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

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Message-ID: <2ac7037f-a29e-afb2-ef6d-27eac9817e3c@st.com>
Date:   Wed, 19 Feb 2020 13:59:09 +0100
From:   Alexandre Torgue <alexandre.torgue@...com>
To:     Marc Zyngier <maz@...nel.org>
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

Hi Marc

On 2/19/20 1:07 PM, Marc Zyngier wrote:
> 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".

Ok I'll change in v3

> 
>>>
>>> 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).

I agree. No need to have u32.

> 
>>>   };
>>>     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/
> 

correct

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

Ok.

> 
>>> +
>>> +    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.