which uses
+ the USB role switch framework to detect the presence of the charger.
 +
  config MAX8925_POWER
  	tristate "MAX8925 battery charger support"
  	depends on MFD_MAX8925
diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
 index 6c7da920ea83..03f9b553bdfc 100644
 --- a/drivers/power/supply/Makefile
 +++ b/drivers/power/supply/Makefile
@@ -8,6 +8,7 @@ power_supply-$(CONFIG_LEDS_TRIGGERS) += power_supply_leds.o
  obj-$(CONFIG_POWER_SUPPLY)	+= power_supply.o
  obj-$(CONFIG_POWER_SUPPLY_HWMON) += power_supply_hwmon.o
  obj-$(CONFIG_GENERIC_ADC_BATTERY)	+= generic-adc-battery.o
 +obj-$(CONFIG_GENERIC_USB_CHARGER)	+= generic-usb-charger.o

  obj-$(CONFIG_PDA_POWER)		+= pda_power.o
  obj-$(CONFIG_APM_POWER)		+= apm_power.o
diff --git a/drivers/power/supply/generic-usb-charger.c b/drivers/power/supply/generic-usb-charger.c
 new file mode 100644
 index 000000000000..0493fafbd4c0
 --- /dev/null
 +++ b/drivers/power/supply/generic-usb-charger.c
 @@ -0,0 +1,124 @@
 +// SPDX-License-Identifier: GPL-2.0
 +/*
 + * Simple USB charger driver
 + * Copyright (c) 2019 Paul Cercueil <paul@xxxxxxxxxxxxxxx>
 + */
 +
 +#include <linux/device.h>
 +#include <linux/module.h>
 +#include <linux/of.h>
 +#include <linux/platform_device.h>
 +#include <linux/power_supply.h>
 +#include <linux/usb/role.h>
 +
 +struct usb_charger {
 +	struct notifier_block nb;
 +	struct usb_role_switch *role;
 +	struct power_supply_desc desc;
 +	struct power_supply *charger;
 +};
 +
 +static enum power_supply_property usb_charger_properties[] = {
 +	POWER_SUPPLY_PROP_ONLINE,
 +};
 +
 +static int usb_charger_get_property(struct power_supply *psy,
 +				    enum power_supply_property psp,
 +				    union power_supply_propval *val)
 +{
 +	struct usb_charger *charger = power_supply_get_drvdata(psy);
 +	enum usb_role role;
 +
 +	switch (psp) {
 +	case POWER_SUPPLY_PROP_ONLINE:
 +		role = usb_role_switch_get_role(charger->role);
 +		val->intval = role == USB_ROLE_DEVICE;
 +		break;
 +	default:
 +		return -EINVAL;
 +	}
 +
 +	return 0;
 +}
 +
 +static int usb_charger_event(struct notifier_block *nb,
 +			     unsigned long event, void *d)
 +{
+ struct usb_charger *charger = container_of(nb, struct usb_charger, nb);
 +
 +	power_supply_changed(charger->charger);
 +
 +	return 0;
 +}
 +
 +static void usb_charger_unregister(void *data)
 +{
 +	struct usb_charger *charger = data;
 +
 +	usb_role_switch_unregister_notifier(charger->role, &charger->nb);
 +}
 +
 +static int usb_charger_probe(struct platform_device *pdev)
 +{
 +	struct device *dev = &pdev->dev;
 +	struct power_supply_desc *desc;
 +	struct usb_charger *charger;
 +	struct power_supply_config cfg = {
 +		.of_node = dev->of_node,
 +	};
 +	int err;
 +
 +	charger = devm_kzalloc(dev, sizeof(*charger), GFP_KERNEL);
 +	if (!charger)
 +		return -ENOMEM;
 +
 +	cfg.drv_data = charger;
 +	charger->nb.notifier_call = usb_charger_event;
 +
 +	charger->role = usb_role_switch_get(dev);
 +	if (IS_ERR(charger->role)) {
 +		if (PTR_ERR(charger->role) != -EPROBE_DEFER)
 +			dev_err(dev, "Unable to get USB role");
 +		return PTR_ERR(charger->role);
 +	}
 +
 +	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.

-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






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