On Wed, Jan 07, 2015 at 10:28:29PM +0800, Vince Hsu wrote: > On 04:08:52PM Jan 07, Peter De Schrijver wrote: > > On Wed, Jan 07, 2015 at 02:27:10PM +0100, Thierry Reding wrote: > > > > > > Yeah. I plan to have the information of all the clock client of the > > > > partitions and > > > > the memory clients be defined statically in c source, e.g. pmc-tegra124.c. > > > > All modules can declare which domain they belong to in DT. One domain can > > > > be really power gated only when no module is awake. Note the clock clients > > > > of > > > > one domain might not equal to the clocks of the module. The reset is not > > > > either. > > > > So I don't get the clock and reset from module. How do you think? > > > > > > This whole situation is quite messy. The above sequence basically means > > > that drivers can't reset hardware modules because otherwise they might > > > race with the power domain code. It also means that we can't powergate > > > > The powerdomain framework won't call any powergating method as long as a > > module in the domain is still active. So as long as drivers don't try to > > reset the hw without having done a pm_runtime_get(), we shouldn't have such > > a race? > Agree. And as long as the driver has the correct reset procedure, that should > be fine to occur between power ungating and gating sequences. > > > > > > modules on demand because they might be in the same power domain as one > > > other module that's still busy. > > > > > > > The powerdomain framework keeps track of which modules are active (by hooking > > into runtime pm) and won't try to shutdown a domain unless all modules are > > inactive. > Yeah. By the way, that means we should start supporting runtime pm for all > the modules to use generic power domain. Indeed, that'll be a prerequisite before we can merge power domain support. I do have a couple of local patches that add very rudimentary runtime PM for various drivers. For starters we could probably just do the pm_runtime_enable(...); pm_runtime_get_sync(...) in the ->probe() and pm_runtime_put_sync(...); pm_runtime_disable(...); in the ->remove() callbacks for those drivers. That's by no means optimal but should get us pretty close to what we do now and still support the generic power domains. Thierry
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