linux-kernel - Re: [PATCH 2/2] pinctrl: stm32: Add level interrupt support to gpio irq chip

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Date:   Mon, 10 Feb 2020 19:39:02 +0100
From:   Marek Vasut <marex@...x.de>
To:     Alexandre Torgue <alexandre.torgue@...com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Marc Zyngier <marc.zyngier@....com>,
        Linus Walleij <linus.walleij@...aro.org>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-gpio@...r.kernel.org
Subject: Re: [PATCH 2/2] pinctrl: stm32: Add level interrupt support to gpio
 irq chip

On 2/10/20 2:49 PM, Alexandre Torgue wrote:
> This patch adds level interrupt support to gpio irq chip.
> 
> GPIO hardware block is directly linked to EXTI block but EXTI handles
> external interrupts only on edge. To be able to handle GPIO interrupt on
> level a "hack" is done in gpio irq chip: parent interrupt (exti irq chip)
> is retriggered following interrupt type and gpio line value.
> 
> Signed-off-by: Alexandre Torgue <alexandre.torgue@...com>
> 
> diff --git a/drivers/pinctrl/stm32/pinctrl-stm32.c b/drivers/pinctrl/stm32/pinctrl-stm32.c
> index 2d5e0435af0a..04e1b062c20e 100644
> --- a/drivers/pinctrl/stm32/pinctrl-stm32.c
> +++ b/drivers/pinctrl/stm32/pinctrl-stm32.c
> @@ -89,6 +89,7 @@ struct stm32_gpio_bank {
>  	struct pinctrl_gpio_range range;
>  	struct fwnode_handle *fwnode;
>  	struct irq_domain *domain;
> +	u32 irq_type[STM32_GPIO_PINS_PER_BANK];

You might want reverse xmas tree order here.

>  	u32 bank_nr;
>  	u32 bank_ioport_nr;
>  	u32 pin_backup[STM32_GPIO_PINS_PER_BANK];
> @@ -303,6 +304,48 @@ static const struct gpio_chip stm32_gpio_template = {
>  	.get_direction		= stm32_gpio_get_direction,
>  };
>  
> +void stm32_gpio_irq_eoi(struct irq_data *d)
> +{
> +	struct stm32_gpio_bank *bank = d->domain->host_data;
> +	int line;
> +
> +	irq_chip_eoi_parent(d);
> +
> +	/* If level interrupt type then retrig */
> +	line = stm32_gpio_get(&bank->gpio_chip, d->hwirq);
> +	if ((line == 0 && bank->irq_type[d->hwirq] == IRQ_TYPE_LEVEL_LOW) ||
> +	    (line == 1 && bank->irq_type[d->hwirq] == IRQ_TYPE_LEVEL_HIGH))
> +		irq_chip_retrigger_hierarchy(d);
> +};
> +
> +static int stm32_gpio_set_type(struct irq_data *d, unsigned int type)
> +{
> +	struct stm32_gpio_bank *bank = d->domain->host_data;
> +	u32 parent_type;
> +
> +	bank->irq_type[d->hwirq] = type;
> +
> +	switch (type) {
> +	case IRQ_TYPE_EDGE_RISING:
> +	case IRQ_TYPE_EDGE_FALLING:
> +	case IRQ_TYPE_EDGE_BOTH:
> +		parent_type = type;
> +		break;
> +	case IRQ_TYPE_LEVEL_HIGH:
> +		parent_type = IRQ_TYPE_EDGE_RISING;
> +		break;
> +	case IRQ_TYPE_LEVEL_LOW:
> +		parent_type = IRQ_TYPE_EDGE_FALLING;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	irq_chip_set_type_parent(d, parent_type);

irq_chip_set_type_parent() returns error code, shouldn't that be handled?

Otherwise, tested on STM32MP1 with KSZ8851-16MLL NIC.