Re: [PATCH v2 1/2] platform/x86: Add x86-acpi-irq-helpers.h

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 12/21/21 16:27, Andy Shevchenko wrote:
> On Tue, Dec 21, 2021 at 5:13 PM Hans de Goede <hdegoede@redhat.com> wrote:
>>
>> Add helper code to get Linux IRQ numbers given a description of the IRQ
>> source (either IOAPIC index, or GPIO chip name + pin-number).
>>
>> This is intended to be used to lookup Linux IRQ numbers in cases where the
>> ACPI description for a device somehow lacks this info. This is only meant
>> for use on x86 ACPI platforms.
>>
>> This code is big/complex enough to warrant sharing, but too small to live
>> in its own module, therefor x86_acpi_irq_helper_get() is defined as
>> a static inline helper function.
> 
> ...
> 
>> +/* For gpio_get_desc which is EXPORT_SYMBOL_GPL() */
> 
> gpio_get_desc()

Fixed in my local version.

> and honestly I don't like this kind of includes (yes,
> I know sometimes it's the best compromise).
> 
>> +#include "../../gpio/gpiolib.h"
> 
> ...
> 
>> +               /* Like acpi_dev_gpio_irq_get(), but without parsing ACPI resources */
>> +               chip = gpiochip_find(data->gpio_chip, x86_acpi_irq_helper_gpiochip_find);
>> +               if (!chip)
>> +                       return -EPROBE_DEFER;
>> +
>> +               gpiod = gpiochip_get_desc(chip, data->index);
>> +               if (IS_ERR(gpiod)) {
>> +                       ret = PTR_ERR(gpiod);
>> +                       pr_err("error %d getting GPIO %s %d\n", ret,
>> +                              data->gpio_chip, data->index);
>> +                       return ret;
>> +               }
>> +
>> +               irq = gpiod_to_irq(gpiod);
>> +               if (irq < 0) {
>> +                       pr_err("error %d getting IRQ %s %d\n", irq,
>> +                              data->gpio_chip, data->index);
>> +                       return irq;
>> +               }
>> +
>> +               irq_type = acpi_dev_get_irq_type(data->trigger, data->polarity);
>> +               if (irq_type != IRQ_TYPE_NONE && irq_type != irq_get_trigger_type(irq))
>> +                       irq_set_irq_type(irq, irq_type);
>> +
>> +               return irq;
> 
> I'm wondering why it can't be a part of the GPIO ACPI library?

Interesting suggestion, but this really is only intended for the
special case when the DSDT is missing this info. I'm a bit worried
that having this available as a generic helper may lead to it
getting used too much. But I guess we can just put a comment on it
explaining that normally its use should be avoided.

I've added Mika to the Cc, Mika, what do you think about adding this
as a new helper to the GPIO ACPI library ?

Regards,

Hans