Re: [PATCHv8 1/2] pwm: Add Allwinner SoC support

[Alexandre Belloni]

Hi,

On 20/10/2014 at 00:22:57 +0300, Vladimir Zapolskiy wrote :
> > +struct sun4i_pwm_chip {
> > +	struct pwm_chip chip;
> > +	struct clk *clk;
> > +	void __iomem *base;
> > +	struct mutex ctrl_lock;
> 
> why do you use mutex? I haven't found any blocking subcalls under
> protection, a spinlock seems to fit better here.
> 

A mutex here will do the right thing. The lock is never taken in
interrupt context and a mutex is spinning for a few cycles before
putting the thread to sleep. I'm not sure why you feel a spinlock would
be better here.

-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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