linux-kernel - Re: [PATCH v6 3/4] power: supply: twl4030-charger: move irq allocation to just before irqs are enabled

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Message-ID: <20170615114704.odpislk5a4nsigtv@earth>
Date:   Thu, 15 Jun 2017 13:47:04 +0200
From:   Sebastian Reichel <sebastian.reichel@...labora.co.uk>
To:     "H. Nikolaus Schaller" <hns@...delico.com>
Cc:     Grygorii Strashko <grygorii.strashko@...com>,
        NeilBrown <neil@...wn.name>, Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Russell King <linux@...linux.org.uk>,
        Marek Belisko <marek@...delico.com>,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        linux-pm@...r.kernel.org, letux-kernel@...nphoenux.org,
        notasas@...il.com, linux-omap@...r.kernel.org
Subject: Re: [PATCH v6 3/4] power: supply: twl4030-charger: move irq
 allocation to just before irqs are enabled

Hi,

On Wed, Jun 14, 2017 at 11:25:55AM +0200, H. Nikolaus Schaller wrote:
> This avoids a potential race if irqs are enabled and triggered too early
> before the worker is properly set up.
> 
> Suggested-by: Grygorii Strashko <grygorii.strashko@...com>
> Signed-off-by: H. Nikolaus Schaller <hns@...delico.com>
> ---
>  drivers/power/supply/twl4030_charger.c | 28 ++++++++++++++--------------
>  1 file changed, 14 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/power/supply/twl4030_charger.c b/drivers/power/supply/twl4030_charger.c
> index 1fbbe0cc216a..3bebeecb4a1f 100644
> --- a/drivers/power/supply/twl4030_charger.c
> +++ b/drivers/power/supply/twl4030_charger.c
> @@ -984,6 +984,16 @@ static int twl4030_bci_probe(struct platform_device *pdev)
>  
>  	platform_set_drvdata(pdev, bci);
>  
> +	if (bci->dev->of_node) {
> +		struct device_node *phynode;
> +
> +		phynode = of_find_compatible_node(bci->dev->of_node->parent,
> +						  NULL, "ti,twl4030-usb");
> +		if (phynode)
> +			bci->transceiver = devm_usb_get_phy_by_node(
> +				bci->dev, phynode, &bci->usb_nb);
> +	}
> +

The notifier is not that much different from an irq. I see
the call can access at least the iio channel (so iio channel
should be registered first). I suspect worker and power-supply
should also be initialized/registered first. Best location seems
to be directly before requesting the irqs.

>  	bci->channel_vac = devm_iio_channel_get(&pdev->dev, "vac");
>  	if (IS_ERR(bci->channel_vac)) {
>  		bci->channel_vac = NULL;
> @@ -1006,6 +1016,10 @@ static int twl4030_bci_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> +	INIT_WORK(&bci->work, twl4030_bci_usb_work);
> +	INIT_DELAYED_WORK(&bci->current_worker, twl4030_current_worker);
> +
> +	bci->usb_nb.notifier_call = twl4030_bci_usb_ncb;

You should configure the notifier block *before* registering it.

>  	ret = devm_request_threaded_irq(&pdev->dev, bci->irq_chg, NULL,
>  			twl4030_charger_interrupt, IRQF_ONESHOT, pdev->name,
>  			bci);
> @@ -1023,20 +1037,6 @@ static int twl4030_bci_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> -	INIT_WORK(&bci->work, twl4030_bci_usb_work);
> -	INIT_DELAYED_WORK(&bci->current_worker, twl4030_current_worker);
> -
> -	bci->usb_nb.notifier_call = twl4030_bci_usb_ncb;
> -	if (bci->dev->of_node) {
> -		struct device_node *phynode;
> -
> -		phynode = of_find_compatible_node(bci->dev->of_node->parent,
> -						  NULL, "ti,twl4030-usb");
> -		if (phynode)
> -			bci->transceiver = devm_usb_get_phy_by_node(
> -				bci->dev, phynode, &bci->usb_nb);
> -	}
> -
>  	/* Enable interrupts now. */
>  	reg = ~(u32)(TWL4030_ICHGLOW | TWL4030_ICHGEOC | TWL4030_TBATOR2 |
>  		TWL4030_TBATOR1 | TWL4030_BATSTS);

-- Sebastian

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