linux-kernel - RE: [PATCH v2 14/16] iio: adc: max1027: Don't just sleep when the EOC interrupt is available

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Date:   Mon, 6 Sep 2021 09:38:02 +0000
From:   "Sa, Nuno" <Nuno.Sa@...log.com>
To:     Miquel Raynal <miquel.raynal@...tlin.com>,
        Jonathan Cameron <jic23@...nel.org>,
        Lars-Peter Clausen <lars@...afoo.de>,
        "linux-iio@...r.kernel.org" <linux-iio@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Thomas Petazzoni <thomas.petazzoni@...tlin.com>
Subject: RE: [PATCH v2 14/16] iio: adc: max1027: Don't just sleep when the EOC
 interrupt is available



> -----Original Message-----
> From: Miquel Raynal <miquel.raynal@...tlin.com>
> Sent: Thursday, September 2, 2021 11:15 PM
> To: Jonathan Cameron <jic23@...nel.org>; Lars-Peter Clausen
> <lars@...afoo.de>; linux-iio@...r.kernel.org; linux-
> kernel@...r.kernel.org
> Cc: Thomas Petazzoni <thomas.petazzoni@...tlin.com>; Sa, Nuno
> <Nuno.Sa@...log.com>; Miquel Raynal <miquel.raynal@...tlin.com>
> Subject: [PATCH v2 14/16] iio: adc: max1027: Don't just sleep when the
> EOC interrupt is available
> 
> [External]
> 
> The interrupt will fire upon end of conversion. This currently can
> happen in two situations: either the cnvst trigger was enabled and
> toggled, or a single read was requested and the data is ready. The first
> situation is already covered while the second is not. Instead, a waiting
> delay is applied. Let's handle these interrupts more properly by adding
> second path in our EOC helper.
> 
> Rename the interrupt handler to a more generic name as it won't only
> handle triggered situations.
> 
> Signed-off-by: Miquel Raynal <miquel.raynal@...tlin.com>
> ---
>  drivers/iio/adc/max1027.c | 31 ++++++++++++++++++++++++++++---
>  1 file changed, 28 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iio/adc/max1027.c b/drivers/iio/adc/max1027.c
> index b85fe0a48ff9..e734d32a5507 100644
> --- a/drivers/iio/adc/max1027.c
> +++ b/drivers/iio/adc/max1027.c
> @@ -256,15 +256,27 @@ struct max1027_state {
>  	struct iio_trigger		*trig;
>  	__be16				*buffer;
>  	struct mutex			lock;
> +	struct completion		complete;
> 
>  	u8				reg ____cacheline_aligned;
>  };
> 
>  static int max1027_wait_eoc(struct iio_dev *indio_dev)
>  {
> +	struct max1027_state *st = iio_priv(indio_dev);
>  	unsigned int conversion_time =
> MAX1027_CONVERSION_UDELAY;
> +	int ret;
> 
> -	usleep_range(conversion_time, conversion_time * 2);
> +	if (st->spi->irq) {
> +		ret = wait_for_completion_timeout(&st->complete,
> +
> msecs_to_jiffies(1000));
> +		if (!ret)
> +			return ret;
> +
> +		reinit_completion(&st->complete);

I would call this before the waiting...

- Nuno Sá