usb-linux: add some explanatory comments to usb-linux.c

1 files changed, 5 insertions, 0 deletions

diff --git a/src/usb-linux.c b/src/usb-linux.c
index 127446a..94db8f2 100644
--- a/src/usb-linux.c
+++ b/src/usb-linux.c
@@ -93,6 +93,7 @@ static void usb_disconnect(struct usb_device *dev)
         free(dev);
 }
 
+// Callback from write operation
 static void tx_callback(struct libusb_transfer *xfer)
 {
         struct usb_device *dev = xfer->user_data;
@@ -162,6 +163,9 @@ int usb_send(struct usb_device *dev, const unsigned char *buf, int length)
         return 0;
 }
 
+// Callback from read operation
+// Under normal operation this issues a new read transfer request immediately,
+// doing a kind of read-callback loop
 static void rx_callback(struct libusb_transfer *xfer)
 {
         struct usb_device *dev = xfer->user_data;
@@ -206,6 +210,7 @@ static void rx_callback(struct libusb_transfer *xfer)
         }
 }
 
+// Start a read-callback loop for this device
 static int start_rx(struct usb_device *dev)
 {
         int res;