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Subject: Re: [PATCH v2] uio: fix irq init with dt support & irq not defined
To:     Alexandru Ardelean <alexandru.ardelean@analog.com>,
        linux-kernel@vger.kernel.org
Cc:     gregkh@linuxfoundation.org,
        Dragos Bogdan <dragos.bogdan@analog.com>
References: <20191105072807.14420-1-alexandru.ardelean@analog.com>
 <20191105073212.16719-1-alexandru.ardelean@analog.com>
From:   Damian Hobson-Garcia <dhobsong@igel.co.jp>
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Date:   Wed, 6 Nov 2019 15:41:31 +0900
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On 2019-11-05 4:32 p.m., Alexandru Ardelean wrote:
> This change also does a bit of a unification for the IRQ init code.
> 
> But the actual problem is that UIO_IRQ_NONE == 0, so for the DT case where
> UIO_IRQ_NONE gets assigned to `uioinfo->irq`, a 2nd initialization will get
> triggered (for the IRQ) and this one will exit via `goto bad1`.
> 
> As far as things seem to go, the only case where UIO_IRQ_NONE seems valid,
> is when using a device-tree. The driver has some legacy support for old
> platform_data structures. It looks like, for platform_data a non-existent
> IRQ is an invalid case (or was considered an invalid case).
> Which is why -ENXIO is treated only when a DT is used.
> 
> Signed-off-by: Dragos Bogdan <dragos.bogdan@analog.com>
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
> ---
> 
> Changelog v1 -> v2:
> * removed `int irq` variable ; was omitted when porting the patch to a
>   newer kernel base
> 

This also brings the implementation in line with the what is done in
uio_pdrv_genirq.c

Acked-by: Damian Hobson-Garcia <dhobsong@igel.co.jp>