unknown symbol in module

[jschoch]

not sure how to trouble shoot this.

pi@lchr:~/linux $ make kernelversion
4.9.13

pi@lchr:~/linux $ uname -a
Linux lchr 4.9.13-v7+ #974 SMP Wed Mar 1 20:09:48 GMT 2017 armv7l GNU/Linux

pi@lchr:~/driver/CH341SER_LINUX $ make
make -C /lib/modules/4.9.13-v7+/build  M=/home/pi/driver/CH341SER_LINUX
make[1]: Entering directory '/home/pi/linux-5d1da107bc619c1cc091ee5301f85cd89a6d92fb'
  LD      /home/pi/driver/CH341SER_LINUX/built-in.o
  CC [M]  /home/pi/driver/CH341SER_LINUX/ch34x.o
/home/pi/driver/CH341SER_LINUX/ch34x.c: In function âch34x_closeâ:
/home/pi/driver/CH341SER_LINUX/ch34x.c:566:15: warning: unused variable âwaitâ [-Wunused-variable]
  wait_queue_t wait;
               ^
/home/pi/driver/CH341SER_LINUX/ch34x.c:565:7: warning: unused variable âtimeoutâ [-Wunused-variable]
  long timeout;
       ^
/home/pi/driver/CH341SER_LINUX/ch34x.c:564:6: warning: unused variable âbpsâ [-Wunused-variable]
  int bps;
      ^
  Building modules, stage 2.
  MODPOST 1 modules
  CC      /home/pi/driver/CH341SER_LINUX/ch34x.mod.o
  LD [M]  /home/pi/driver/CH341SER_LINUX/ch34x.ko
make[1]: Leaving directory '/home/pi/linux-5d1da107bc619c1cc091ee5301f85cd89a6d92fb'


pi@lchr:~/driver/CH341SER_LINUX $ sudo insmod ch34x.ko
insmod: ERROR: could not insert module ch34x.ko: Unknown symbol in module