linux-kernel - Re: [PATCH 19/21] iio: Use IRQF_NO

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Message-ID: <ac45bbeb-7a76-42f0-88d8-35dbf9742a0c@baylibre.com>
Date: Fri, 23 Jan 2026 14:56:32 -0600
From: David Lechner <dlechner@...libre.com>
To: Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
 linux-kernel@...r.kernel.org
Cc: linux-rt-devel@...ts.linux.dev, Thomas Gleixner <tglx@...nel.org>,
 Jonathan Cameron <jic23@...nel.org>, Nuno Sá
 <nuno.sa@...log.com>, Andy Shevchenko <andy@...nel.org>,
 Lars-Peter Clausen <lars@...afoo.de>,
 Michael Hennerich <Michael.Hennerich@...log.com>, linux-iio@...r.kernel.org
Subject: Re: [PATCH 19/21] iio: Use IRQF_NO_THREAD

On 1/23/26 5:37 AM, Sebastian Andrzej Siewior wrote:
> The interrupt handler iio_trigger_generic_data_rdy_poll() will invoke
> other interrupt handler and this supposed to happen from within the
> hardirq.
> 
> Use IRQF_NO_THREAD to forbid forced-threading.
> 

...

> diff --git a/drivers/iio/adc/ad7766.c b/drivers/iio/adc/ad7766.c
> index 4d570383ef025..9e4a66477d2d0 100644
> --- a/drivers/iio/adc/ad7766.c
> +++ b/drivers/iio/adc/ad7766.c
> @@ -184,12 +184,6 @@ static const struct iio_info ad7766_info = {
>  	.read_raw = &ad7766_read_raw,
>  };
>  
> -static irqreturn_t ad7766_irq(int irq, void *private)
> -{
> -	iio_trigger_poll(private);
> -	return IRQ_HANDLED;
> -}
> -

Replacing this with iio_trigger_generic_data_rdy_poll() seems like a
separate improvement that should be in a separate patch.

At a minimum, the commit message should explain this change. But I expect
the reason will make it obvious it should be a separate patch.

>  static int ad7766_set_trigger_state(struct iio_trigger *trig, bool enable)
>  {
>  	struct ad7766 *ad7766 = iio_trigger_get_drvdata(trig);
> @@ -260,8 +254,8 @@ static int ad7766_probe(struct spi_device *spi)
>  		 * Some platforms might not allow the option to power it down so
>  		 * don't enable the interrupt to avoid extra load on the system
>  		 */
> -		ret = devm_request_irq(&spi->dev, spi->irq, ad7766_irq,
> -				       IRQF_TRIGGER_FALLING | IRQF_NO_AUTOEN,
> +		ret = devm_request_irq(&spi->dev, spi->irq, iio_trigger_generic_data_rdy_poll,
> +				       IRQF_TRIGGER_FALLING | IRQF_NO_AUTOEN | IRQF_NO_THREAD,
>  				       dev_name(&spi->dev),
>  				       ad7766->trig);
>  		if (ret < 0)