Re: [RESEND PATCH] usb: common: usb-conn-gpio: Register optional charger

[Paul Cercueil <paul@crapouillou.net>]

Le dim. 26 juil. 2020 à 13:14, Andy Shevchenko 
<andy.shevchenko@gmail.com> a écrit :
> On Mon, Jun 22, 2020 at 1:51 AM Paul Cercueil <paul@crapouillou.net> 
> wrote:
>> 
>>  Register a power supply charger, if the Kconfig option
>>  USB_CONN_GPIO_CHARGER is set, whose online state depends on whether
>>  the USB role is set to device or not.
>> 
>>  This is useful when the USB role is the only way to know if the 
>> device
>>  is charging from USB. The API is the standard power supply charger 
>> API,
>>  you get a /sys/class/power_supply/xxx/online node which tells you 
>> the
>>  state of the charger.
>> 
>>  The sole purpose of this is to give userspace applications a way to
>>  know whether or not the charger is plugged.
> 
> I'm not sure I understand the purpose of this (third?) way to detect
> USB charger and notify user space about.
> Why is extcon not good enough?

We can't have extcon and USB role detection at the same time.

-Paul

>>  Signed-off-by: Paul Cercueil <paul@crapouillou.net>
>>  ---
>>   drivers/usb/common/Kconfig         | 11 +++++++
>>   drivers/usb/common/usb-conn-gpio.c | 47 
>> ++++++++++++++++++++++++++++++
>>   2 files changed, 58 insertions(+)
>> 
>>  diff --git a/drivers/usb/common/Kconfig b/drivers/usb/common/Kconfig
>>  index d611477aae41..5405ae96c68f 100644
>>  --- a/drivers/usb/common/Kconfig
>>  +++ b/drivers/usb/common/Kconfig
>>  @@ -49,3 +49,14 @@ config USB_CONN_GPIO
>> 
>>            To compile the driver as a module, choose M here: the 
>> module will
>>            be called usb-conn-gpio.ko
>>  +
>>  +if USB_CONN_GPIO
>>  +
>>  +config USB_CONN_GPIO_CHARGER
>>  +       bool "USB charger support"
>>  +       select POWER_SUPPLY
>>  +       help
>>  +         Register a charger with the power supply subsystem. This 
>> will allow
>>  +         userspace to know whether or not the device is charging 
>> from USB.
>>  +
>>  +endif
>>  diff --git a/drivers/usb/common/usb-conn-gpio.c 
>> b/drivers/usb/common/usb-conn-gpio.c
>>  index ed204cbb63ea..129d48db280b 100644
>>  --- a/drivers/usb/common/usb-conn-gpio.c
>>  +++ b/drivers/usb/common/usb-conn-gpio.c
>>  @@ -17,6 +17,7 @@
>>   #include <linux/of.h>
>>   #include <linux/pinctrl/consumer.h>
>>   #include <linux/platform_device.h>
>>  +#include <linux/power_supply.h>
>>   #include <linux/regulator/consumer.h>
>>   #include <linux/usb/role.h>
>> 
>>  @@ -38,6 +39,9 @@ struct usb_conn_info {
>>          struct gpio_desc *vbus_gpiod;
>>          int id_irq;
>>          int vbus_irq;
>>  +
>>  +       struct power_supply_desc desc;
>>  +       struct power_supply *charger;
>>   };
>> 
>>   /**
>>  @@ -98,6 +102,8 @@ static void usb_conn_detect_cable(struct 
>> work_struct *work)
>>                  ret = regulator_enable(info->vbus);
>>                  if (ret)
>>                          dev_err(info->dev, "enable vbus regulator 
>> failed\n");
>>  +       } else if (IS_ENABLED(CONFIG_USB_CONN_GPIO_CHARGER)) {
>>  +               power_supply_changed(info->charger);
>>          }
>> 
>>          info->last_role = role;
>>  @@ -121,10 +127,35 @@ static irqreturn_t usb_conn_isr(int irq, void 
>> *dev_id)
>>          return IRQ_HANDLED;
>>   }
>> 
>>  +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_conn_info *info = power_supply_get_drvdata(psy);
>>  +
>>  +       switch (psp) {
>>  +       case POWER_SUPPLY_PROP_ONLINE:
>>  +               val->intval = info->last_role == USB_ROLE_DEVICE;
>>  +               break;
>>  +       default:
>>  +               return -EINVAL;
>>  +       }
>>  +
>>  +       return 0;
>>  +}
>>  +
>>   static int usb_conn_probe(struct platform_device *pdev)
>>   {
>>          struct device *dev = &pdev->dev;
>>  +       struct power_supply_desc *desc;
>>          struct usb_conn_info *info;
>>  +       struct power_supply_config cfg = {
>>  +               .of_node = dev->of_node,
>>  +       };
>>          int ret = 0;
>> 
>>          info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
>>  @@ -203,6 +234,22 @@ static int usb_conn_probe(struct 
>> platform_device *pdev)
>>                  }
>>          }
>> 
>>  +       if (IS_ENABLED(CONFIG_USB_CONN_GPIO_CHARGER)) {
>>  +               desc = &info->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;
>>  +               cfg.drv_data = info;
>>  +
>>  +               info->charger = devm_power_supply_register(dev, 
>> desc, &cfg);
>>  +               if (IS_ERR(info->charger)) {
>>  +                       dev_err(dev, "Unable to register 
>> charger\n");
>>  +                       return PTR_ERR(info->charger);
>>  +               }
>>  +       }
>>  +
>>          platform_set_drvdata(pdev, info);
>> 
>>          /* Perform initial detection */
>>  --
>>  2.27.0
>> 
> 
> 
> --
> With Best Regards,
> Andy Shevchenko