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Diffstat (limited to 'Documentation/leds/ledtrig-usbport.txt')
| -rw-r--r-- | Documentation/leds/ledtrig-usbport.txt | 41 |
1 files changed, 0 insertions, 41 deletions
diff --git a/Documentation/leds/ledtrig-usbport.txt b/Documentation/leds/ledtrig-usbport.txt deleted file mode 100644 index 69f54bfb4789..000000000000 --- a/Documentation/leds/ledtrig-usbport.txt +++ /dev/null @@ -1,41 +0,0 @@ -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 selecting USB ports that should be observed. All available ones are -listed as separated entries in a "ports" subdirectory. Selecting is handled by -echoing "1" to a chosen port. - -Please note that this trigger allows selecting multiple USB ports for 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 may have 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 sysfs attributes to the LED that are documented in: -Documentation/ABI/testing/sysfs-class-led-trigger-usbport - -Example use-case: - - echo usbport > trigger - echo 1 > ports/usb1-port1 - echo 1 > ports/usb2-port1 - cat ports/usb1-port1 - echo 0 > ports/usb1-port1 |