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author | Michal Sojka <sojka@merica.cz> | 2014-09-24 20:43:21 (GMT) |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-09-25 15:05:12 (GMT) |
commit | 0cfbd328d60f85b0dcf66df61a3615e9a8e5d4e4 (patch) | |
tree | bae04eca569eecee711f27fd2e1d08e6f837ebbe /drivers/usb/gadget | |
parent | aa923ef1aa39473b7d1f413c73a3e1d19ebde65d (diff) | |
download | linux-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/gadget')
-rw-r--r-- | drivers/usb/gadget/udc/udc-core.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/usb/gadget/udc/udc-core.c b/drivers/usb/gadget/udc/udc-core.c index 16d3f6f..f107bb6 100644 --- a/drivers/usb/gadget/udc/udc-core.c +++ b/drivers/usb/gadget/udc/udc-core.c @@ -27,6 +27,7 @@ #include <linux/usb/ch9.h> #include <linux/usb/gadget.h> +#include <linux/usb.h> /** * struct usb_udc - describes one usb device controller @@ -116,6 +117,9 @@ EXPORT_SYMBOL_GPL(usb_gadget_unmap_request); void usb_gadget_giveback_request(struct usb_ep *ep, struct usb_request *req) { + if (likely(req->status == 0)) + usb_led_activity(USB_LED_EVENT_GADGET); + req->complete(ep, req); } EXPORT_SYMBOL_GPL(usb_gadget_giveback_request); |