Warning at kernel/mutex.c

[s.hauer@pengutronix.de (Sascha Hauer)]

On Tue, Oct 18, 2011 at 04:45:51PM -0200, Fabio Estevam wrote:
> 2011/10/18 Uwe Kleine-K?nig <u.kleine-koenig@pengutronix.de>:
> 
> >> ?static LIST_HEAD(clocks);
> >> ?static DEFINE_MUTEX(clocks_mutex);
> >> +static DEFINE_SPINLOCK(clock_lock);
> > If clocks_mutex is unused now, please remove it. If it's not unused you
> > probably introduced a problem with your patch.
> 
> clocks_mutex is still used in clk_set_rate and clk_set_parent.
> 
> Should it be converted to spinlocks too?
>

The mutex currently used protects two things: The clock tree and the
clock registers. If we use a mutex for the parent/rate functions and
a spinlock for enable/disable we must make sure that both function sets
do not access the same registers. I *think* this is the case on all
i.MX, but I haven't really checked this.

Sascha

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