[alsa-devel] [PATCH] ASoC: core: Configure pin muxing via pinctrl when registering a DAI

Mark Brown broonie at opensource.wolfsonmicro.com
Tue Sep 25 14:24:56 CEST 2012

On Tue, Sep 25, 2012 at 01:56:13PM +0200, Linus Walleij wrote:

> In ux500 drivers we use *specific* (as opposed to generic) runtime PM
> code to e.g. get some hysteresis before a drivers clock and pins
> (etc) are put to sleep. Pure driver business.

Right, the runtime PM infrastructure is really useful for this stuff.

> >  Devices that can be wake sources are an example here, if they
> > are doing that then turning them completely off may break functionality
> > but you can still turn some of the device (possibly a varying selection
> > depending on usage) off.  For simple cases it works well and it'd be
> > good to have it but you end up back into ignoring errors...

> Our ux500 "sleep" state on the pins will put them into the apropriate
> wakeup mode where applicable. Since this may vary across boards
> it's even machine-specific.

> Configuring wakeup sources when going to a state named "sleep"
> seems intuitive to me atleast.

For some devices the set of wakeup sources vary depending on the current
system state - for example, if a cable is plugged into a connector we
may have to keep some additional things on to monitor activity on the
cable.  This isn't the common case, for most things a sleep state works
fine, but it does come up.

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