Re: Question: GPIO driver how to get irq_base

[Lars-Peter Clausen]

On 04/21/2011 09:32 AM, Tomoya MORINAGA wrote:
> Hi GPIO maintainer,
> 
> Need your help.
> I want to add interrupt function to gpio/pch_gpio.c
> 
> According to other upstreamed GPIO driver, (e.g. pl061, langwell, etc...)
> 2 IRQs(irq, irq_base) are used.
> 
> I can get "irq" from (struct pci_dev *)pdev->irq.
> However I can't understand where can I get the "irq_base".
> Let me know how to get.
> 
> Thanks,
> -----------------------------------------
> Tomoya MORINAGA
> OKI SEMICONDUCTOR CO., LTD.

In my opinion the best option for expander chips is to allocate a new irq_desc
range by calling irq_alloc_descs. It will return the first irq number in the
newly allocated range, which will be your irq_base.
But be aware that this will require SPARSE_IRQ to work.

- Lars
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/