[PATCH 03/14] ARM: LPC32XX: Clock driver

[Kevin Wells]

> > +
> > +static inline void clk_unlock(void)
> > +{
> > +	mutex_unlock(&clkm_lock);
> > +}
> > +
> > +static void local_clk_disable(struct clk *clk)
> > +{
> > +	/* Don't attempt to disable clock if it has no users */
> WARN_ON(clk->usecount <= 0)?

Is the expectation that the driver will always enable a clock
prior to disabling it and balance each disable with a previous
enable? I'm seeing a specific case of disable first, some
register accesses, and then clock enable on the amba clcd
driver (the warning fires on the first disable before enable).

[<c002b098>] (clk_disable+0x0/0x34) from [<c014555c>] (clcdfb_disable+0xa8/0xb0)
 r5:00000000 r4:c3c10400
[<c01454b4>] (clcdfb_disable+0x0/0xb0) from [<c014570c>] (clcdfb_set_par+0x50/0xe8)
 r6:00000028 r5:c3c10400 r4:c3c10400
[<c01456bc>] (clcdfb_set_par+0x0/0xe8) from [<c0140884>] (fbcon_init+0x2f4/0x42c)

> 
> > +	if (clk->usecount > 0) {
> > +		clk->usecount--;
> > +
> > +		/* Only disable clock when it has no more users */
> > +		if ((clk->usecount == 0) && (clk->enable))
> > +			clk->enable(clk, 0);
> > +
> > +		/* Check parent clocks, they may need to be disabled too */
> > +		if (clk->parent)
> > +			local_clk_disable(clk->parent);
> > +	}
> > +}
> > +