linux-kernel - Re: [PATCH 5.10 29/76] pinctrl: bcm2835: Change init order for gpio hogs

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Date:   Fri, 31 Dec 2021 10:52:44 +0100
From:   Pavel Machek <pavel@...x.de>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Phil Elwell <phil@...pberrypi.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Sasha Levin <sashal@...nel.org>
Subject: Re: [PATCH 5.10 29/76] pinctrl: bcm2835: Change init order for gpio
 hogs

Hi!

> From: Phil Elwell <phil@...pberrypi.com>
> 
> [ Upstream commit 266423e60ea1b953fcc0cd97f3dad85857e434d1 ]
> 
> ...and gpio-ranges
> 
> pinctrl-bcm2835 is a combined pinctrl/gpio driver. Currently the gpio
> side is registered first, but this breaks gpio hogs (which are
> configured during gpiochip_add_data). Part of the hog initialisation
> is a call to pinctrl_gpio_request, and since the pinctrl driver hasn't
> yet been registered this results in an -EPROBE_DEFER from which it can
> never recover.
> 
> Change the initialisation sequence to register the pinctrl driver
> first.

This does not get error handling right.

> diff --git a/drivers/pinctrl/bcm/pinctrl-bcm2835.c b/drivers/pinctrl/bcm/pinctrl-bcm2835.c
> index 1d21129f7751c..40ce18a0d0190 100644
> --- a/drivers/pinctrl/bcm/pinctrl-bcm2835.c
> +++ b/drivers/pinctrl/bcm/pinctrl-bcm2835.c
> @@ -1244,6 +1244,18 @@ static int bcm2835_pinctrl_probe(struct platform_device *pdev)
>  		raw_spin_lock_init(&pc->irq_lock[i]);
>  	}
>  
> +	pc->pctl_desc = *pdata->pctl_desc;
> +	pc->pctl_dev = devm_pinctrl_register(dev, &pc->pctl_desc, pc);
> +	if (IS_ERR(pc->pctl_dev)) {
> +		gpiochip_remove(&pc->gpio_chip);
> +		return PTR_ERR(pc->pctl_dev);
> +	}

You do gpiochip_remove(), even when it was not added.

> @@ -1251,8 +1263,10 @@ static int bcm2835_pinctrl_probe(struct platform_device *pdev)
>  	girq->parents = devm_kcalloc(dev, BCM2835_NUM_IRQS,
>  				     sizeof(*girq->parents),
>  				     GFP_KERNEL);
> -	if (!girq->parents)
> +	if (!girq->parents) {
> +		pinctrl_remove_gpio_range(pc->pctl_dev, &pc->gpio_range);
>  		return -ENOMEM;
> +	}

And yes, adding the removes here makes sense, but it looks like some
are missing (in 5.10).

Something like this?

Best regards,
								Pavel
diff --git a/drivers/pinctrl/bcm/pinctrl-bcm2835.c b/drivers/pinctrl/bcm/pinctrl-bcm2835.c
index 40ce18a0d019..d605548de7df 100644
--- a/drivers/pinctrl/bcm/pinctrl-bcm2835.c
+++ b/drivers/pinctrl/bcm/pinctrl-bcm2835.c
@@ -1247,7 +1247,6 @@ static int bcm2835_pinctrl_probe(struct platform_device *pdev)
 	pc->pctl_desc = *pdata->pctl_desc;
 	pc->pctl_dev = devm_pinctrl_register(dev, &pc->pctl_desc, pc);
 	if (IS_ERR(pc->pctl_dev)) {
-		gpiochip_remove(&pc->gpio_chip);
 		return PTR_ERR(pc->pctl_dev);
 	}
 
@@ -1264,16 +1263,18 @@ static int bcm2835_pinctrl_probe(struct platform_device *pdev)
 				     sizeof(*girq->parents),
 				     GFP_KERNEL);
 	if (!girq->parents) {
-		pinctrl_remove_gpio_range(pc->pctl_dev, &pc->gpio_range);
-		return -ENOMEM;
+		err = -ENOMEM;
+		goto remove_gpio;
 	}
 
 	if (is_7211) {
 		pc->wake_irq = devm_kcalloc(dev, BCM2835_NUM_IRQS,
 					    sizeof(*pc->wake_irq),
 					    GFP_KERNEL);
-		if (!pc->wake_irq)
-			return -ENOMEM;
+		if (!pc->wake_irq) {
+			err = -ENOMEM;
+			goto remove_gpio;
+		}
 	}
 
 	/*
@@ -1297,8 +1298,10 @@ static int bcm2835_pinctrl_probe(struct platform_device *pdev)
 
 		len = strlen(dev_name(pc->dev)) + 16;
 		name = devm_kzalloc(pc->dev, len, GFP_KERNEL);
-		if (!name)
-			return -ENOMEM;
+		if (!name) {
+			err = -ENOMEM;
+			goto remove_gpio;
+		}
 
 		snprintf(name, len, "%s:bank%d", dev_name(pc->dev), i);
 
@@ -1317,11 +1320,14 @@ static int bcm2835_pinctrl_probe(struct platform_device *pdev)
 	err = gpiochip_add_data(&pc->gpio_chip, pc);
 	if (err) {
 		dev_err(dev, "could not add GPIO chip\n");
-		pinctrl_remove_gpio_range(pc->pctl_dev, &pc->gpio_range);
-		return err;
+		goto remove_gpio;
 	}
 
 	return 0;
+
+remove_gpio:
+	pinctrl_remove_gpio_range(pc->pctl_dev, &pc->gpio_range);
+	return err;
 }
 
 static struct platform_driver bcm2835_pinctrl_driver = {


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HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

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