fel_lib: fix wrong const annotation

The aw_usb_read() function is meant to *fill* the buffer given to it, so
marking the pointer as "const" in the parameters list is wrong.
Some compilers (for instance GCC 11) spot this and issue a warning:
----------------------------------
fel_lib.c: In function ‘aw_read_fel_status’:
fel_lib.c:190:9: warning: ‘buf’ may be used uninitialized [-Wmaybe-uninitialize]
  190 |         aw_usb_read(dev, buf, sizeof(buf));
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fel_lib.c:168:13: note: by argument 2 of type ‘const void *’ to ‘aw_usb_read’ declared here
  168 | static void aw_usb_read(feldev_handle *dev, const void *data, size_t len)
      |             ^~~~~~~~~~~
fel_lib.c:189:14: note: ‘buf’ declared here
  189 |         char buf[8];
      |              ^~~
----------------------------------

Drop the 'const' specifier, and use the right USB bulk transfer wrapper
to make this work. The usb_bulk_send() function just happened to work
before because the actual libusb bulk transfer function is bidirectional.

Signed-off-by: Andre Przywara <osp@andrep.de>

1 files changed, 2 insertions, 3 deletions

diff --git a/fel_lib.c b/fel_lib.c
index 0852cc8..485df2b 100644
--- a/fel_lib.c
+++ b/fel_lib.c
@@ -165,11 +165,10 @@ static void aw_usb_write(feldev_handle *dev, const void *data, size_t len,
 	aw_read_usb_response(dev);
 }
 
-static void aw_usb_read(feldev_handle *dev, const void *data, size_t len)
+static void aw_usb_read(feldev_handle *dev, void *data, size_t len)
 {
 	aw_send_usb_request(dev, AW_USB_READ, len);
-	usb_bulk_send(dev->usb->handle, dev->usb->endpoint_in,
-		      data, len, false);
+	usb_bulk_recv(dev->usb->handle, dev->usb->endpoint_in, data, len);
 	aw_read_usb_response(dev);
 }