On Wed, Nov 18, 2015 at 10:46:52AM +0100, Philipp Zabel wrote: > Hi Hans, > > Am Montag, den 16.11.2015, 18:13 +0100 schrieb Hans de Goede: > > On 16-11-15 18:01, Philipp Zabel wrote: > > > If there are two devices sharing the same reset line that is initially > > > held asserted, do the two drivers somehow have to synchronize before > > > releasing the reset together? > > > > Not to my knowledge, I suggest that we simply treat this same as > > regulators / clocks where the first one to enable it actually gets > > it enabled (de-asserted in case of a reset), and the last one > > to disable (assert) it (so dropping the usage counter back to 0) leads > > to it being asserted again. > > > > This seems to work well enough for clocks / regulators and phys, and > > at least for my use-case it should work fine for the shared reset too > > (I will test to make sure of course). > > > > So from my pov a simple counter should suffice, does that work for you ? > > I don't quite understand what counting will help with, then. The first > driver to call reset_control_deassert will deassert the reset, whether > you count or not. > But if the two drivers have deasserted an initially asserted reset, a > reset_control_assert for one of them will silently fail. Then maybe we can just make it return an error when someone calls _assert or _reset on a reset line that has more than one user? Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com
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