[PATCH 1/2] [ARM] [IMX]: Removed superfluous checks for argument validity.

[Vladimir Zapolskiy]

Hi Uwe,

2010/3/18 Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
>
> On Wed, Mar 17, 2010 at 01:34:50PM +0300, Vladimir Zapolskiy wrote:
> > Hello Uwe,
> >
> > __clk_enable() and __clk_disable() are recursive with another arguments,
> > that means it is hardly possible to remove the checks from them.
> ah, at least the check for NULL cannot go away.  However IS_ERR(clk)
> should hardly matter, shouldn't it?
>
> Maybe the generated code is more optimal when doing:
>
>        static void __clk_disable(struct clk *clk)
>        {
>                WARN_ON(!clk->usecount);
>
>                if (clk->parent)
>                        __clk_disable(clk->parent);
>
>                if (clk->secondary)
>                        __clk_disable(clk->secondary);
>
>                if (!(--clk->usecount) && clk->disable)
>                        clk->disable(clk);
>        }
>
>        void clk_disable(struct clk *clk)
>        {
>                BUG_ON(clk == NULL || IS_ERR(clk));
>                mutex_lock(&clocks_mutex);
>                __clk_disable(clk);
>                mutex_unlock(&clocks_mutex);
>        }
>
> So unless the compiler optimizes well, this reduces the calls of
> __clk_disable from three to one for a clock without parent and
> secondary.
>

I hope I got your view on optimization of calls, because I just wanted
to reduce 6 LOCs with the patch :)
Anyway better to do both optimizations at the same time.

> While at it I wonder if it isn't more correct in __clk_disable to
> disable the clock first and only then parent and secondary?!
>

Looks like a reasonable assumption.

> Best regards
> Uwe
>

Best wishes,
Vladimir