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Message-Id: <1576270147.3.0@crapouillou.net>
Date: Fri, 13 Dec 2019 21:49:07 +0100
From: Paul Cercueil <paul@...pouillou.net>
To: Peter Chen <peter.chen@....com>
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,
linux-pm@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org
Subject: Re: [PATCH v2 3/3] power/supply: Add generic USB charger driver
Hi Peter,
Le jeu., déc. 12, 2019 at 09:18, Peter Chen <peter.chen@....com> 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@...pouillou.net>
>> ---
>>
>> 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@...pouillou.net>
>> + */
>> +
>> +#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@...pouillou.net>");
>> +MODULE_LICENSE("GPL");
>> --
>> 2.24.0
>>
>
> --
>
> Thanks,
> Peter Chen
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