Re: [PATCH] iio: adc: stm32-adc: dma transfers cleanup

[Jonathan Cameron <jic23@kernel.org>]

On Thu, 5 Nov 2020 18:38:27 +0100
Fabrice Gasnier <fabrice.gasnier@st.com> wrote:

> On 11/5/20 3:29 PM, Olivier Moysan wrote:
> > - Remove processing related to DMA in irq handler as this
> > data transfer is managed directly in DMA callback.
> > - Update comment in stm32_adc_set_watermark() function.
> > 
> > Signed-off-by: Olivier Moysan <olivier.moysan@st.com>  
> 
> Hi Olivier,
> 
> Reviewed-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Applied to the togreg branch of iio.git and pushed out as testing for
the autobuilders to poke at it.

Thanks,

Jonathan

> 
> Thanks,
> Fabrice
> > ---
> >  drivers/iio/adc/stm32-adc.c | 29 ++++++-----------------------
> >  1 file changed, 6 insertions(+), 23 deletions(-)
> > 
> > diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
> > index b3f31f147347..08be826f1462 100644
> > --- a/drivers/iio/adc/stm32-adc.c
> > +++ b/drivers/iio/adc/stm32-adc.c
> > @@ -1310,7 +1310,7 @@ static int stm32_adc_set_watermark(struct iio_dev *indio_dev, unsigned int val)
> >  	 * dma cyclic transfers are used, buffer is split into two periods.
> >  	 * There should be :
> >  	 * - always one buffer (period) dma is working on
> > -	 * - one buffer (period) driver can push with iio_trigger_poll().
> > +	 * - one buffer (period) driver can push data.
> >  	 */
> >  	watermark = min(watermark, val * (unsigned)(sizeof(u16)));
> >  	adc->rx_buf_sz = min(rx_buf_sz, watermark * 2 * adc->num_conv);
> > @@ -1573,31 +1573,14 @@ static irqreturn_t stm32_adc_trigger_handler(int irq, void *p)
> >  
> >  	dev_dbg(&indio_dev->dev, "%s bufi=%d\n", __func__, adc->bufi);
> >  
> > -	if (!adc->dma_chan) {
> > -		/* reset buffer index */
> > -		adc->bufi = 0;
> > -		iio_push_to_buffers_with_timestamp(indio_dev, adc->buffer,
> > -						   pf->timestamp);
> > -	} else {
> > -		int residue = stm32_adc_dma_residue(adc);
> > -
> > -		while (residue >= indio_dev->scan_bytes) {
> > -			u16 *buffer = (u16 *)&adc->rx_buf[adc->bufi];
> > -
> > -			iio_push_to_buffers_with_timestamp(indio_dev, buffer,
> > -							   pf->timestamp);
> > -			residue -= indio_dev->scan_bytes;
> > -			adc->bufi += indio_dev->scan_bytes;
> > -			if (adc->bufi >= adc->rx_buf_sz)
> > -				adc->bufi = 0;
> > -		}
> > -	}
> > -
> > +	/* reset buffer index */
> > +	adc->bufi = 0;
> > +	iio_push_to_buffers_with_timestamp(indio_dev, adc->buffer,
> > +					   pf->timestamp);
> >  	iio_trigger_notify_done(indio_dev->trig);
> >  
> >  	/* re-enable eoc irq */
> > -	if (!adc->dma_chan)
> > -		stm32_adc_conv_irq_enable(adc);
> > +	stm32_adc_conv_irq_enable(adc);
> >  
> >  	return IRQ_HANDLED;
> >  }
> >