[PATCH] clk: rockchip: add critical clock for rk3368

[Heiko Stübner]

Am Montag, 14. September 2015, 16:19:42 schrieb Mark Rutland:
> On Mon, Sep 14, 2015 at 04:06:05PM +0100, Heiko Stübner wrote:
> > Am Montag, 14. September 2015, 15:19:21 schrieb Mark Rutland:
> > > On Sun, Sep 13, 2015 at 12:20:36PM +0100, Heiko Stübner wrote:
> > > > Again a result of the gpio-clock-liberation the rk3368 needs the
> > > > pclk_pd_pmu marked as critical, to boot successfully.
> > > > 
> > > > Reported-by: Mark Rutland <mark.rutland at arm.com>
> > > > Signed-off-by: Heiko Stuebner <heiko at sntech.de>
> > > 
> > > FWIW: Tested-by: Mark Rutland <mark.rutland at arm.com>
> > > 
> > > I'm surprised that we don't describe these as critical in the DT, given
> > > that this isn't really an internal property of the clock controller, but
> > > rather what happens to be attached to it. That ship appears to have
> > > sailed, however.
> > 
> > I wouldn't necessarily think so ... what is called critical only means
> > "don't turn off when walking the clock-tree upwards".
> > 
> > The pclk_pd_pmu for example simply supplies some more clocks we don't
> > handle at all currently (pclk_pmu_noc, ...). That we currently choose to
> > ignore those [because we don't have any code nor dt-bindings to handle
> > the components supplied] sounds very much like an implementation-specific
> > detail, not something about the hardware.
> 
> Sure, but the specific case that lead to this report was the fact that
> this clock (directly?) feeds the pinctrl programming interface, and that
> fact is neither described in the DT nor handled by the driver. Surely
> that should be described and handled?

nope it doesn't :-) pclk_pd_pmu feeds pclk_gpio0.

Before the pinctrl patch, pclk_gpio0 was just statically on all the time, now 
it gets turned off when bank0 is not in use (between reads/writes and if no 
interrupts are enabled). This in turn makes the clock framework turn off 
pclk_pd_pmu (and thus its other unhandled child-clocks).