RE: [PATCH] omap3: Check return values for clk_get

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> -----Original Message-----
> From: linux-omap-owner@xxxxxxxxxxxxxxx 
> [mailto:linux-omap-owner@xxxxxxxxxxxxxxx] On Behalf Of Premi, Sanjeev
> Sent: Thursday, January 28, 2010 7:42 PM
> To: Kevin Hilman
> Cc: linux-omap@xxxxxxxxxxxxxxx
> Subject: RE: [PATCH] omap3: Check return values for clk_get
> 
>  
> > -----Original Message-----
> > From: Kevin Hilman [mailto:khilman@xxxxxxxxxxxxxxxxxxx] 
> > Sent: Saturday, January 09, 2010 4:08 AM
> > To: Premi, Sanjeev
> > Cc: linux-omap@xxxxxxxxxxxxxxx
> > Subject: Re: [PATCH] omap3: Check return values for clk_get
> > 
> > Sanjeev Premi <premi@xxxxxx> writes:
> > 
> > > This patch checks if clk_get() returned success for
> > > the clocks used in function omap2_clk_arch_init().
> > >
> > > Signed-off-by: Sanjeev Premi <premi@xxxxxx>
> > > ---
> > >  arch/arm/mach-omap2/clock34xx.c |   25 +++++++++++++++++++++++--
> > >  1 files changed, 23 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/arch/arm/mach-omap2/clock34xx.c 
> > b/arch/arm/mach-omap2/clock34xx.c
> > > index d4217b9..2c2165b 100644
> > > --- a/arch/arm/mach-omap2/clock34xx.c
> > > +++ b/arch/arm/mach-omap2/clock34xx.c
> > > @@ -316,17 +316,38 @@ static int __init omap2_clk_arch_init(void)
> > >  {
> > >  	struct clk *osc_sys_ck, *dpll1_ck, *arm_fck, *core_ck;
> > >  	unsigned long osc_sys_rate;
> > > +	short err = 0 ;
> > >  
> > >  	if (!mpurate)
> > >  		return -EINVAL;
> > >  
> > > -	/* XXX test these for success */
> > >  	dpll1_ck = clk_get(NULL, "dpll1_ck");
> > > +	if (dpll1_ck == NULL) {
> > 
> > All of these checks should be of the form
> > 
> >         if (IS_ERR(<clk>))       
> > 
> > instead of NULL pointer checks.
> 
> Kevin,
> 
>     In include/linux/err.h
> 
>     #define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO)
> 
>     static inline long PTR_ERR(const void *ptr)
>     {
>         return (long) ptr;
>     }
> 
>     static inline long IS_ERR(const void *ptr)
>     {
>         return IS_ERR_VALUE((unsigned long)ptr);
>     }
> 
>     I believe you wanted me to use PTR_ERR(); not IS_ERR().
> 

Kevin,

  Ignore this comment.

Best regards,
Sanjeev

> > 
> > You could also do something more compact like this, which takes
> > care of the error check and warning print:
> > 
> >         if (WARN(IS_ERR(<clk ptr>), "Failed to get <name>\n"))
> > 
> [sp] Sure will compact it.
> 
> > > +		err = 1;
> > > +		pr_err("*** Failed to get dpll1_ck.\n");
> > > +	}
> > > +
> > >  	arm_fck = clk_get(NULL, "arm_fck");
> > > +	if (arm_fck == NULL) {
> > > +		err = 1;
> > > +		pr_err("*** Failed to get arm_fck.\n");
> > > +	}
> > > +
> > >  	core_ck = clk_get(NULL, "core_ck");
> > > +	if (core_ck == NULL) {
> > > +		err = 1;
> > > +		pr_err("*** Failed to get core_ck.\n");
> > > +	}
> > > +
> > >  	osc_sys_ck = clk_get(NULL, "osc_sys_ck");
> > > +	if (osc_sys_ck == NULL) {
> > > +		err = 1;
> > > +		pr_err("*** Failed to get osc_sys_ck.\n");
> > > +	}
> > > +
> > > +	if (err)
> > > +		return 1;
> > 
> > Minor issue...
> > 
> > Do you want to skip the rest of the init in case of any failure?
> > 
> > It seems like the DPLL1 is the only one that would be a 
> real failure,
> > the others just affect the clock display.
> 
> [sp] But, even when if we use bad pointers for displaying clocks, it
>      could be bad.
> 
> Best regards,
> Sanjeev
> > 
> > 
> > Kevin
> > 
> > > -	/* REVISIT: not yet ready for 343x */
> > >  	if (clk_set_rate(dpll1_ck, mpurate))
> > >  		printk(KERN_ERR "*** Unable to set MPU rate\n");
> > >  
> > > -- 
> > > 1.6.2.2
> > >
> > > --
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