diff options
Diffstat (limited to 'drivers/usb/common/debug.c')
| -rw-r--r-- | drivers/usb/common/debug.c | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/drivers/usb/common/debug.c b/drivers/usb/common/debug.c index ba849c7bc5c7..a76a086b9c54 100644 --- a/drivers/usb/common/debug.c +++ b/drivers/usb/common/debug.c @@ -207,8 +207,26 @@ static void usb_decode_set_isoch_delay(__u8 wValue, char *str, size_t size) snprintf(str, size, "Set Isochronous Delay(Delay = %d ns)", wValue); } -/* - * usb_decode_ctrl - returns a string representation of ctrl request +/** + * usb_decode_ctrl - Returns human readable representation of control request. + * @str: buffer to return a human-readable representation of control request. + * This buffer should have about 200 bytes. + * @size: size of str buffer. + * @bRequestType: matches the USB bmRequestType field + * @bRequest: matches the USB bRequest field + * @wValue: matches the USB wValue field (CPU byte order) + * @wIndex: matches the USB wIndex field (CPU byte order) + * @wLength: matches the USB wLength field (CPU byte order) + * + * Function returns decoded, formatted and human-readable description of + * control request packet. + * + * The usage scenario for this is for tracepoints, so function as a return + * use the same value as in parameters. This approach allows to use this + * function in TP_printk + * + * Important: wValue, wIndex, wLength parameters before invoking this function + * should be processed by le16_to_cpu macro. */ const char *usb_decode_ctrl(char *str, size_t size, __u8 bRequestType, __u8 bRequest, __u16 wValue, __u16 wIndex, |