linux-kernel - Re: [RFT PATCH 4/9] usb: typec: tipd: Add short-circuit for no irqs

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Message-ID: <YUnctHnzHHEJgp2m@kuha.fi.intel.com>
Date:   Tue, 21 Sep 2021 16:23:00 +0300
From:   Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To:     Sven Peter <sven@...npeter.dev>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Guido Günther <agx@...xcpu.org>,
        Bryan O'Donoghue <bryan.odonoghue@...aro.org>,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        Hector Martin <marcan@...can.st>,
        Mohamed Mediouni <mohamed.mediouni@...amail.com>,
        Stan Skowronek <stan@...ellium.com>,
        Mark Kettenis <mark.kettenis@...all.nl>,
        Alexander Graf <graf@...zon.com>,
        Alyssa Rosenzweig <alyssa@...enzweig.io>
Subject: Re: [RFT PATCH 4/9] usb: typec: tipd: Add short-circuit for no irqs

On Sat, Sep 18, 2021 at 02:09:29PM +0200, Sven Peter wrote:
> If no interrupts are set in IntEventX directly skip to the end of the
> interrupt handler and return IRQ_NONE instead of IRQ_HANDLED.
> This possibly allows to detect spurious interrupts if the i2c bus is fast
> enough.
> 
> Signed-off-by: Sven Peter <sven@...npeter.dev>

Reviewed-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>

> ---
>  drivers/usb/typec/tipd/core.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/typec/tipd/core.c b/drivers/usb/typec/tipd/core.c
> index c2c399722c37..4a6d66250fef 100644
> --- a/drivers/usb/typec/tipd/core.c
> +++ b/drivers/usb/typec/tipd/core.c
> @@ -434,6 +434,8 @@ static irqreturn_t tps6598x_interrupt(int irq, void *data)
>  	trace_tps6598x_irq(event1, event2);
>  
>  	event = event1 | event2;
> +	if (!event)
> +		goto err_unlock;
>  
>  	ret = tps6598x_read32(tps, TPS_REG_STATUS, &status);
>  	if (ret) {
> @@ -481,7 +483,9 @@ static irqreturn_t tps6598x_interrupt(int irq, void *data)
>  err_unlock:
>  	mutex_unlock(&tps->lock);
>  
> -	return IRQ_HANDLED;
> +	if (event)
> +		return IRQ_HANDLED;
> +	return IRQ_NONE;
>  }
>  
>  static int tps6598x_check_mode(struct tps6598x *tps)
> -- 
> 2.25.1

thanks,

-- 
heikki