[v2] leds: fix regression in usbport led trigger

[Christian Lamparter <chunkeey@gmail.com>]

The patch "usb: simplify usbport trigger" together with
"leds: triggers: add device attribute support" caused an
regression for the usbport trigger. it will no longer
enumerate any active usb hub ports under the "ports"
directory in the sysfs class directory, if the usb host
drivers are fully initialized before the usbport trigger
was loaded.

The reason is that the usbport driver tries to register
the sysfs entries during the activate() callback. And this
will fail with -2 / ENOENT because the patch
"leds: triggers: add device attribute support" made it so
that the sysfs "ports" group was only being added after
the activate() callback succeeded.

This version of the patch reverts parts of the
"usb: simplify usbport trigger" patch and restores
usbport trigger's functionality.

Fixes: 6f7b0bad8839 ("usb: simplify usbport trigger")
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Acked-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
---
Let's see if linux-usb is still on holiday or not ;).
---
 drivers/usb/core/ledtrig-usbport.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/core/ledtrig-usbport.c b/drivers/usb/core/ledtrig-usbport.c
index dc7f7fd71684..c12ac56606c3 100644
--- a/drivers/usb/core/ledtrig-usbport.c
+++ b/drivers/usb/core/ledtrig-usbport.c
@@ -119,11 +119,6 @@ static const struct attribute_group ports_group = {
 	.attrs = ports_attrs,
 };
 
-static const struct attribute_group *ports_groups[] = {
-	&ports_group,
-	NULL
-};
-
 /***************************************
  * Adding & removing ports
  ***************************************/
@@ -307,6 +302,7 @@ static int usbport_trig_notify(struct notifier_block *nb, unsigned long action,
 static int usbport_trig_activate(struct led_classdev *led_cdev)
 {
 	struct usbport_trig_data *usbport_data;
+	int err;
 
 	usbport_data = kzalloc(sizeof(*usbport_data), GFP_KERNEL);
 	if (!usbport_data)
@@ -315,6 +311,9 @@ static int usbport_trig_activate(struct led_classdev *led_cdev)
 
 	/* List of ports */
 	INIT_LIST_HEAD(&usbport_data->ports);
+	err = sysfs_create_group(&led_cdev->dev->kobj, &ports_group);
+	if (err)
+		goto err_free;
 	usb_for_each_dev(usbport_data, usbport_trig_add_usb_dev_ports);
 	usbport_trig_update_count(usbport_data);
 
@@ -322,8 +321,11 @@ static int usbport_trig_activate(struct led_classdev *led_cdev)
 	usbport_data->nb.notifier_call = usbport_trig_notify;
 	led_set_trigger_data(led_cdev, usbport_data);
 	usb_register_notify(&usbport_data->nb);
-
 	return 0;
+
+err_free:
+	kfree(usbport_data);
+	return err;
 }
 
 static void usbport_trig_deactivate(struct led_classdev *led_cdev)
@@ -335,6 +337,8 @@ static void usbport_trig_deactivate(struct led_classdev *led_cdev)
 		usbport_trig_remove_port(usbport_data, port);
 	}
 
+	sysfs_remove_group(&led_cdev->dev->kobj, &ports_group);
+
 	usb_unregister_notify(&usbport_data->nb);
 
 	kfree(usbport_data);
@@ -344,7 +348,6 @@ static struct led_trigger usbport_led_trigger = {
 	.name     = "usbport",
 	.activate = usbport_trig_activate,
 	.deactivate = usbport_trig_deactivate,
-	.groups = ports_groups,
 };
 
 static int __init usbport_trig_init(void)