Re: [PATCH v3 0/2] ACPI: Add irq_type to gpio interrupt

[Christophe Ricard <christophe.ricard@gmail.com>]

Hi Mika,


On 01/12/2015 14:03, Mika Westerberg wrote:
[...]
>>     Now for the same kind of i2c driver using acpi description, the GpioInt
>>     polarity/type is at the moment never kept in the irq property.
>>     It is possible to check that following about the same path...
>>     i2c_device_probe (drivers/i2c/i2c-core.c), retrieves irq property from
>>     acpi_dev_gpio_irq_get but does not save the irq_type.
>>     This would allow not to have to use an additional gpio field and all
>>     the configuration step to configure the gpio interrupt correctly in a
>>     device driver and taking a real benefit of the GpioInt acpi keyword
>>     compare to GpioIo keyword.
>>     Most the of the drivers based on acpi description retrieve gpio number
>>     to assign an interrupt and a fix polarity. I believe my patchset
>>     proposal would improve this and allow to
>>     be much closer with devicetree.
>>     Do you see any issue with this ?
> No, but I wonder if it would be better to do this in acpi_dev_gpio_irq_get()
> instead of acpi_find_gpio() which gets called everytime a GPIO is looked up?
I believe, setting the irq type requires triggering and polarity data 
stored into a struct acpi_resource_gpio.

acpi_dev_gpio_irq_get call acpi_get_gpiod_by_index which run acpi_find_gpio.

Actually acpi_dev_gpio_irq_get is called everytime an i2c device slave 
is probed, acpi_find_gpio will get called to "register" gpios.
If done correctly, i think this will be done only once...

The only improvement i may see would be to add an extra field in the 
acpi_gpio_info structure in drivers/gpio/gpiolib.h (for example int 
irq_type).
And call irq_set_irq_type in acpi_dev_gpio_irq_get if the gpio is an 
interrupt.

I guess the current proposal and this one are equivalent...

What do you think ?

Best Regards
Christophe