Re: [PATCH] irq: fix the interrupt trigger type override issue

[Thomas Gleixner <tglx@linutronix.de>]

Richard!

On Tue, Sep 03 2024 at 15:55, Richard Clark wrote:
> On Mon, Sep 02, 2024 at 04:39:33PM +0200, Thomas Gleixner wrote:
>> So the mapping and the interrupt allocation persist even if nothing uses
>> them. What a waste.
>>
> I checked the code and found that it's not the kernel to create the mapping,
> it's by the driver calling platform_get_irq(...)/of_irq_get(...) to
> create.

:)
 
> Ah, the mapping is created from of_irq_get(...) by driver, the kernel also
> provides the mapping teardown interface - irq_dispose_mapping.
> IMO, the right way for the driver is:
> 	1) driver calls of_irq_get() to get the irq and create the mapping
> 	2) driver *should* call irq_dispose_mapping() as the teardown of step 1.
> 	3) free_irq is the teardown of the request_irq to free the irq and
> 	   its action.

Correct.

Thanks,

        tglx