Re: [PATCH v2] gpio: dwapb: Make the irqchip immutable

[Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx>]

On 5/20/22 19:23, Geert Uytterhoeven wrote:
> Commit 6c846d026d49 ("gpio: Don't fiddle with irqchips marked as
> immutable") added a warning to indicate if the gpiolib is altering the
> internals of irqchips.  Following this change the following warning is
> now observed for the dwapb driver:
> 
>     gpio gpiochip0: (50200000.gpio): not an immutable chip, please consider fixing it!
> 
> Fix this by making the irqchip in the dwapb driver immutable.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> ---
> Against gpio/for-next.
> Boot-tested on SiPEED MAiXBiT (Canaan K210).

FYI, fully fixed userspace is available here:

git@xxxxxxxxxx:damien-lemoal/buildroot.git
branch: k210-v16

Need some patch commit message cleanup and I will post that to buildroot list.

> 
> v2:
>   - Factor out hwirq using preferred helper.
> ---
>  drivers/gpio/gpio-dwapb.c | 38 ++++++++++++++++++++++++--------------
>  1 file changed, 24 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpio/gpio-dwapb.c b/drivers/gpio/gpio-dwapb.c
> index 7130195da48d75dd..04afe728e18748df 100644
> --- a/drivers/gpio/gpio-dwapb.c
> +++ b/drivers/gpio/gpio-dwapb.c
> @@ -95,7 +95,6 @@ struct dwapb_context {
>  #endif
>  
>  struct dwapb_gpio_port_irqchip {
> -	struct irq_chip		irqchip;
>  	unsigned int		nr_irqs;
>  	unsigned int		irq[DWAPB_MAX_GPIOS];
>  };
> @@ -252,24 +251,30 @@ static void dwapb_irq_mask(struct irq_data *d)
>  {
>  	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
>  	struct dwapb_gpio *gpio = to_dwapb_gpio(gc);
> +	irq_hw_number_t hwirq = irqd_to_hwirq(d);
>  	unsigned long flags;
>  	u32 val;
>  
>  	raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
> -	val = dwapb_read(gpio, GPIO_INTMASK) | BIT(irqd_to_hwirq(d));
> +	val = dwapb_read(gpio, GPIO_INTMASK) | BIT(hwirq);
>  	dwapb_write(gpio, GPIO_INTMASK, val);
>  	raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
> +
> +	gpiochip_disable_irq(gc, hwirq);
>  }
>  
>  static void dwapb_irq_unmask(struct irq_data *d)
>  {
>  	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
>  	struct dwapb_gpio *gpio = to_dwapb_gpio(gc);
> +	irq_hw_number_t hwirq = irqd_to_hwirq(d);
>  	unsigned long flags;
>  	u32 val;
>  
> +	gpiochip_enable_irq(gc, hwirq);
> +
>  	raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
> -	val = dwapb_read(gpio, GPIO_INTMASK) & ~BIT(irqd_to_hwirq(d));
> +	val = dwapb_read(gpio, GPIO_INTMASK) & ~BIT(hwirq);
>  	dwapb_write(gpio, GPIO_INTMASK, val);
>  	raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
>  }
> @@ -364,8 +369,23 @@ static int dwapb_irq_set_wake(struct irq_data *d, unsigned int enable)
>  
>  	return 0;
>  }
> +#else
> +#define dwapb_irq_set_wake	NULL
>  #endif
>  
> +static const struct irq_chip dwapb_irq_chip = {
> +	.name		= DWAPB_DRIVER_NAME,
> +	.irq_ack	= dwapb_irq_ack,
> +	.irq_mask	= dwapb_irq_mask,
> +	.irq_unmask	= dwapb_irq_unmask,
> +	.irq_set_type	= dwapb_irq_set_type,
> +	.irq_enable	= dwapb_irq_enable,
> +	.irq_disable	= dwapb_irq_disable,
> +	.irq_set_wake	= dwapb_irq_set_wake,
> +	.flags		= IRQCHIP_IMMUTABLE,
> +	GPIOCHIP_IRQ_RESOURCE_HELPERS,
> +};
> +
>  static int dwapb_gpio_set_debounce(struct gpio_chip *gc,
>  				   unsigned offset, unsigned debounce)
>  {
> @@ -439,16 +459,6 @@ static void dwapb_configure_irqs(struct dwapb_gpio *gpio,
>  	girq->default_type = IRQ_TYPE_NONE;
>  
>  	port->pirq = pirq;
> -	pirq->irqchip.name = DWAPB_DRIVER_NAME;
> -	pirq->irqchip.irq_ack = dwapb_irq_ack;
> -	pirq->irqchip.irq_mask = dwapb_irq_mask;
> -	pirq->irqchip.irq_unmask = dwapb_irq_unmask;
> -	pirq->irqchip.irq_set_type = dwapb_irq_set_type;
> -	pirq->irqchip.irq_enable = dwapb_irq_enable;
> -	pirq->irqchip.irq_disable = dwapb_irq_disable;
> -#ifdef CONFIG_PM_SLEEP
> -	pirq->irqchip.irq_set_wake = dwapb_irq_set_wake;
> -#endif
>  
>  	/*
>  	 * Intel ACPI-based platforms mostly have the DesignWare APB GPIO
> @@ -475,7 +485,7 @@ static void dwapb_configure_irqs(struct dwapb_gpio *gpio,
>  		girq->parent_handler = dwapb_irq_handler;
>  	}
>  
> -	girq->chip = &pirq->irqchip;
> +	gpio_irq_chip_set_chip(girq, &dwapb_irq_chip);
>  
>  	return;
>  

Looks OK to me.

Reviewed-by: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx>

-- 
Damien Le Moal
Western Digital Research