linux-kernel - Re: [PATCH v2 2/2] pinctrl: stm32: Add level interrupt support to gpio irq chip

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Date:   Wed, 19 Feb 2020 12:07:15 +0000
From:   Marc Zyngier <maz@...nel.org>
To:     Alexandre Torgue <alexandre.torgue@...com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Linus Walleij <linus.walleij@...aro.org>, marex@...x.de,
        linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 2/2] pinctrl: stm32: Add level interrupt support to
 gpio irq chip

On 2020-02-19 11:34, Alexandre Torgue wrote:
> Fix Marc email address.
> 
> On 2/18/20 2:12 PM, Alexandre Torgue wrote:
>> This patch adds level interrupt support to gpio irq chip.

A commit message should not contain "this patch".

>> 
>> 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>
>> Tested-by: Marek Vasut <marex@...x.de>
>> 
>> diff --git a/drivers/pinctrl/stm32/pinctrl-stm32.c 
>> b/drivers/pinctrl/stm32/pinctrl-stm32.c
>> index 2d5e0435af0a..dae236562543 100644
>> --- a/drivers/pinctrl/stm32/pinctrl-stm32.c
>> +++ b/drivers/pinctrl/stm32/pinctrl-stm32.c
>> @@ -92,6 +92,7 @@ struct stm32_gpio_bank {
>>   	u32 bank_nr;
>>   	u32 bank_ioport_nr;
>>   	u32 pin_backup[STM32_GPIO_PINS_PER_BANK];
>> +	u32 irq_type[STM32_GPIO_PINS_PER_BANK];

Do you really need a u32 here? an array of u8 seems enough. After all,
you only need two bits of information per interrupts (level or not,
low or high).

>>   };
>>     struct stm32_pinctrl {
>> @@ -303,6 +304,46 @@ 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);

s/line/level/

>> +};
>> +
>> +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;

It would make more sense if this this assignment was done *after*
sanitizing the type value.

>> +
>> +	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;
>> +	}
>> +
>> +	return irq_chip_set_type_parent(d, parent_type);
>> +};
>> +
>>   static int stm32_gpio_irq_request_resources(struct irq_data 
>> *irq_data)
>>   {
>>   	struct stm32_gpio_bank *bank = irq_data->domain->host_data;
>> @@ -332,11 +373,11 @@ static void 
>> stm32_gpio_irq_release_resources(struct irq_data *irq_data)
>>     static struct irq_chip stm32_gpio_irq_chip = {
>>   	.name		= "stm32gpio",
>> -	.irq_eoi	= irq_chip_eoi_parent,
>> +	.irq_eoi	= stm32_gpio_irq_eoi,
>>   	.irq_ack	= irq_chip_ack_parent,
>>   	.irq_mask	= irq_chip_mask_parent,
>>   	.irq_unmask	= irq_chip_unmask_parent,
>> -	.irq_set_type	= irq_chip_set_type_parent,
>> +	.irq_set_type	= stm32_gpio_set_type,
>>   	.irq_set_wake	= irq_chip_set_wake_parent,
>>   	.irq_request_resources = stm32_gpio_irq_request_resources,
>>   	.irq_release_resources = stm32_gpio_irq_release_resources,
>> 

Thanks,

         M.
-- 
Jazz is not dead. It just smells funny...