patch-2.3.99-pre6 linux/include/linux/parport.h

• Lines: 47
• Date: Wed Apr 26 15:31:16 2000
• Orig file: v2.3.99-pre5/linux/include/linux/parport.h
• Orig date: Wed Feb 16 17:03:52 2000

diff -u --recursive --new-file v2.3.99-pre5/linux/include/linux/parport.h linux/include/linux/parport.h
@@ -380,8 +380,26 @@
 
 extern void parport_release(struct pardevice *dev);
 
-/* parport_yield relinquishes the port if it would be helpful to other
-   drivers.  The return value is the same as for parport_claim.  */
+/**
+ * parport_yield - relinquish a parallel port temporarily
+ * @dev: a device on the parallel port
+ *
+ * This function relinquishes the port if it would be helpful to other
+ * drivers to do so.  Afterwards it tries to reclaim the port using
+ * parport_claim(), and the return value is the same as for
+ * parport_claim().  If it fails, the port is left unclaimed and it is
+ * the driver's responsibility to reclaim the port.
+ *
+ * The parport_yield() and parport_yield_blocking() functions are for
+ * marking points in the driver at which other drivers may claim the
+ * port and use their devices.  Yielding the port is similar to
+ * releasing it and reclaiming it, but is more efficient because no
+ * action is taken if there are no other devices needing the port.  In
+ * fact, nothing is done even if there are other devices waiting but
+ * the current device is still within its "timeslice".  The default
+ * timeslice is half a second, but it can be adjusted via the /proc
+ * interface.
+ **/
 extern __inline__ int parport_yield(struct pardevice *dev)
 {
 	unsigned long int timeslip = (jiffies - dev->time);
@@ -391,8 +409,15 @@
 	return parport_claim(dev);
 }
 
-/* parport_yield_blocking is the same but uses parport_claim_or_block
-   instead of parport_claim.  */
+/**
+ * parport_yield_blocking - relinquish a parallel port temporarily
+ * @dev: a device on the parallel port
+ *
+ * This function relinquishes the port if it would be helpful to other
+ * drivers to do so.  Afterwards it tries to reclaim the port using
+ * parport_claim_or_block(), and the return value is the same as for
+ * parport_claim_or_block().
+ **/
 extern __inline__ int parport_yield_blocking(struct pardevice *dev)
 {
 	unsigned long int timeslip = (jiffies - dev->time);