usb: misc: apple-mfi-fastcharge: Make power supply names unique

When multiple Apple devices are connected concurrently, the
apple-mfi-fastcharge driver fails to probe the subsequent devices with
the following error:

    sysfs: cannot create duplicate filename '/class/power_supply/apple_mfi_fastcharge'
    apple-mfi-fastcharge 5-2.4.3.3: probe of 5-2.4.3.3 failed with error -17

This happens because the driver uses a fixed power supply name
("apple_mfi_fastcharge") for all devices, causing a sysfs name
conflict when a second device is connected.

Fix this by generating unique names using the USB bus and device
number (e.g., "apple_mfi_fastcharge_5-12"). This ensures each
connected device gets a unique power supply entry in sysfs.

The change requires storing a copy of the power_supply_desc structure
in the per-device mfi_device struct, since the name pointer needs to
remain valid for the lifetime of the power supply registration.

Fixes: 249fa8217b84 ("USB: Add driver to control USB fast charge for iOS devices")
Signed-off-by: Charalampos Mitrodimas <charmitro@posteo.net>
Link: https://lore.kernel.org/r/20250602-apple-mfi-fastcharge-duplicate-sysfs-v1-1-5d84de34fac6@posteo.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/misc/apple-mfi-fastcharge.c b/drivers/usb/misc/apple-mfi-fastcharge.c
index ac8695195c13c8752076e4391ac81a9da3780c44..8e852f4b8262e6e8fcd33883be8c5696f19b9ee9 100644 (file)
--- a/drivers/usb/misc/apple-mfi-fastcharge.c
+++ b/drivers/usb/misc/apple-mfi-fastcharge.c
@@ -44,6 +44,7 @@ MODULE_DEVICE_TABLE(usb, mfi_fc_id_table);
 struct mfi_device {
        struct usb_device *udev;
        struct power_supply *battery;
+       struct power_supply_desc battery_desc;
        int charge_type;
 };
 
@@ -178,6 +179,7 @@ static int mfi_fc_probe(struct usb_device *udev)
 {
        struct power_supply_config battery_cfg = {};
        struct mfi_device *mfi = NULL;
+       char *battery_name;
        int err;
 
        if (!mfi_fc_match(udev))
@@ -187,23 +189,38 @@ static int mfi_fc_probe(struct usb_device *udev)
        if (!mfi)
                return -ENOMEM;
 
+       battery_name = kasprintf(GFP_KERNEL, "apple_mfi_fastcharge_%d-%d",
+                                udev->bus->busnum, udev->devnum);
+       if (!battery_name) {
+               err = -ENOMEM;
+               goto err_free_mfi;
+       }
+
+       mfi->battery_desc = apple_mfi_fc_desc;
+       mfi->battery_desc.name = battery_name;
+
        battery_cfg.drv_data = mfi;
 
        mfi->charge_type = POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
        mfi->battery = power_supply_register(&udev->dev,
-                                               &apple_mfi_fc_desc,
+                                               &mfi->battery_desc,
                                                &battery_cfg);
        if (IS_ERR(mfi->battery)) {
                dev_err(&udev->dev, "Can't register battery\n");
                err = PTR_ERR(mfi->battery);
-               kfree(mfi);
-               return err;
+               goto err_free_name;
        }
 
        mfi->udev = usb_get_dev(udev);
        dev_set_drvdata(&udev->dev, mfi);
 
        return 0;
+
+err_free_name:
+       kfree(battery_name);
+err_free_mfi:
+       kfree(mfi);
+       return err;
 }
 
 static void mfi_fc_disconnect(struct usb_device *udev)
@@ -213,6 +230,7 @@ static void mfi_fc_disconnect(struct usb_device *udev)
        mfi = dev_get_drvdata(&udev->dev);
        if (mfi->battery)
                power_supply_unregister(mfi->battery);
+       kfree(mfi->battery_desc.name);
        dev_set_drvdata(&udev->dev, NULL);
        usb_put_dev(mfi->udev);
        kfree(mfi);