On Mon, Jan 12, 2009 at 06:10:53PM +0200, Tony Lindgren wrote:
> * Russell King - ARM Linux <[email protected]> [090112 18:01]:
> > On Mon, Jan 12, 2009 at 05:35:28PM +0200, Tony Lindgren wrote:
> > > Well at least you could remove some parens.
> > > How about (dma_trigger / 32) << 19 instead?
> >
> > Oh, and further to my previous reply there is also the general principle
> > of writing what you mean. So, if you mean to clear the least significant
> > 5 bits, write it as a mask with ~0x1f, not as a divide.
> >
> > And no, you don't need ~(0x1f) - the parens there are pure noise. ~0x1f
> > does just as well and isn't in any way confusing to the compiler.
> > To put it another way, parens around a single value are completely
> > meaningless.
>
> Here's this one with the extra parens removed.
If you're concerned about useless parens, then...
> diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c
> index 692d2b4..660a4eb 100644
> --- a/arch/arm/plat-omap/dma.c
> +++ b/arch/arm/plat-omap/dma.c
> @@ -279,10 +279,7 @@ void omap_set_dma_transfer_params(int lch, int
> data_type, int elem_count,
>
> val = dma_read(CCR(lch));
> val &= ~(3 << 19);
> - if (dma_trigger > 63)
> - val |= 1 << 20;
> - if (dma_trigger > 31)
> - val |= 1 << 19;
> + val |= ((dma_trigger & ~0x1f) << 14);
>
> val &= ~(0x1f);
> val |= (dma_trigger & 0x1f);
should change to:
val = dma_read(CCR(lch));
val &= ~(3 << 19);
val |= (dma_trigger & ~0x1f) << 14;
val &= ~0x1f;
val |= dma_trigger & 0x1f;
--
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