Re: [PATCH v6 3/8] ARM: sunxi: Move the clock protection to machine hooks

From: Arnd Bergmann
Date: Wed Apr 23 2014 - 09:33:05 EST


On Wednesday 23 April 2014 15:17:20 Maxime Ripard wrote:
> > > +#include <linux/clk.h>
> > > #include <linux/init.h>
> > > #include <linux/of_platform.h>
> > >
> > > @@ -19,9 +20,17 @@
> > >
> > > static void __init sun4i_dt_init(void)
> > > {
> > > + struct clk *clk;
> > > +
> > > sunxi_setup_restart();
> > >
> > > of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
> > > +
> > > + /* Make sure the clocks we absolutely need are enabled */
> > > + /* DDR clock */
> > > + clk = clk_get(NULL, "pll5_ddr");
> > > + if (!IS_ERR(clk))
> > > + clk_prepare_enable(clk);
> > > }
> >
> > Isn't there already DT syntax to do the same? If not, should there be?
>
> I don't think there is, and I gave some thought about it too. But
> something a la regulator-always-on wouldn't work with clocks with
> multiple outputs (like pll5), because you might need to leave only one
> of the output enabled, but not the others, and I couldn't think of a
> nice way to do so.
>
> If you have one, I'd be happy to implement it.

We had a discussion a while ago about encoding default settings for clock
providers in the clock provider nodes. I don't remember the details
unfortunately.

Mike, can you explain how this should be done?

Arnd
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