From mboxrd@z Thu Jan  1 00:00:00 1970
From: ludovic.desroches@atmel.com (Ludovic Desroches)
Date: Wed, 23 Dec 2015 11:48:33 +0100
Subject: [PATCH 1/5] iio:adc:at91_adc8xx: introduce new atmel adc driver
In-Reply-To: <20151223102700.GC2789@odux.rfo.atmel.com>
References: <1450689852-22763-1-git-send-email-ludovic.desroches@atmel.com>
 <1450689852-22763-2-git-send-email-ludovic.desroches@atmel.com>
 <56799798.203@kernel.org>
 <20151223102700.GC2789@odux.rfo.atmel.com>
Message-ID: <20151223104833.GE2789@odux.rfo.atmel.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Wed, Dec 23, 2015 at 11:27:00AM +0100, Ludovic Desroches wrote:
> On Tue, Dec 22, 2015 at 06:34:00PM +0000, Jonathan Cameron wrote:
> > On 21/12/15 09:24, Ludovic Desroches wrote:
> > > This driver supports the new version of the Atmel ADC device introduced
> > > with the SAMA5D2 SoC family.
> > > 

[...]

> > > +static irqreturn_t at91_adc_interrupt(int irq, void *private)
> > > +{
> > > +	struct iio_dev *indio = private;
> > > +	struct at91_adc_state *st = iio_priv(indio);
> > > +	u32 status = at91_adc_readl(st, ADC_ISR);
> > > +
> > > +	status &= at91_adc_readl(st, ADC_IMR);
> > > +	if (status & 0xFFF) {
> > > +		st->last_value = at91_adc_readl(st, st->chan->address);
> > If this is a polled read - is there any reason to read this value here
> > rather than outside the interrupt?
> 
> No it can be done outside the interrupt. I have taken some parts from the
> previous driver but it was reading a register used by all the channels
> when it has been designed. So yes there is probably no more reason to
> read it into the interrupt.
> 

Thinking about it. Is it really useful to move reading outside the
interrupt?

By the way this is not a polled read.

> > > +		st->done = true;
> > > +		wake_up_interruptible(&st->wq_data_available);
> > > +	}
> > > +
> > > +	return IRQ_HANDLED;
> > > +}

Ludovic