| The uleds driver supports userspace LEDs. This can be useful for testing |
| triggers and can also be used to implement virtual LEDs. |
| When the driver is loaded, a character device is created at /dev/uleds. To |
| create a new LED class device, open /dev/uleds and write a uleds_user_dev |
| structure to it (found in kernel public header file linux/uleds.h). |
| #define LED_MAX_NAME_SIZE 64 |
| char name[LED_MAX_NAME_SIZE]; |
| A new LED class device will be created with the name given. The name can be |
| any valid sysfs device node name, but consider using the LED class naming |
| convention of "devicename:color:function". |
| The current brightness is found by reading a single byte from the character |
| device. Values are unsigned: 0 to 255. Reading will block until the brightness |
| changes. The device node can also be polled to notify when the brightness value |
| The LED class device will be removed when the open file handle to /dev/uleds |
| Multiple LED class devices are created by opening additional file handles to |
| See tools/leds/uledmon.c for an example userspace program. |