linux-kernel - Re: [PATCH 1/2] mc13783: add LED support

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Date:	Wed, 26 May 2010 13:01:08 +0100
From:	Richard Purdie <rpurdie@...ys.net>
To:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
Cc:	Uwe Kleine-K?nig <u.kleine-koenig@...gutronix.de>,
	Philippe R?tornaz <philippe.retornaz@...l.ch>,
	linux-arm-kernel@...ts.infradead.org,
	maramaopercheseimorto@...il.com, sameo@...ux.intel.com,
	s.hauer@...gutronix.de, linux-kernel@...r.kernel.org,
	valentin.longchamp@...l.ch
Subject: Re: [PATCH 1/2] mc13783: add LED support

On Mon, 2010-05-17 at 21:00 +0100, Mark Brown wrote:
> On Mon, May 17, 2010 at 09:02:42PM +0200, Uwe Kleine-K?nig wrote:
> > On Mon, May 17, 2010 at 06:40:22PM +0200, Philippe R?tornaz wrote:
> 
> > > +static void mc13783_led_set(struct led_classdev *led_cdev,
> > > +			   enum led_brightness value)
> > > +{
> > > +	struct mc13783_led *led;
> > > +
> > > +	led = container_of(led_cdev, struct mc13783_led, cdev);
> > > +	led->new_brightness = value;
> > > +	schedule_work(&led->work);
> > > +}
> 
> > I wonder why you don't set the registers directly here, but use a work
> > struct instead.
> 
> The LED API allows clients to configure the LEDs from interrupt context
> so for devices on blocking buses (like this) the driver needs to defer
> the actual implementation of the change.
> 
> It'd be nice to add helpers for this to the LED core, there's quite a
> few drivers implementing this idiom now - a flag that does the deferring
> of the set() for example.

Agreed, or a wrapper around the core which deferred implementations
could just use. I'm open to patches :)

Cheers,

Richard


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