Re: [PATCH] gpio: sprd: Make irq_chip immutable

[Baolin Wang <baolin.wang@linux.alibaba.com>]

On 12/16/2022 12:17 PM, Cixi Geng wrote:
> From: Cixi Geng <cixi.geng1@unisoc.com>
> 
> Kernel warns about mutable irq_chips:
> 
>      "not an immutable chip, please consider fixing!"
> 
> Make the struct irq_chip const, flag it as IRQCHIP_IMMUTABLE, add the
> new helper functions, and call the appropriate gpiolib functions.

Please split them into 3 patches and each patch converts one driver, 
which is easy to review.

> 
> Signed-off-by: Cixi Geng <cixi.geng1@unisoc.com>
> ---
>   drivers/gpio/gpio-eic-sprd.c      |  4 ++--
>   drivers/gpio/gpio-pmic-eic-sprd.c |  4 ++--
>   drivers/gpio/gpio-sprd.c          | 11 +++++++++--
>   3 files changed, 13 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpio/gpio-eic-sprd.c b/drivers/gpio/gpio-eic-sprd.c
> index 8d722e026e9c..07b9099f2a6d 100644
> --- a/drivers/gpio/gpio-eic-sprd.c
> +++ b/drivers/gpio/gpio-eic-sprd.c
> @@ -631,10 +631,10 @@ static int sprd_eic_probe(struct platform_device *pdev)
>   	sprd_eic->intc.irq_mask = sprd_eic_irq_mask;
>   	sprd_eic->intc.irq_unmask = sprd_eic_irq_unmask;
>   	sprd_eic->intc.irq_set_type = sprd_eic_irq_set_type;
> -	sprd_eic->intc.flags = IRQCHIP_SKIP_SET_WAKE;
> +	sprd_eic->intc.flags = IRQCHIP_SKIP_SET_WAKE | IRQCHIP_IMMUTABLE;
>   
>   	irq = &sprd_eic->chip.irq;
> -	irq->chip = &sprd_eic->intc;
> +	gpio_irq_chip_set_chip(irq, &sprd_eic->intc);
>   	irq->handler = handle_bad_irq;
>   	irq->default_type = IRQ_TYPE_NONE;
>   	irq->parent_handler = sprd_eic_irq_handler;
> diff --git a/drivers/gpio/gpio-pmic-eic-sprd.c b/drivers/gpio/gpio-pmic-eic-sprd.c
> index e518490c4b68..d96604ea10e7 100644
> --- a/drivers/gpio/gpio-pmic-eic-sprd.c
> +++ b/drivers/gpio/gpio-pmic-eic-sprd.c
> @@ -344,10 +344,10 @@ static int sprd_pmic_eic_probe(struct platform_device *pdev)
>   	pmic_eic->intc.irq_set_type = sprd_pmic_eic_irq_set_type;
>   	pmic_eic->intc.irq_bus_lock = sprd_pmic_eic_bus_lock;
>   	pmic_eic->intc.irq_bus_sync_unlock = sprd_pmic_eic_bus_sync_unlock;
> -	pmic_eic->intc.flags = IRQCHIP_SKIP_SET_WAKE;
> +	pmic_eic->intc.flags = IRQCHIP_SKIP_SET_WAKE | IRQCHIP_IMMUTABLE;

Why not add GPIOCHIP_IRQ_RESOURCE_HELPERS for above 2 drivers? Seems we 
can remove the irq_chip from pmic_eic structure, instead we can define 
it statically with adding GPIOCHIP_IRQ_RESOURCE_HELPERS like other patch 
[1] did?

[1] https://lore.kernel.org/all/20220419141846.598305-6-maz@kernel.org/

>   
>   	irq = &pmic_eic->chip.irq;
> -	irq->chip = &pmic_eic->intc;
> +	gpio_irq_chip_set_chip(irq, &pmic_eic->intc);
>   	irq->threaded = true;
>   
>   	ret = devm_gpiochip_add_data(&pdev->dev, &pmic_eic->chip, pmic_eic);
> diff --git a/drivers/gpio/gpio-sprd.c b/drivers/gpio/gpio-sprd.c
> index 9bff63990eee..8398f9707ec0 100644
> --- a/drivers/gpio/gpio-sprd.c
> +++ b/drivers/gpio/gpio-sprd.c
> @@ -64,6 +64,11 @@ static void sprd_gpio_update(struct gpio_chip *chip, unsigned int offset,
>   
>   	writel_relaxed(tmp, base + reg);
>   	spin_unlock_irqrestore(&sprd_gpio->lock, flags);
> +
> +	if (reg == SPRD_GPIO_IE && val == 1)
> +		gpiochip_enable_irq(chip, offset);
> +	else if (reg == SPRD_GPIO_IE && val == 0)
> +		gpiochip_disable_irq(chip, offset);

Looks incorrect to me, IIUC you should move 
gpiochip_enable_irq/gpiochip_disable_irq() into sprd_gpio_irq_mask() and 
sprd_gpio_irq_unmask().

>   }
>   
>   static int sprd_gpio_read(struct gpio_chip *chip, unsigned int offset, u16 reg)
> @@ -205,13 +210,15 @@ static void sprd_gpio_irq_handler(struct irq_desc *desc)
>   	chained_irq_exit(ic, desc);
>   }
>   
> -static struct irq_chip sprd_gpio_irqchip = {
> +static const struct irq_chip sprd_gpio_irqchip = {
>   	.name = "sprd-gpio",
>   	.irq_ack = sprd_gpio_irq_ack,
>   	.irq_mask = sprd_gpio_irq_mask,
>   	.irq_unmask = sprd_gpio_irq_unmask,
>   	.irq_set_type = sprd_gpio_irq_set_type,
>   	.flags = IRQCHIP_SKIP_SET_WAKE,
> +	.flags = IRQCHIP_SKIP_SET_WAKE | IRQCHIP_IMMUTABLE,
> +	GPIOCHIP_IRQ_RESOURCE_HELPERS,
>   };
>   
>   static int sprd_gpio_probe(struct platform_device *pdev)
> @@ -245,7 +252,7 @@ static int sprd_gpio_probe(struct platform_device *pdev)
>   	sprd_gpio->chip.direction_output = sprd_gpio_direction_output;
>   
>   	irq = &sprd_gpio->chip.irq;
> -	irq->chip = &sprd_gpio_irqchip;
> +	gpio_irq_chip_set_chip(irq, &sprd_gpio_irqchip);
>   	irq->handler = handle_bad_irq;
>   	irq->default_type = IRQ_TYPE_NONE;
>   	irq->parent_handler = sprd_gpio_irq_handler;