--- /dev/null
+/*
+ * USB port LED trigger
+ *
+ * Copyright (C) 2016 Rafał Miłecki <rafal@milecki.pl>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/device.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/usb.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_cdev->brightness_set(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
+ ***************************************/
+
+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;
+
+ 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);
+
+ 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_cdev->brightness_set(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_cdev->brightness_set(led_cdev, LED_OFF);
+ return NOTIFY_OK;
+ }
+
+ return NOTIFY_DONE;
+}
+
+static void 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;
+ 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);
+
+ /* Notifications */
+ usbport_data->nb.notifier_call = usbport_trig_notify,
+ led_cdev->trigger_data = usbport_data;
+ usb_register_notify(&usbport_data->nb);
+
+ led_cdev->activated = true;
+ return;
+
+err_free:
+ kfree(usbport_data);
+}
+
+static void usbport_trig_deactivate(struct led_classdev *led_cdev)
+{
+ struct usbport_trig_data *usbport_data = led_cdev->trigger_data;
+ struct usbport_trig_port *port, *tmp;
+
+ if (!led_cdev->activated)
+ return;
+
+ list_for_each_entry_safe(port, tmp, &usbport_data->ports, list) {
+ usbport_trig_remove_port(usbport_data, port);
+ }
+
+ usb_unregister_notify(&usbport_data->nb);
+
+ sysfs_remove_group(&led_cdev->dev->kobj, &ports_group);
+
+ kfree(usbport_data);
+
+ led_cdev->activated = false;
+}
+
+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");
projects / users / hch / misc.git / commitdiff