Re: [PATCH] gpio: pca953x: Use irqchip template

[Nikhil Devshatwar <nikhil.nd@xxxxxx>]

On 16:40-20200717, Linus Walleij wrote:
> This makes the driver use the irqchip template to assign
> properties to the gpio_irq_chip instead of using the
> explicit calls to gpiochip_irqchip_add_nested() and
> gpiochip_set_nested_irqchip(). The irqchip is instead
> added while adding the gpiochip.
> 
> Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Cc: Marek Vasut <marek.vasut@xxxxxxxxx>
> Cc: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
> Cc: Adam Ford <aford173@xxxxxxxxx>
> Cc: Vignesh Raghavendra <vigneshr@xxxxxx>
> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>

Hi,
I am getting a kernel crash on K3 j721e common processor board
when HDMI is plugged in. Following is the full log with crash
for NULL pointer derefence

https://pastebin.ubuntu.com/p/wBPS2ymmqR/

Upon inspection, I found that the "irq_find_mapping" call
in the "pca953x_irq_handler" returns 0 and the same is passed
to "handle_nested_irq"


> ---
>  drivers/gpio/gpio-pca953x.c | 25 +++++++++++++------------
>  1 file changed, 13 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
> index 9c90cf3aac5a..ab22152bf3e8 100644
> --- a/drivers/gpio/gpio-pca953x.c
> +++ b/drivers/gpio/gpio-pca953x.c
> @@ -834,6 +834,7 @@ static int pca953x_irq_setup(struct pca953x_chip *chip, int irq_base)
>  	struct irq_chip *irq_chip = &chip->irq_chip;
>  	DECLARE_BITMAP(reg_direction, MAX_LINE);
>  	DECLARE_BITMAP(irq_stat, MAX_LINE);
> +	struct gpio_irq_chip *girq;
>  	int ret;
>  
>  	if (dmi_first_match(pca953x_dmi_acpi_irq_info)) {
> @@ -883,16 +884,16 @@ static int pca953x_irq_setup(struct pca953x_chip *chip, int irq_base)
>  	irq_chip->irq_set_type = pca953x_irq_set_type;
>  	irq_chip->irq_shutdown = pca953x_irq_shutdown;
>  
> -	ret = gpiochip_irqchip_add_nested(&chip->gpio_chip, irq_chip,
> -					  irq_base, handle_simple_irq,
> -					  IRQ_TYPE_NONE);
> -	if (ret) {
> -		dev_err(&client->dev,
> -			"could not connect irqchip to gpiochip\n");
> -		return ret;
> -	}
> -
> -	gpiochip_set_nested_irqchip(&chip->gpio_chip, irq_chip, client->irq);
> +	girq = &chip->gpio_chip.irq;
> +	girq->chip = irq_chip;
> +	/* This will let us handle the parent IRQ in the driver */
> +	girq->parent_handler = NULL;
> +	girq->num_parents = 0;
> +	girq->parents = NULL;
> +	girq->default_type = IRQ_TYPE_NONE;
> +	girq->handler = handle_simple_irq;
> +	girq->threaded = true;
> +	girq->first = irq_base; /* FIXME: get rid of this */
>  
>  	return 0;
>  }
> @@ -1080,11 +1081,11 @@ static int pca953x_probe(struct i2c_client *client,
>  	if (ret)
>  		goto err_exit;
>  
> -	ret = devm_gpiochip_add_data(&client->dev, &chip->gpio_chip, chip);
> +	ret = pca953x_irq_setup(chip, irq_base);
>  	if (ret)
>  		goto err_exit;
>  
> -	ret = pca953x_irq_setup(chip, irq_base);
> +	ret = devm_gpiochip_add_data(&client->dev, &chip->gpio_chip, chip);
>  	if (ret)
>  		goto err_exit;
>  
> -- 
> 2.26.2
>