linux-stable/drivers/usb/core/ledtrig-usbport.c
Christian Lamparter 91f7d2e898 USB: leds: fix regression in usbport led trigger
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: 6f7b0bad88 ("usb: simplify usbport trigger")
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Cc: stable <stable@vger.kernel.org>
Acked-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-18 09:55:05 +01:00

368 lines
8.8 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* USB port LED trigger
*
* Copyright (C) 2016 Rafał Miłecki <rafal@milecki.pl>
*/
#include <linux/device.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/usb/of.h>
struct usbport_trig_data {
struct led_classdev *led_cdev;
struct list_head ports;
struct notifier_block nb;
int count; /* Amount of connected matching devices */
};
struct usbport_trig_port {
struct usbport_trig_data *data;
struct usb_device *hub;
int portnum;
char *port_name;
bool observed;
struct device_attribute attr;
struct list_head list;
};
/***************************************
* Helpers
***************************************/
/**
* usbport_trig_usb_dev_observed - Check if dev is connected to observed port
*/
static bool usbport_trig_usb_dev_observed(struct usbport_trig_data *usbport_data,
struct usb_device *usb_dev)
{
struct usbport_trig_port *port;
if (!usb_dev->parent)
return false;
list_for_each_entry(port, &usbport_data->ports, list) {
if (usb_dev->parent == port->hub &&
usb_dev->portnum == port->portnum)
return port->observed;
}
return false;
}
static int usbport_trig_usb_dev_check(struct usb_device *usb_dev, void *data)
{
struct usbport_trig_data *usbport_data = data;
if (usbport_trig_usb_dev_observed(usbport_data, usb_dev))
usbport_data->count++;
return 0;
}
/**
* usbport_trig_update_count - Recalculate amount of connected matching devices
*/
static void usbport_trig_update_count(struct usbport_trig_data *usbport_data)
{
struct led_classdev *led_cdev = usbport_data->led_cdev;
usbport_data->count = 0;
usb_for_each_dev(usbport_data, usbport_trig_usb_dev_check);
led_set_brightness(led_cdev, usbport_data->count ? LED_FULL : LED_OFF);
}
/***************************************
* Device attr
***************************************/
static ssize_t usbport_trig_port_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct usbport_trig_port *port = container_of(attr,
struct usbport_trig_port,
attr);
return sprintf(buf, "%d\n", port->observed) + 1;
}
static ssize_t usbport_trig_port_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t size)
{
struct usbport_trig_port *port = container_of(attr,
struct usbport_trig_port,
attr);
if (!strcmp(buf, "0") || !strcmp(buf, "0\n"))
port->observed = 0;
else if (!strcmp(buf, "1") || !strcmp(buf, "1\n"))
port->observed = 1;
else
return -EINVAL;
usbport_trig_update_count(port->data);
return size;
}
static struct attribute *ports_attrs[] = {
NULL,
};
static const struct attribute_group ports_group = {
.name = "ports",
.attrs = ports_attrs,
};
/***************************************
* Adding & removing ports
***************************************/
/**
* usbport_trig_port_observed - Check if port should be observed
*/
static bool usbport_trig_port_observed(struct usbport_trig_data *usbport_data,
struct usb_device *usb_dev, int port1)
{
struct device *dev = usbport_data->led_cdev->dev;
struct device_node *led_np = dev->of_node;
struct of_phandle_args args;
struct device_node *port_np;
int count, i;
if (!led_np)
return false;
/*
* Get node of port being added
*
* FIXME: This is really the device node of the connected device
*/
port_np = usb_of_get_device_node(usb_dev, port1);
if (!port_np)
return false;
of_node_put(port_np);
/* Amount of trigger sources for this LED */
count = of_count_phandle_with_args(led_np, "trigger-sources",
"#trigger-source-cells");
if (count < 0) {
dev_warn(dev, "Failed to get trigger sources for %pOF\n",
led_np);
return false;
}
/* Check list of sources for this specific port */
for (i = 0; i < count; i++) {
int err;
err = of_parse_phandle_with_args(led_np, "trigger-sources",
"#trigger-source-cells", i,
&args);
if (err) {
dev_err(dev, "Failed to get trigger source phandle at index %d: %d\n",
i, err);
continue;
}
of_node_put(args.np);
if (args.np == port_np)
return true;
}
return false;
}
static int usbport_trig_add_port(struct usbport_trig_data *usbport_data,
struct usb_device *usb_dev,
const char *hub_name, int portnum)
{
struct led_classdev *led_cdev = usbport_data->led_cdev;
struct usbport_trig_port *port;
size_t len;
int err;
port = kzalloc(sizeof(*port), GFP_KERNEL);
if (!port) {
err = -ENOMEM;
goto err_out;
}
port->data = usbport_data;
port->hub = usb_dev;
port->portnum = portnum;
port->observed = usbport_trig_port_observed(usbport_data, usb_dev,
portnum);
len = strlen(hub_name) + 8;
port->port_name = kzalloc(len, GFP_KERNEL);
if (!port->port_name) {
err = -ENOMEM;
goto err_free_port;
}
snprintf(port->port_name, len, "%s-port%d", hub_name, portnum);
sysfs_attr_init(&port->attr.attr);
port->attr.attr.name = port->port_name;
port->attr.attr.mode = S_IRUSR | S_IWUSR;
port->attr.show = usbport_trig_port_show;
port->attr.store = usbport_trig_port_store;
err = sysfs_add_file_to_group(&led_cdev->dev->kobj, &port->attr.attr,
ports_group.name);
if (err)
goto err_free_port_name;
list_add_tail(&port->list, &usbport_data->ports);
return 0;
err_free_port_name:
kfree(port->port_name);
err_free_port:
kfree(port);
err_out:
return err;
}
static int usbport_trig_add_usb_dev_ports(struct usb_device *usb_dev,
void *data)
{
struct usbport_trig_data *usbport_data = data;
int i;
for (i = 1; i <= usb_dev->maxchild; i++)
usbport_trig_add_port(usbport_data, usb_dev,
dev_name(&usb_dev->dev), i);
return 0;
}
static void usbport_trig_remove_port(struct usbport_trig_data *usbport_data,
struct usbport_trig_port *port)
{
struct led_classdev *led_cdev = usbport_data->led_cdev;
list_del(&port->list);
sysfs_remove_file_from_group(&led_cdev->dev->kobj, &port->attr.attr,
ports_group.name);
kfree(port->port_name);
kfree(port);
}
static void usbport_trig_remove_usb_dev_ports(struct usbport_trig_data *usbport_data,
struct usb_device *usb_dev)
{
struct usbport_trig_port *port, *tmp;
list_for_each_entry_safe(port, tmp, &usbport_data->ports, list) {
if (port->hub == usb_dev)
usbport_trig_remove_port(usbport_data, port);
}
}
/***************************************
* Init, exit, etc.
***************************************/
static int usbport_trig_notify(struct notifier_block *nb, unsigned long action,
void *data)
{
struct usbport_trig_data *usbport_data =
container_of(nb, struct usbport_trig_data, nb);
struct led_classdev *led_cdev = usbport_data->led_cdev;
struct usb_device *usb_dev = data;
bool observed;
observed = usbport_trig_usb_dev_observed(usbport_data, usb_dev);
switch (action) {
case USB_DEVICE_ADD:
usbport_trig_add_usb_dev_ports(usb_dev, usbport_data);
if (observed && usbport_data->count++ == 0)
led_set_brightness(led_cdev, LED_FULL);
return NOTIFY_OK;
case USB_DEVICE_REMOVE:
usbport_trig_remove_usb_dev_ports(usbport_data, usb_dev);
if (observed && --usbport_data->count == 0)
led_set_brightness(led_cdev, LED_OFF);
return NOTIFY_OK;
}
return NOTIFY_DONE;
}
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)
return -ENOMEM;
usbport_data->led_cdev = 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);
/* Notifications */
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)
{
struct usbport_trig_data *usbport_data = led_get_trigger_data(led_cdev);
struct usbport_trig_port *port, *tmp;
list_for_each_entry_safe(port, tmp, &usbport_data->ports, list) {
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);
}
static struct led_trigger usbport_led_trigger = {
.name = "usbport",
.activate = usbport_trig_activate,
.deactivate = usbport_trig_deactivate,
};
static int __init usbport_trig_init(void)
{
return led_trigger_register(&usbport_led_trigger);
}
static void __exit usbport_trig_exit(void)
{
led_trigger_unregister(&usbport_led_trigger);
}
module_init(usbport_trig_init);
module_exit(usbport_trig_exit);
MODULE_AUTHOR("Rafał Miłecki <rafal@milecki.pl>");
MODULE_DESCRIPTION("USB port trigger");
MODULE_LICENSE("GPL v2");