On Mon, Jun 25, 2012 at 09:07:58AM +0300, Tomi Valkeinen wrote: > On Fri, 2012-06-22 at 19:18 +0530, Rajendra Nayak wrote: > > In preparation of OMAP moving to Common Clk Framework(CCF) add clk_prepare() > > and clk_unprepare() for the omapdss clocks. > > You used clk_prepare and clk_unprepare instead of clk_prepare_enable and > clk_disable_unprepare. I didn't check the dss driver yet, but my hunch > is that the clocks are normally not enabled/disabled from atomic > context. > > What does the prepare/unprepare actually do? Is there any benefit in > delaying preparing, i.e. is there a difference between prepare right > after clk_get, or prepare right before clk_enable? (And similarly for > unprepare)
I think you're looking at this the wrong way. Think of clk_prepare() as the _sleepable_ part of clk_enable(). So, think of clk_prepare() as ideally being placed just before clk_enable() with the exception that if that's not possible (because you're in a non-atomic context) it should be placed in a position as close to clk_enable() as possible which is atomic. Don't think of it as an extra step to be done after clk_get() but as an extra step needing to be done before clk_enable(). -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
