Im working on a pc87366_gpio module, and it seems necessary
to coordinate locking in some way.
The simplest thing seems to be to EXPORT_SYMBOL the 2
semaphores in pc87360_data, but then I looked more closely,
and found something I dont understand...
/*
* Client data (each client gets its own)
*/
struct pc87360_data {
struct i2c_client client;
struct semaphore lock;
struct semaphore update_lock;
How is it possible to have each client get a separate struct
and separate locks, and still get any protection ?
Do semaphores magically interlock with other semaphores
protecting the same resource ? And how do they know what
theyre protecting ?
I see plenty of up/down ops on the lock, but no place where theyre
told what theyre locking access to.
Am I missing something ?
Do the earlier chips, 60, 65, etc also have a GPIO section,
or is it just the 66 ?
