parport_wait_peripheral - wait for status lines to change in 35ms
2. SYNOPSIS ▲
int parport_wait_peripheral(struct parport * port , unsigned char mask , unsigned char result );
3. ARGUMENTS ▲
port to watch
status lines to watch
desired values of chosen status lines
4. DESCRIPTION ▲
This function waits until the masked status lines have the desired values, or until 35ms have elapsed (see IEEE 1284-1994 page 24 to 25 for why this value in particular is hardcoded). The mask and result parameters are bitmasks, with the bits defined by the constants in parport.h: PARPORT_STATUS_BUSY, and so on.
The port is polled quickly to start off with, in anticipation of a fast response from the peripheral. This fast polling time is configurable (using /proc), and defaults to 500usec. If the timeout for this port (see parport_set_timeout) is zero, the fast polling time is 35ms, and this function does not call schedule.
If the timeout for this port is non-zero, after the fast polling fails it uses parport_wait_event to wait for up to 10ms, waking up if an interrupt occurs.
5. COPYRIGHT ▲