Re: [PATCH v2 3/8] iio: at91_adc: pass ref to IIO device via param for int function

["Ardelean, Alexandru" <alexandru.Ardelean@analog.com>]

On Sat, 2020-05-16 at 18:17 +0100, Jonathan Cameron wrote:
> [External]
> 
> On Thu, 14 May 2020 16:17:05 +0300
> Alexandru Ardelean <alexandru.ardelean@analog.com> wrote:
> 
> > Since there will be some changes to how iio_priv_to_dev() is implemented,
> > it could be that the helper becomes a bit slower, as it will be hidden away
> > in the IIO core.
> > 
> > For this driver, the IIO device can be passed directly as a parameter to
> > the at91_ts_sample() function, thus making it immune to the change of
> > iio_priv_to_dev().
> > The function gets called in an interrupt context.
> > 
> > Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
> I wonder. Should we just pass the struct device?  It's only used for
> error printing I think, so we could make that explicit.

I was also thinking that for this series, [for some drivers] it would make sense
to put a reference to indio_dev on the state-struct; and just return it.
I'll see about it.
I am feeling that sometimes these IIO core cleanups end up being more than I
want to do. But I'll try to see about it. Maybe I can make time or delegate some
of this.

My personal interest with them, is to reduce my complaints during reviews.
People starting to write IIO drivers: well, I can see their frustration [on
their faces] when I complain that they shouldn't use something, and they copied
it from somewhere.


> 
> I'm not that bothered either way though.
> 
> Jonathan
> 
> > ---
> >  drivers/iio/adc/at91_adc.c | 5 ++---
> >  1 file changed, 2 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
> > index 0368b6dc6d60..5999defe47cd 100644
> > --- a/drivers/iio/adc/at91_adc.c
> > +++ b/drivers/iio/adc/at91_adc.c
> > @@ -287,13 +287,12 @@ static void handle_adc_eoc_trigger(int irq, struct
> > iio_dev *idev)
> >  	}
> >  }
> >  
> > -static int at91_ts_sample(struct at91_adc_state *st)
> > +static int at91_ts_sample(struct iio_dev *idev, struct at91_adc_state *st)
> >  {
> >  	unsigned int xscale, yscale, reg, z1, z2;
> >  	unsigned int x, y, pres, xpos, ypos;
> >  	unsigned int rxp = 1;
> >  	unsigned int factor = 1000;
> > -	struct iio_dev *idev = iio_priv_to_dev(st);
> >  
> >  	unsigned int xyz_mask_bits = st->res;
> >  	unsigned int xyz_mask = (1 << xyz_mask_bits) - 1;
> > @@ -449,7 +448,7 @@ static irqreturn_t at91_adc_9x5_interrupt(int irq, void
> > *private)
> >  
> >  		if (status & AT91_ADC_ISR_PENS) {
> >  			/* validate data by pen contact */
> > -			at91_ts_sample(st);
> > +			at91_ts_sample(idev, st);
> >  		} else {
> >  			/* triggered by event that is no pen contact, just read
> >  			 * them to clean the interrupt and discard all.