This commit adds a new trigger that can turn on LED when USB device gets
connected to the USB port. This can be useful for various home routers
that have USB port and a proper LED telling user a device is connected.
Right now this trigger is usable with a proper DT only, there isn't a
way to specify USB ports from user space. This may change in a future.
Signed-off-by: Rafał Miłecki <zajec5@xxxxxxxxx>
---
V2: The first version got support for specifying list of USB ports from
user space only. There was a (big try &) discussion on adding DT
support. It led to a pretty simple solution of comparing of_node of
usb_device to of_node specified in usb-ports property.
Since it appeared DT support may be simpler and non-DT a bit more
complex, this version drops previous support for "ports" and
"new_port" and focuses on DT only. The plan is to see if this
solution with DT is OK, get it accepted and then work on non-DT.
Felipe: if there won't be any objections I'd like to ask for your Ack.
---
Documentation/devicetree/bindings/leds/common.txt | 11 ++
Documentation/leds/ledtrig-usbport.txt | 19 ++
drivers/leds/trigger/Kconfig | 8 +
drivers/leds/trigger/Makefile | 1 +
drivers/leds/trigger/ledtrig-usbport.c | 206 ++++++++++++++++++++++
5 files changed, 245 insertions(+)
create mode 100644 Documentation/leds/ledtrig-usbport.txt
create mode 100644 drivers/leds/trigger/ledtrig-usbport.c
diff --git a/Documentation/devicetree/bindings/leds/common.txt b/Documentation/devicetree/bindings/leds/common.txt
index af10678..75536f7 100644
--- a/Documentation/devicetree/bindings/leds/common.txt
+++ b/Documentation/devicetree/bindings/leds/common.txt
@@ -50,6 +50,12 @@ property can be omitted.
For controllers that have no configurable timeout the flash-max-timeout-us
property can be omitted.
+Trigger specific properties for child nodes:
+
+usbport trigger:
+- usb-ports : List of USB ports that usbport should observed for turning on a
+ given LED.
+
Examples:
system-status {
@@ -58,6 +64,11 @@ system-status {
...
};
+usb {
+ label = "USB";
+ usb-ports = <&ohci_port1>, <&ehci_port1>;
+};
+
camera-flash {
label = "Flash";
led-sources = <0>, <1>;
diff --git a/Documentation/leds/ledtrig-usbport.txt b/Documentation/leds/ledtrig-usbport.txt
new file mode 100644
index 0000000..642c4cd
--- /dev/null
+++ b/Documentation/leds/ledtrig-usbport.txt
@@ -0,0 +1,19 @@
+USB port LED trigger
+====================
+
+This LED trigger can be used for signaling 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. This can be
+done in DT by setting a proper property with list of a phandles. If more than
+one port is specified, LED will be turned on as along as there is at least one
+device connected to any of ports.
+
+This trigger can be activated from user space on led class devices as shown
+below:
+
+ echo usbport > trigger
+
+Nevertheless, current there isn't a way to specify list of USB ports from user
+space.
diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index 9893d91..5b8e7c7 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 && OF
+ help
+ This allows LEDs to be controlled by USB events. This trigger will
+ enable LED if some USB device gets connected to any of ports specified
+ in DT.
+
endif # LEDS_TRIGGERS
diff --git a/drivers/leds/trigger/Makefile b/drivers/leds/trigger/Makefile
index 8cc64a4..80e2494 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..97b064c
--- /dev/null
+++ b/drivers/leds/trigger/ledtrig-usbport.c
@@ -0,0 +1,206 @@
+/*
+ * USB port LED trigger
+ *
+ * Copyright (C) 2016 Rafał Miłecki <rafal.milecki@xxxxxxxxx>
+ *
+ * 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/of.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include "../leds.h"
+
+struct usbport_trig_port {
+ struct device_node *np;
+ struct list_head list;
+};
+
+struct usbport_trig_data {
+ struct led_classdev *led_cdev;
+ struct list_head ports;
+ struct notifier_block nb;
+ int count; /* Amount of connected matching devices */
+};
+
+static int usbport_trig_check_usb_dev(struct usb_device *usb_dev, void *data)
+{
+ struct usbport_trig_data *usbport_data = data;
+ struct device_node *np = usb_dev->dev.of_node;
+ struct usbport_trig_port *port;
+
+ list_for_each_entry(port, &usbport_data->ports, list) {
+ if (port->np == np) {
+ usbport_data->count++;
+ break;
+ }
+ }
+
+ return 0;
+}
+
+static int usbport_trig_get_ports(struct usbport_trig_data *usbport_data)
+{
+ struct led_classdev *led_cdev = usbport_data->led_cdev;
+ struct device *dev = led_cdev->dev;
+ struct device_node *np = dev->of_node;
+ struct of_phandle_args args;
+ struct usbport_trig_port *port;
+ int count, i;
+
+ if (!np)
+ return -ENOENT;
+
+ count = of_count_phandle_with_args(np, "usb-ports", NULL);
+ if (count < 0) {
+ dev_warn(dev, "Failed to get USB ports for %s\n",
+ np->full_name);
+ return count;
+ }
+
+ if (!count) {
+ dev_warn(dev, "There aren't USB ports assigned to the %s\n",
+ np->full_name);
+ return -ENOENT;
+ }
+
+ for (i = 0; i < count; i++) {
+ int err;
+
+ err = of_parse_phandle_with_args(np, "usb-ports", NULL, i,
+ &args);
+ if (err) {
+ dev_err(dev, "Failed to get USB port phandle at index %d: %d\n",
+ i, err);
+ continue;
+ }
+
+ port = kzalloc(sizeof(*port), GFP_KERNEL);
+ if (port) {
+ port->np = args.np;
+ list_add_tail(&port->list, &usbport_data->ports);
+ }
+
+ of_node_put(args.np);
+ }
+
+ usb_for_each_dev(usbport_data, usbport_trig_check_usb_dev);
+ if (usbport_data->count)
+ led_set_brightness_nosleep(led_cdev, LED_FULL);
+
+ list_for_each_entry(port, &usbport_data->ports, list) {
+ dev_dbg(dev, "Added USB port %s\n", port->np->full_name);
+ }
+
+ return 0;
+}
+
+static bool usbport_trig_match(struct usbport_trig_data *usbport_data,
+ struct usb_device *usb_dev)
+{
+ struct device_node *np = usb_dev->dev.of_node;
+ struct usbport_trig_port *port;
+
+ if (!np)
+ return false;
+
+ list_for_each_entry(port, &usbport_data->ports, list) {
+ if (port->np == np)
+ return true;
+ }
+
+ return false;
+}
+
+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;
+
+ switch (action) {
+ case USB_DEVICE_ADD:
+ if (usbport_trig_match(usbport_data, data)) {
+ if (usbport_data->count++ == 0)
+ led_set_brightness_nosleep(led_cdev, LED_FULL);
+ }
+ break;
+ case USB_DEVICE_REMOVE:
+ if (usbport_trig_match(usbport_data, data)) {
+ if (--usbport_data->count == 0)
+ led_set_brightness_nosleep(led_cdev, LED_OFF);
+ }
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+static void usbport_trig_activate(struct led_classdev *led_cdev)
+{
+ struct usbport_trig_data *usbport_data;
+
+ usbport_data = kzalloc(sizeof(*usbport_data), GFP_KERNEL);
+ if (!usbport_data)
+ return;
+ led_cdev->trigger_data = usbport_data;
+
+ usbport_data->led_cdev = led_cdev;
+
+ INIT_LIST_HEAD(&usbport_data->ports);
+ usbport_trig_get_ports(usbport_data);
+
+ usbport_data->nb.notifier_call = usbport_trig_notify,
+ usb_register_notify(&usbport_data->nb);
+
+ led_cdev->activated = true;
+}
+
+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;
+
+ usb_unregister_notify(&usbport_data->nb);
+
+ list_for_each_entry_safe(port, tmp, &usbport_data->ports, list) {
+ list_del(&port->list);
+ kfree(port);
+ }
+
+ 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@xxxxxxxxx>");
+MODULE_DESCRIPTION("USB port trigger");
+MODULE_LICENSE("GPL");
--
1.8.4.5
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