RE: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

["Hiremath, Vaibhav" <hvaibhav@ti.com>]

On Tue, Mar 06, 2012 at 04:25:30, Tony Lindgren wrote:
> Hi,
> 
> * Vaibhav Hiremath <hvaibhav@ti.com> [120119 06:01]:
> > OMAP device has 32k-sync timer which is currently used as a
> > clocksource in the kernel (omap2plus_defconfig).
> > The current implementation uses compile time selection between
> > gp-timer and 32k-sync timer, which breaks multi-omap build for
> > the devices like AM33xx, where 32k-sync timer is not available.
> > 
> > So use hwmod database lookup mechanism, through which at run-time
> > we can identify availability of 32k-sync timer on the device,
> > else fall back to gp-timer.
> ...
> 
> > --- a/arch/arm/plat-omap/counter_32k.c
> > +++ b/arch/arm/plat-omap/counter_32k.c
> > @@ -69,52 +69,55 @@ void read_persistent_clock(struct timespec *ts)
> >  
> >  int __init omap_init_clocksource_32k(void)
> >  {
> > -	static char err[] __initdata = KERN_ERR
> > -			"%s: can't register clocksource!\n";
> > -
> > -	if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
> > -		u32 pbase;
> > -		unsigned long size = SZ_4K;
> > -		void __iomem *base;
> > -		struct clk *sync_32k_ick;
> > -
> > -		if (cpu_is_omap16xx()) {
> > -			pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > -			size = SZ_1K;
> > -		} else if (cpu_is_omap2420())
> > -			pbase = OMAP2420_32KSYNCT_BASE + 0x10;
> > -		else if (cpu_is_omap2430())
> > -			pbase = OMAP2430_32KSYNCT_BASE + 0x10;
> > -		else if (cpu_is_omap34xx())
> > -			pbase = OMAP3430_32KSYNCT_BASE + 0x10;
> > -		else if (cpu_is_omap44xx())
> > -			pbase = OMAP4430_32KSYNCT_BASE + 0x10;
> > -		else
> > +	u32 pbase;
> > +	unsigned long size = SZ_4K;
> > +	void __iomem *base;
> > +	struct clk *sync_32k_ick;
> > +
> > +	if (cpu_is_omap16xx()) {
> > +		pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
> > +		size = SZ_1K;
> > +	} else if (cpu_class_is_omap2()) {
> > +		struct omap_hwmod *oh;
> > +		const char *oh_name = "counter_32k";
> > +
> > +		oh = omap_hwmod_lookup(oh_name);
> > +		if (!oh || oh->slaves_cnt == 0) {
> > +			pr_err("Could not lookup %s hwmod\n", oh_name);
> >  			return -ENODEV;
> > +		}
> > +		pbase = oh->slaves[0]->addr->pa_start + 0x10;
> > +	} else {
> > +		return -ENODEV;
> > +	}
> 
> How about have separate omap1 and omap2+ init functions that
> call a common function and passes the pbase as a parameter?
> 
> That way we can get rid of the cpu_is_omapxxxx tests here.
> 

Tony,

In the morning, I replied very soon, without much thinking...

Just now I started working on the patch, I was just reviewing the code, 
and I felt that, it is unnecessary to split the code between omap1 and 
omap2+.

The reason is,

Currently Only OMAP16xx base-address is hardcoded with cpu_is_omap16xx() 
macro, For all other omap family of devices the complete information is fetched from HWDMO api's/data.

Thanks,
Vaibhav

> Regards,
> 
> Tony 
>