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

[Paul Cercueil <paul@xxxxxxxxxxxxxxx>]

Le dim. 26 juil. 2020 à 13:14, Andy Shevchenko 
<andy.shevchenko@xxxxxxxxx> a écrit :
> On Mon, Jun 22, 2020 at 1:51 AM Paul Cercueil <paul@xxxxxxxxxxxxxxx> 
> 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@xxxxxxxxxxxxxxx>
> >  ---
> >   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