[PATCH 3/5] ARM: dove: create a proper PMU driver for power domains, PMU IRQs and resets

Russell King - ARM Linux linux at arm.linux.org.uk
Mon Apr 28 05:17:26 PDT 2014


On Mon, Apr 28, 2014 at 01:55:40PM +0200, Ulf Hansson wrote:
> On 27 April 2014 15:29, Russell King <rmk+kernel at arm.linux.org.uk> wrote:
> > The PMU device contains an interrupt controller, power control and
> > resets.  The interrupt controller is a little sub-standard in that
> > there is no race free way to clear down pending interrupts, so we try
> > to avoid problems by reducing the window as much as possible, and
> > clearing as infrequently as possible.
> >
> > The interrupt support is implemented using an IRQ domain, and the
> > parent interrupt referenced in the standard DT way.
> >
> > The power domains and reset support is closely related - there is a
> > defined sequence for powering down a domain which is tightly coupled
> > with asserting the reset.  Hence, it makes sense to group these two
> > together.
> >
> > This patch adds the core PMU driver: power domains must be defined in
> > the DT file in order to make use of them.  The reset controller can
> > be referenced in the standard way for reset controllers.
> 
> Hi Russell,
> 
> This patch would be simplified if this was based upon the not yet
> merged patchset from Tomasz Figa, "[PATCH v3 0/3] Generic Device Tree
> based power domain look-up".
> 
> For example you would likely not need to add some of the marvel
> specific DT bindings, and you wouldn’t need the bus_notifiers to add
> devices to the power domain. I guess I just though it could be useful
> input to consider while going forward, unless you already knew.

Does that apply to 3.14?

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