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Subject: Re: [PATCH 1/3] iio: adxl372: Provide validate_trigger and
 validate_device callbacks
To:     Stefan Popa <stefan.popa@analog.com>, jic23@kernel.org
Cc:     Michael.Hennerich@analog.com, knaack.h@gmx.de, pmeerw@pmeerw.net,
        linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org
References: <1534776823-18703-1-git-send-email-stefan.popa@analog.com>
From:   Lars-Peter Clausen <lars@metafoo.de>
Message-ID: <1fc5f7bb-67d1-fa03-2242-b38b94a151ee@metafoo.de>
Date:   Mon, 20 Aug 2018 17:47:08 +0200
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On 08/20/2018 04:53 PM, Stefan Popa wrote:
> This patch provides a validate_device callback for the trigger which makes
> sure that other devices are rejected.
> 
> Signed-off-by: Stefan Popa <stefan.popa@analog.com
> ---
>  drivers/iio/accel/adxl372.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/drivers/iio/accel/adxl372.c b/drivers/iio/accel/adxl372.c
> index d2fdc75..5a039ba 100644
> --- a/drivers/iio/accel/adxl372.c
> +++ b/drivers/iio/accel/adxl372.c
> @@ -762,11 +762,24 @@ static int adxl372_dready_trig_set_state(struct iio_trigger *trig,
>  	return adxl372_set_interrupts(st, mask, 0);
>  }
>  
> +static int adxl372_validate_trigger(struct iio_dev *indio_dev,
> +				    struct iio_trigger *trig)
> +{
> +	struct adxl372_state *st = iio_priv(indio_dev);
> +
> +	if (st->dready_trig != trig)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
>  static const struct iio_trigger_ops adxl372_trigger_ops = {
> +	.validate_device = &iio_trigger_validate_own_device,
>  	.set_trigger_state = adxl372_dready_trig_set_state,
>  };
>  
>  static const struct iio_info adxl372_info = {
> +	.validate_trigger = &adxl372_validate_trigger,

I wonder, if the device only works with the trigger and the trigger only
works with the device should we actually register a trigger?

Seems to be just extra hassle when setting up the device without any extra
benefits.