linux-kernel - Re: [PATCH 13/16] iio: adc: max1027: Prepare re-using the EOC interrupt

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Date:   Mon, 30 Aug 2021 11:30:03 +0100
From:   Jonathan Cameron <jic23@...nel.org>
To:     Miquel Raynal <miquel.raynal@...tlin.com>
Cc:     Lars-Peter Clausen <lars@...afoo.de>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        linux-iio@...r.kernel.org, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 13/16] iio: adc: max1027: Prepare re-using the EOC
 interrupt

On Wed, 18 Aug 2021 13:11:36 +0200
Miquel Raynal <miquel.raynal@...tlin.com> wrote:

> Right now the driver only has hardware trigger support, which makes use
> of the End Of Conversion (EOC) interrupt by:
> - Enabling the external trigger
> - At completion of the conversion, run a generic handler
> - Push the data to the IIO subsystem by using the triggered buffer
>   infrastructure, which may not only serve this purpose.
> 
> In fact, the interrupt will fire for more reasons than just a hardware
> trigger condition, so make a dedicated interrupt handler which will be
> enhanced by the upcoming changes to handle more situations.
> 
> Signed-off-by: Miquel Raynal <miquel.raynal@...tlin.com>
one suggestion inline.
> ---
>  drivers/iio/adc/max1027.c | 22 ++++++++++++++++++++--
>  1 file changed, 20 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/adc/max1027.c b/drivers/iio/adc/max1027.c
> index 2d6485591761..8d86e77fb5db 100644
> --- a/drivers/iio/adc/max1027.c
> +++ b/drivers/iio/adc/max1027.c
> @@ -472,6 +472,24 @@ static int max1027_read_scan(struct iio_dev *indio_dev)
>  	return 0;
>  }
>  
> +static irqreturn_t max1027_eoc_irq_handler(int irq, void *private)
> +{
> +	struct iio_dev *indio_dev = private;
> +	struct max1027_state *st = iio_priv(indio_dev);
> +	int ret = 0;
> +
> +	if (st->cnvst_trigger) {

I missed this earlier, but it is very similar in purpose to the
logic used in iio_trigger_validate_own_device.  Perhaps you could reuse that
rather than carrying an explicit variable to check for this?

> +		ret = max1027_read_scan(indio_dev);
> +		iio_trigger_notify_done(indio_dev->trig);
> +	}
> +
> +	if (ret)
> +		dev_err(&indio_dev->dev,
> +			"Cannot read scanned values (%d)\n", ret);

Perhaps better to move that into the if statement.  I guess this may
make more sense later though!


> +
> +	return IRQ_HANDLED;
> +}
> +
>  static irqreturn_t max1027_trigger_handler(int irq, void *private)
>  {
>  	struct iio_poll_func *pf = private;
> @@ -563,11 +581,11 @@ static int max1027_probe(struct spi_device *spi)
>  		}
>  
>  		ret = devm_request_threaded_irq(&spi->dev, spi->irq,
> -						iio_trigger_generic_data_rdy_poll,
> +						max1027_eoc_irq_handler,
>  						NULL,
>  						IRQF_TRIGGER_FALLING,
>  						spi->dev.driver->name,
> -						st->trig);
> +						indio_dev);
>  		if (ret < 0) {
>  			dev_err(&indio_dev->dev, "Failed to allocate IRQ.\n");
>  			return ret;