On Mon, Feb 24, 2014 at 05:22:43PM +0100, Maxime Ripard wrote: > Right now, AHB is an indirect child clock of the CPU clock. If that happens to > change, since the CPU clock has no other consumers declared in Linux, it would > be shut down, which is not really a good idea. > > Prevent this by forcing it enabled. > > Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx> > --- > drivers/clk/sunxi/clk-sunxi.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/clk/sunxi/clk-sunxi.c b/drivers/clk/sunxi/clk-sunxi.c > index 23baad9..cedaf4b 100644 > --- a/drivers/clk/sunxi/clk-sunxi.c > +++ b/drivers/clk/sunxi/clk-sunxi.c > @@ -1301,6 +1301,14 @@ static void __init sunxi_clock_protect(void) > clk_prepare_enable(clk); > clk_put(clk); > } > + > + /* CPU clocks - sun6i */ > + clk = clk_get(NULL, "cpu"); > + if (!IS_ERR(clk)) { > + clk_prepare_enable(clk); > + clk_put(clk); > + } This is broken. I'm not sure what's difficult to grasp about the concept of "while a clock is in use, you should keep a reference to that clock". That implies that if you get a clock, and then enable it, you don't put the clock until you've disabled it. The only reason the core doesn't check for this kind of thing is that a clock may be shared, so it's entirely possible for a correctly written driver to have a clock which is still enabled at put time - but enabled by an entirely different driver. However, that's no excuse for this kind of sloppiness. -- FTTC broadband for 0.8mile line: now at 9.7Mbps down 460kbps up... slowly improving, and getting towards what was expected from it. -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html