The last big missing thing is Documentation update (this is why I'm
sending RFC). Greg pointed out we should have some entries in
Documentation/ABI, but it seems none of triggers have it. Any idea why
is that? Do we need to change it? Or is it required for new code only?
If so, should I care about Documentation/leds/ledtrig-usbport.txt at
all in this patch?
For now I didn't update Documentation/leds/ledtrig-usbport.txt with the
new new_port and remove_port API, until I get a clue how to proceed.
---
Documentation/leds/ledtrig-usbport.txt | 49 ++++++
drivers/leds/trigger/Kconfig | 8 +
drivers/leds/trigger/Makefile | 1 +
drivers/leds/trigger/ledtrig-usbport.c | 309
+++++++++++++++++++++++++++++++++
4 files changed, 367 insertions(+)
create mode 100644 Documentation/leds/ledtrig-usbport.txt
create mode 100644 drivers/leds/trigger/ledtrig-usbport.c
diff --git a/Documentation/leds/ledtrig-usbport.txt
b/Documentation/leds/ledtrig-usbport.txt
new file mode 100644
index 0000000..fa42227
--- /dev/null
+++ b/Documentation/leds/ledtrig-usbport.txt
@@ -0,0 +1,49 @@
+USB port LED trigger
+====================
+
+This LED trigger can be used for signalling to the user a presence of
USB device
+in a given port. It simply turns on LED when device appears and turns
it off
+when it disappears.
+
+It requires specifying a list of USB ports that should be observed.
Used format
+matches Linux kernel format and consists of a root hub number and a
hub port
+separated by a dash (e.g. 3-1).
+
+It is also possible to handle devices with internal hubs (that are
always
+connected to the root hub). User can simply specify internal hub
ports then
+(e.g. 1-1.1, 1-1.2, etc.).
+
+Please note that this trigger allows assigning multiple USB ports to
a single
+LED. This can be useful in two cases:
+
+1) Device with single USB LED and few physical ports
+
+In such a case LED will be turned on as long as there is at least one
connected
+USB device.
+
+2) Device with a physical port handled by few controllers
+
+Some devices have e.g. one controller per PHY standard. E.g. USB 3.0
physical
+port may be handled by ohci-platform, ehci-platform and xhci-hcd. If
there is
+only one LED user will most likely want to assign ports from all 3 hubs.
+
+
+This trigger can be activated from user space on led class devices as
shown
+below:
+
+ echo usbport > trigger
+
+This adds the following sysfs attributes to the LED:
+
+ ports - Reading it lists all USB ports assigned to the trigger.
Writing USB
+ port number to it will make this driver start observing it.
It's also
+ possible to remove USB port from observable list by writing it
with a
+ "-" prefix.
+
+Example use-case:
+
+ echo usbport > trigger
+ echo 4-1 > ports
+ echo 2-1 > ports
+ echo -4-1 > ports
+ cat ports
diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index 3f9ddb9..bdd6fd2 100644
--- a/drivers/leds/trigger/Kconfig
+++ b/drivers/leds/trigger/Kconfig
@@ -126,4 +126,12 @@ config LEDS_TRIGGER_PANIC
a different trigger.
If unsure, say Y.
+config LEDS_TRIGGER_USBPORT
+ tristate "USB port LED trigger"
+ depends on LEDS_TRIGGERS && USB
+ help
+ This allows LEDs to be controlled by USB events. Enabling this
option
+ allows specifying list of USB ports that should turn on LED
when some
+ USB device gets connected.
+
endif # LEDS_TRIGGERS
diff --git a/drivers/leds/trigger/Makefile
b/drivers/leds/trigger/Makefile
index a72c43c..56e1741 100644
--- a/drivers/leds/trigger/Makefile
+++ b/drivers/leds/trigger/Makefile
@@ -10,3 +10,4 @@ obj-$(CONFIG_LEDS_TRIGGER_DEFAULT_ON) +=
ledtrig-default-on.o
obj-$(CONFIG_LEDS_TRIGGER_TRANSIENT) += ledtrig-transient.o
obj-$(CONFIG_LEDS_TRIGGER_CAMERA) += ledtrig-camera.o
obj-$(CONFIG_LEDS_TRIGGER_PANIC) += ledtrig-panic.o
+obj-$(CONFIG_LEDS_TRIGGER_USBPORT) += ledtrig-usbport.o
diff --git a/drivers/leds/trigger/ledtrig-usbport.c
b/drivers/leds/trigger/ledtrig-usbport.c
new file mode 100644
index 0000000..1532b60
--- /dev/null
+++ b/drivers/leds/trigger/ledtrig-usbport.c
@@ -0,0 +1,309 @@
+/*
+ * USB port LED trigger
+ *
+ * Copyright (C) 2016 Rafał Miłecki <rafal@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ */
+
+#include <linux/device.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include "../leds.h"
+
+struct usbport_trig_port {
+ char *name;
+ struct device_attribute attr;
+ struct list_head list;
+};
+
+struct usbport_trig_data {
+ struct led_classdev *led_cdev;
+ struct list_head ports;
+ struct kobject *ports_dir;
+ struct notifier_block nb;
+ int count; /* Amount of connected matching devices */
+};
+
+/*
+ * Helpers
+ */
+
+/**
+ * usbport_trig_usb_dev_observed - Check if dev is connected to
observerd port
+ */
+static bool usbport_trig_usb_dev_observed(struct usbport_trig_data
*usbport_data,
+ struct usb_device *usb_dev)
+{
+ struct usbport_trig_port *port;
+ const char *name = dev_name(&usb_dev->dev);
+
+ list_for_each_entry(port, &usbport_data->ports, list) {
+ if (!strcmp(port->name, name))
+ return true;
+ }
+
+ 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_nosleep(led_cdev,
+ usbport_data->count ? LED_FULL : LED_OFF);
+}
+
+static int usbport_trig_add_port(struct usbport_trig_data *usbport_data,
+ const char *name)
+{
+ struct usbport_trig_port *port;
+ int err;
+
+ port = kzalloc(sizeof(*port), GFP_KERNEL);
+ if (!port) {
+ err = -ENOMEM;
+ goto err_out;
+ }
+
+ port->name = kzalloc(strlen(name) + 1, GFP_KERNEL);
+ if (!port->name) {
+ err = -ENOMEM;
+ goto err_free_port;
+ }
+ strcpy(port->name, name);
+
+ port->attr.attr.name = port->name;
+
+ err = sysfs_create_file(usbport_data->ports_dir, &port->attr.attr);
+ if (err)
+ goto err_free_name;
+
+ list_add_tail(&port->list, &usbport_data->ports);
+
+ return 0;
+
+err_free_name:
+ kfree(port->name);
+err_free_port:
+ kfree(port);
+err_out:
+ return err;
+}
+
+static void usbport_trig_remove_port(struct usbport_trig_data
*usbport_data,
+ struct usbport_trig_port *port)
+{
+ list_del(&port->list);
+ sysfs_remove_file(usbport_data->ports_dir, &port->attr.attr);
+ kfree(port->name);
+ kfree(port);
+}
+
+/*
+ * Device attr
+ */
+
+static ssize_t new_port_store(struct device *dev, struct
device_attribute *attr,
+ const char *buf, size_t size)
+{
+ struct led_classdev *led_cdev = dev_get_drvdata(dev);
+ struct usbport_trig_data *usbport_data = led_cdev->trigger_data;
+ struct usbport_trig_port *port;
+ char *name;
+ size_t len;
+
+ len = strlen(buf);
+ /* For user convenience trim line break */
+ if (len && buf[len - 1] == '\n')
+ len--;
+ if (!len)
+ return -EINVAL;
+
+ name = kzalloc(len + 1, GFP_KERNEL);
+ if (!name)
+ return -ENOMEM;
+ strncpy(name, buf, len);
+
+ list_for_each_entry(port, &usbport_data->ports, list) {
+ if (!strcmp(port->name, name))
+ return -EEXIST;
+ }
+
+ usbport_trig_add_port(usbport_data, name);
+
+ kfree(name);
+
+ usbport_trig_update_count(usbport_data);
+
+ return size;
+}
+
+static DEVICE_ATTR(new_port, S_IWUSR, NULL, new_port_store);
+
+static ssize_t remove_port_store(struct device *dev,
+ struct device_attribute *attr, const char *buf,
+ size_t size)
+{
+ struct led_classdev *led_cdev = dev_get_drvdata(dev);
+ struct usbport_trig_data *usbport_data = led_cdev->trigger_data;
+ struct usbport_trig_port *port, *tmp;
+ size_t len;
+
+ len = strlen(buf);
+ /* For user convenience trim line break */
+ if (len && buf[len - 1] == '\n')
+ len--;
+ if (!len)
+ return -EINVAL;
+
+ list_for_each_entry_safe(port, tmp, &usbport_data->ports,
+ list) {
+ if (strlen(port->name) == len &&
+ !strncmp(port->name, buf, len)) {
+ usbport_trig_remove_port(usbport_data, port);
+ usbport_trig_update_count(usbport_data);
+ return size;
+ }
+ }
+
+ return -ENOENT;
+}
+
+static DEVICE_ATTR(remove_port, S_IWUSR, NULL, remove_port_store);
+
+/*
+ * 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;
+
+ if (!usbport_trig_usb_dev_observed(usbport_data, data))
+ return NOTIFY_DONE;
+
+ switch (action) {
+ case USB_DEVICE_ADD:
+ if (usbport_data->count++ == 0)
+ led_set_brightness_nosleep(led_cdev, LED_FULL);
+ return NOTIFY_OK;
+ case USB_DEVICE_REMOVE:
+ if (--usbport_data->count == 0)
+ led_set_brightness_nosleep(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;
+
+ /* Storing ports */
+ INIT_LIST_HEAD(&usbport_data->ports);
+ usbport_data->ports_dir = kobject_create_and_add("ports",
+ &led_cdev->dev->kobj);
+ if (!usbport_data->ports_dir)
+ goto err_free;
+
+ /* API for ports management */
+ err = device_create_file(led_cdev->dev, &dev_attr_new_port);
+ if (err)
+ goto err_put_ports;
+ err = device_create_file(led_cdev->dev, &dev_attr_remove_port);
+ if (err)
+ goto err_remove_new_port;
+
+ /* 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_remove_new_port:
+ device_remove_file(led_cdev->dev, &dev_attr_new_port);
+err_put_ports:
+ kobject_put(usbport_data->ports_dir);
+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);
+
+ device_remove_file(led_cdev->dev, &dev_attr_remove_port);
+ device_remove_file(led_cdev->dev, &dev_attr_new_port);
+
+ kobject_put(usbport_data->ports_dir);
+
+ 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@xxxxxxxxxx>");
+MODULE_DESCRIPTION("USB port trigger");
+MODULE_LICENSE("GPL");
