[PATCH 1/5] iio:adc:at91_adc8xx: introduce new atmel adc driver
Ludovic Desroches
ludovic.desroches at atmel.com
Wed Dec 23 02:48:33 PST 2015
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
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