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?
> 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
