Re: [PATCH] pinctrl: baytrail: Clear direct_irq_en flag on broken configs

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

Hi,

On 1/8/22 10:59, Hans de Goede wrote:
> Hi,
> 
> On 1/8/22 01:04, Andy Shevchenko wrote:
>>
>>
>> On Saturday, January 8, 2022, Hans de Goede <hdegoede@redhat.com <mailto:hdegoede@redhat.com>> wrote:
>>
>>     Some boards set the direct_irq_en flag in the conf0 register without
>>     setting any of the trigger bits. The direct_irq_en flag just means that
>>     the GPIO will send IRQs directly to the APIC instead of going through
>>     the shared interrupt for the GPIO controller, in order for the pin to
>>     be able to actually generate IRQs the trigger flags must still be set.
>>
>>     So having the direct_irq_en flag set without any trigger flags is
>>     non-sense, log a FW_BUG warning when encountering this and clear the flag
>>     so that a driver can actually use the pin as IRQ through gpiod_to_irq().
>>
>>     Specifically this allows the edt-ft5x06 touchscreen driver to use
>>     INT33FC:02 pin 3 as touchscreen IRQ on the Nextbook Ares 8 tablet,
>>     accompanied by the following new log message:
>>
>>     byt_gpio INT33FC:02: [Firmware Bug]: pin 3: direct_irq_en set without trigger, clearing
>>
>>     The new byt_direct_irq_sanity_check() function also checks that the
>>     pin is actually appointed to one of the 16 direct-IRQs which the GPIO
>>     controller supports and on success prints debug messages like these:
>>
>>     byt_gpio INT33FC:02: Pin 0: uses direct IRQ 0 (APIC 67)
>>     byt_gpio INT33FC:02: Pin 15: uses direct IRQ 2 (APIC 69)
>>
>>
>> Should be these updated?
> 
> Yes the " (APIC 6x)" part is gone now. I will fix this for v4.
> 
>>     This is useful to figure out the GPIO pin belonging to ACPI
>>     resources like this one: "Interrupt () { 0x00000043 }" or
>>     the other way around.
>>
>>     Suggested-by: Andy Shevchenko <andy@kernel.org <mailto:andy@kernel.org>>
>>     Signed-off-by: Hans de Goede <hdegoede@redhat.com <mailto:hdegoede@redhat.com>>
>>     ---
>>     Changes in v3:
>>     - Rework code to check if the pin is assigned one of the 16 direct IRQs
>>       (new code suggested-by Andy)
>>     - Drop dev_dbg of the (likely?) APIC IRQ, only log the direct IRQ index
>>
>>
>> Thinking about direct IRQ mappings I will look into the Datasheet next week.
> 
> Ok, I will wait for you to get back to me then before posting a v4.

Note I've found the direct IRQ to IO-APIC pin mappings now, they are
described in: atom-e3800-family-datasheet.pdf, so I've re-added
the APIC IRQ to the printed log msg for v4.

Regards,

Hans