linux-kernel - Re: [PATCH] iio: at91-sama5d2_adc: fix iio_triggered_buffer

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Date:   Mon, 25 Nov 2019 15:03:31 +0000
From:   "Ardelean, Alexandru" <alexandru.Ardelean@...log.com>
To:     "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-iio@...r.kernel.org" <linux-iio@...r.kernel.org>
CC:     "nicolas.ferre@...rochip.com" <nicolas.ferre@...rochip.com>,
        "jic23@...nel.org" <jic23@...nel.org>,
        "ludovic.desroches@...rochip.com" <ludovic.desroches@...rochip.com>,
        "knaack.h@....de" <knaack.h@....de>,
        "lars@...afoo.de" <lars@...afoo.de>,
        "alexandre.belloni@...tlin.com" <alexandre.belloni@...tlin.com>,
        "pmeerw@...erw.net" <pmeerw@...erw.net>
Subject: Re: [PATCH] iio: at91-sama5d2_adc: fix
 iio_triggered_buffer_{predisable,postenable} positions

On Wed, 2019-10-23 at 11:25 +0300, Alexandru Ardelean wrote:
> The iio_triggered_buffer_{predisable,postenable} functions attach/detach
> poll functions.
> 
> The iio_triggered_buffer_postenable() should be called first to attach
> the
> poll function, and then the driver can init the data to be triggered.
> 
> Similarly, iio_triggered_buffer_predisable() should be called last to
> first
> disable the data (to be triggered) and then the poll function should be
> detached.
> 
> For this driver, the predisable & postenable hooks are also need to take
> into consideration the touchscreen, so the hooks need to be put in places
> that avoid the code for that cares about it.
> 

ping here

> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@...log.com>
> ---
>  drivers/iio/adc/at91-sama5d2_adc.c | 19 ++++++++++---------
>  1 file changed, 10 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-
> sama5d2_adc.c
> index e1850f3d5cf3..ac3e5c4c9840 100644
> --- a/drivers/iio/adc/at91-sama5d2_adc.c
> +++ b/drivers/iio/adc/at91-sama5d2_adc.c
> @@ -889,20 +889,24 @@ static int at91_adc_buffer_postenable(struct
> iio_dev *indio_dev)
>  	if (!(indio_dev->currentmode & INDIO_ALL_TRIGGERED_MODES))
>  		return -EINVAL;
>  
> +	ret = iio_triggered_buffer_postenable(indio_dev);
> +	if (ret)
> +		return ret;
> +
>  	/* we continue with the triggered buffer */
>  	ret = at91_adc_dma_start(indio_dev);
>  	if (ret) {
>  		dev_err(&indio_dev->dev, "buffer postenable failed\n");
> +		iio_triggered_buffer_predisable(indio_dev);
>  		return ret;
>  	}
>  
> -	return iio_triggered_buffer_postenable(indio_dev);
> +	return 0;
>  }
>  
>  static int at91_adc_buffer_predisable(struct iio_dev *indio_dev)
>  {
>  	struct at91_adc_state *st = iio_priv(indio_dev);
> -	int ret;
>  	u8 bit;
>  
>  	/* check if we are disabling triggered buffer or the touchscreen */
> @@ -916,13 +920,8 @@ static int at91_adc_buffer_predisable(struct iio_dev
> *indio_dev)
>  	if (!(indio_dev->currentmode & INDIO_ALL_TRIGGERED_MODES))
>  		return -EINVAL;
>  
> -	/* continue with the triggered buffer */
> -	ret = iio_triggered_buffer_predisable(indio_dev);
> -	if (ret < 0)
> -		dev_err(&indio_dev->dev, "buffer predisable failed\n");
> -
>  	if (!st->dma_st.dma_chan)
> -		return ret;
> +		goto out;
>  
>  	/* if we are using DMA we must clear registers and end DMA */
>  	dmaengine_terminate_sync(st->dma_st.dma_chan);
> @@ -949,7 +948,9 @@ static int at91_adc_buffer_predisable(struct iio_dev
> *indio_dev)
>  
>  	/* read overflow register to clear possible overflow status */
>  	at91_adc_readl(st, AT91_SAMA5D2_OVER);
> -	return ret;
> +
> +out:
> +	return iio_triggered_buffer_predisable(indio_dev);
>  }
>  
>  static const struct iio_buffer_setup_ops at91_buffer_setup_ops = {