The ctl function handles a driver-specific
devctl()
command.
The prototype for this function is:
int ctl(
void *hdl,
int cmd,
void *msg,
int msglen,
int *nbytes,
int *info );
The arguments are:
- hdl
- The handle returned by the init function.
- cmd
- The device command.
- msg
- A pointer to the message buffer.
The function can change the contents of the buffer.
- msglen
- The length of the message buffer, in bytes.
- nbytes
- The number of bytes being returned.
This must not be greater than msglen.
- info
- A pointer to a location where the function can store extra status
information returned by devctl().
The function must return:
- EOK
- Success.
- Any other errno value
- Failure.