Re: [PATCH v4 07/10] iio: imu: adis_trigger: Allow level interrupts for FIFO readings

["Nuno Sá" <noname.nuno@gmail.com>]

On Fri, 2024-05-24 at 12:00 +0300, Ramona Gradinariu wrote:
> Currently, adis library allows configuration only for edge interrupts,
> needed for data ready sampling.
> This patch removes the restriction for level interrupts for devices
> which have FIFO support.
> Furthermore, in case of devices which have FIFO support,
> devm_request_threaded_irq is used for interrupt allocation, to avoid
> flooding the processor with the FIFO watermark level interrupt, which
> is active until enough data has been read from the FIFO.
> 
> Signed-off-by: Ramona Gradinariu <ramona.bolboaca13@gmail.com>
> ---

Reviewed-by: Nuno Sa <nuno.sa@analog.com>
(much better, IMO, commit message :))

>  drivers/iio/imu/adis_trigger.c | 37 ++++++++++++++++++++++++----------
>  include/linux/iio/imu/adis.h   |  1 +
>  2 files changed, 27 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/iio/imu/adis_trigger.c b/drivers/iio/imu/adis_trigger.c
> index f890bf842db8..a8740b043cfe 100644
> --- a/drivers/iio/imu/adis_trigger.c
> +++ b/drivers/iio/imu/adis_trigger.c
> @@ -34,17 +34,24 @@ static int adis_validate_irq_flag(struct adis *adis)
>  	if (adis->data->unmasked_drdy)
>  		adis->irq_flag |= IRQF_NO_AUTOEN;
>  	/*
> -	 * Typically this devices have data ready either on the rising edge or
> -	 * on the falling edge of the data ready pin. This checks enforces that
> -	 * one of those is set in the drivers... It defaults to
> -	 * IRQF_TRIGGER_RISING for backward compatibility with devices that
> -	 * don't support changing the pin polarity.
> +	 * Typically adis devices without FIFO have data ready either on the
> +	 * rising edge or on the falling edge of the data ready pin.
> +	 * IMU devices with FIFO support have the watermark pin level driven
> +	 * either high or low when the FIFO is filled with the desired number
> +	 * of samples.
> +	 * It defaults to IRQF_TRIGGER_RISING for backward compatibility with
> +	 * devices that don't support changing the pin polarity.
>  	 */
>  	if (direction == IRQF_TRIGGER_NONE) {
>  		adis->irq_flag |= IRQF_TRIGGER_RISING;
>  		return 0;
>  	} else if (direction != IRQF_TRIGGER_RISING &&
> -		   direction != IRQF_TRIGGER_FALLING) {
> +		   direction != IRQF_TRIGGER_FALLING && !adis->data->has_fifo) {
> +		dev_err(&adis->spi->dev, "Invalid IRQ mask: %08lx\n",
> +			adis->irq_flag);
> +		return -EINVAL;
> +	} else if (direction != IRQF_TRIGGER_HIGH &&
> +		   direction != IRQF_TRIGGER_LOW && adis->data->has_fifo) {
>  		dev_err(&adis->spi->dev, "Invalid IRQ mask: %08lx\n",
>  			adis->irq_flag);
>  		return -EINVAL;
> @@ -77,11 +84,19 @@ int devm_adis_probe_trigger(struct adis *adis, struct iio_dev
> *indio_dev)
>  	if (ret)
>  		return ret;
>  
> -	ret = devm_request_irq(&adis->spi->dev, adis->spi->irq,
> -			       &iio_trigger_generic_data_rdy_poll,
> -			       adis->irq_flag,
> -			       indio_dev->name,
> -			       adis->trig);
> +	if (adis->data->has_fifo)
> +		ret = devm_request_threaded_irq(&adis->spi->dev, adis->spi->irq,
> +						NULL,
> +						&iio_trigger_generic_data_rdy_poll
> ,
> +						adis->irq_flag | IRQF_ONESHOT,
> +						indio_dev->name,
> +						adis->trig);
> +	else
> +		ret = devm_request_irq(&adis->spi->dev, adis->spi->irq,
> +				       &iio_trigger_generic_data_rdy_poll,
> +				       adis->irq_flag,
> +				       indio_dev->name,
> +				       adis->trig);
>  	if (ret)
>  		return ret;
>  
> diff --git a/include/linux/iio/imu/adis.h b/include/linux/iio/imu/adis.h
> index 8dda3cfa5773..4d4cdbe155b2 100644
> --- a/include/linux/iio/imu/adis.h
> +++ b/include/linux/iio/imu/adis.h
> @@ -85,6 +85,7 @@ struct adis_data {
>  	bool unmasked_drdy;
>  
>  	bool has_paging;
> +	bool has_fifo;
>  
>  	unsigned int burst_reg_cmd;
>  	unsigned int burst_len;