staging: gpib: Fix erroneous removal of blank before newline

The USB_GPIB_SET_LINES command string used to be: "\nIBDC \n" but when
we were merging this code into the upstream kernel we deleted the space
character before the newline to make checkpatch happy.  That turned
out to be a mistake.

The "\nIBDC" part of the string is a command that we pass to the
firmware and the next character is a variable u8 value.
It gets set in set_control_line().

 msg[leng - 2] = value ? (retval & ~line) : retval | line;

where leng is the length of the command string.

Imagine the parameter was supposed to be "8".
With the pre-merge code the command string would be "\nIBDC8\n"
With the post-merge code the command string became "\nIBD8\n"

The firmware doesn't recognize "IBD8" as a valid command and rejects it.

Putting a "." where the parameter is supposed to go fixes the driver
and makes checkpatch happy.  Same thing with the other define and
the in-line assignment.

Reported-by: Marcello Carla' <marcello.carla@gmx.com>
Fixes: fce79512a96a ("staging: gpib: Add LPVO DIY USB GPIB driver")
Co-developed-by: Marcello Carla' <marcello.carla@gmx.com>
Signed-off-by: Marcello Carla' <marcello.carla@gmx.com>
Signed-off-by: Dave Penkler <dpenkler@gmail.com>
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/20241205093442.5796-1-dpenkler@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/gpib/lpvo_usb_gpib/lpvo_usb_gpib.c b/drivers/staging/gpib/lpvo_usb_gpib/lpvo_usb_gpib.c
index 267651a15fa00e8925c4d08a95e2f61206e76a61..2de0b470c7bcbb10c78266e8f46a694dfd78a735 100644 (file)
--- a/drivers/staging/gpib/lpvo_usb_gpib/lpvo_usb_gpib.c
+++ b/drivers/staging/gpib/lpvo_usb_gpib/lpvo_usb_gpib.c
@@ -99,8 +99,8 @@ module_param(debug, int, 0644);
 #define USB_GPIB_DEBUG_ON    "\nIBDE\xAA\n"
 #define USB_GPIB_SET_LISTEN  "\nIBDT0\n"
 #define USB_GPIB_SET_TALK    "\nIBDT1\n"
-#define USB_GPIB_SET_LINES   "\nIBDC\n"
-#define USB_GPIB_SET_DATA    "\nIBDM\n"
+#define USB_GPIB_SET_LINES   "\nIBDC.\n"
+#define USB_GPIB_SET_DATA    "\nIBDM.\n"
 #define USB_GPIB_READ_LINES  "\nIBD?C\n"
 #define USB_GPIB_READ_DATA   "\nIBD?M\n"
 #define USB_GPIB_READ_BUS    "\nIBD??\n"
@@ -589,7 +589,7 @@ static int usb_gpib_command(gpib_board_t *board,
                            size_t *bytes_written)
 {
        int i, retval;
-       char command[6] = "IBc\n";
+       char command[6] = "IBc.\n";
 
        DIA_LOG(1, "enter %p\n", board);