linux-kernel - Re: [PATCH v5 2/8] clk: mmp: switch to GENMASK()

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Message-ID: <1437570245.8014.33.camel@linux.intel.com>
Date:	Wed, 22 Jul 2015 16:04:05 +0300
From:	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:	Stephen Boyd <sboyd@...eaurora.org>
Cc:	linux-kernel@...r.kernel.org, Sascha Hauer <kernel@...gutronix.de>,
	Peter De Schrijver <pdeschrijver@...dia.com>,
	Tero Kristo <t-kristo@...com>,
	Russell King <linux@....linux.org.uk>,
	Dinh Nguyen <dinguyen@...nsource.altera.com>
Subject: Re: [PATCH v5 2/8] clk: mmp: switch to GENMASK()

On Tue, 2015-07-21 at 16:53 -0700, Stephen Boyd wrote:
> On 07/13, Andy Shevchenko wrote:
> > diff --git a/drivers/clk/mmp/clk.h b/drivers/clk/mmp/clk.h
> > index adf9b71..f5fdb0e 100644
> > --- a/drivers/clk/mmp/clk.h
> > +++ b/drivers/clk/mmp/clk.h
> > @@ -39,7 +39,7 @@ extern struct clk *mmp_clk_register_factor(const 
> > char *name,
> >  
> >  /* Clock type "mix" */
> >  #define MMP_CLK_BITS_MASK(width, shift)			\
> > -		(((1 << (width)) - 1) << (shift))
> > +		(GENMASK((width) - 1, 0) << (shift))
> 
> This can push the shift into the GENMASK instance too:

Too not optimal. I checked the assembly.

> 
> 		(GENMASK((width) - 1 + (shift), (shift))
> 
> >  #define MMP_CLK_BITS_GET_VAL(data, width, shift)	\
> >  		((data & MMP_CLK_BITS_MASK(width, shift)) >> 
> > (shift))
> >  #define MMP_CLK_BITS_SET_VAL(val, width, shift)		\
> > -- 
> > 2.1.4
> > 
> 

-- 
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Intel Finland Oy
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