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authorMichal Sojka <sojka@merica.cz>2014-09-25 00:43:21 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-09-25 19:05:12 +0400
commit0cfbd328d60f85b0dcf66df61a3615e9a8e5d4e4 (patch)
treebae04eca569eecee711f27fd2e1d08e6f837ebbe /drivers/usb/Kconfig
parentaa923ef1aa39473b7d1f413c73a3e1d19ebde65d (diff)
downloadlinux-0cfbd328d60f85b0dcf66df61a3615e9a8e5d4e4.tar.xz
usb: Add LED triggers for USB activity
With this patch, USB activity can be signaled by blinking a LED. There are two triggers, one for activity on USB host and one for USB gadget. Both triggers should work with all host/device controllers. Tested only with musb. Performace: I measured performance overheads on ARM Cortex-A8 (TI AM335x) running on 600 MHz. Duration of usb_led_activity(): - with no LED attached to the trigger: 2 ± 1 µs - with one GPIO LED attached to the trigger: 2 ± 1 µs or 8 ± 2 µs (two peaks in histogram) Duration of functions calling usb_led_activity() (with this patch applied and no LED attached to the trigger): - __usb_hcd_giveback_urb(): 10 - 25 µs - usb_gadget_giveback_request(): 2 - 6 µs Signed-off-by: Michal Sojka <sojka@merica.cz> Acked-by: Felipe Balbi <balbi@ti.com> Tested-by: Felipe Balbi <balbi@ti.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/Kconfig')
-rw-r--r--drivers/usb/Kconfig10
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig
index cf1b19bca306..ae481c37a208 100644
--- a/drivers/usb/Kconfig
+++ b/drivers/usb/Kconfig
@@ -149,4 +149,14 @@ source "drivers/usb/phy/Kconfig"
source "drivers/usb/gadget/Kconfig"
+config USB_LED_TRIG
+ bool "USB LED Triggers"
+ depends on LEDS_CLASS && USB_COMMON && LEDS_TRIGGERS
+ help
+ This option adds LED triggers for USB host and/or gadget activity.
+
+ Say Y here if you are working on a system with led-class supported
+ LEDs and you want to use them as activity indicators for USB host or
+ gadget.
+
endif # USB_SUPPORT