On Tue, Jan 21, 2014 at 08:43:39PM +0100, Thierry Reding wrote: > The idea behind this is that only a single user can have access to a > given PWM device at a time. The PWM device's PWMF_REQUESTED flag is set > (and cleared) under the pwm_lock and any subsequent users will not be > able to use that specific device (pwm_request() return -EBUSY). > > There is obviously an assumption here that each user knows what they are > doing and aren't calling any of the public pwm_*() functions > concurrently. I haven't come across a situation where this is actually a > problem because typically these functions are called either via sysfs or > some other higher-level where synchronization is already properly > handled. > > So the only thing that drivers should be taking care of is synchronizing > access to registers common to multiple PWM devices.
OK, and since LPSS PWM don't share registers we shouldn't need to do anything here. > Does that clarify things? It does for me, thanks for the explanation. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
