On Fri, Oct 19, 2012 at 8:10 PM, Tony Lindgren <t...@atomide.com> wrote: > [Me] >> Instead: let use reserve the pins when the state is activated >> and drop them when the state is disabled, i.e. when we move to >> another state. This way different devices/functions can use the >> same pins at different times. > > Hmm doesn't this mean that we are now doing lots of extra > reserving and dropping of pins? Performance is important from > latency point of view for cases where we need to remux pins > constantly runtime PM.
It is only done in case the pinmux state is switched in runtime suspend/resume, so it's e.g. possible to just alter the pin config. But in general what you say is true. We used to to the same thing by having drivers call pinctrl_get()/pinctrl_put() in this case instead, but that went away with the introduction of states, so we cannot encode different pin sets with say pinctrl_get(dev, "foo")/pinctrl_get(dev, "bar") anymore since there is only one pinctrl handle per device, but multiple states. If this turns out to be a severe performance bottleneck, I suggest to add some additional constraint API, like pinctrl_set_pinmux_homegeneous_pinsets(true) that will at runtime select whether the pin allocation is done when getting the pinctrl handle instead. Yours, Linus Walleij -- 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/