drivers/usb/core/ledtrig-usbport.c

Source file repositories/reference/linux-study-clean/drivers/usb/core/ledtrig-usbport.c

File Facts

System
Linux kernel
Corpus path
drivers/usb/core/ledtrig-usbport.c
Extension
.c
Size
8814 bytes
Lines
359
Domain
Driver Families
Bucket
drivers/usb
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

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 sysfs_emit(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

Annotation

Implementation Notes