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Message-ID: <7b9198260805221247t715660d1l4085fe8c310f89c@mail.gmail.com>
Date: Thu, 22 May 2008 20:47:16 +0100
From: "Tom Spink" <tspink@gmail.com>
To: "Hans J. Koch" <hjk@linutronix.de>
Subject: Re: [PATCH 1/1] UIO: Add a write() function to enable/disable interrupts
Cc: linux-kernel@vger.kernel.org, "Greg Kroah-Hartman" <gregkh@suse.de>,
       "Jan Altenberg" <jan.altenberg@linutronix.de>,
       "Thomas Gleixner" <tglx@linutronix.de>,
       "=?ISO-8859-1?Q?Uwe_Kleine-K=C3=B6nig?=" <Uwe.Kleine-Koenig@digi.com>,
       "Magnus Damm" <magnus.damm@gmail.com>
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2008/5/22 Hans J. Koch <hjk@linutronix.de>:
> Sometimes it is necessary to enable/disable the interrupt of a UIO device
> from the userspace part of the driver. With this patch, the UIO kernel driver
> can implement an "irqcontrol()" function that does this. Userspace can write
> an s32 value to /dev/uioX (usually 0 or 1 to turn the irq off or on). The
> UIO core will then call the driver's irqcontrol function.
>
> Signed-off-by: Hans J. Koch <hjk@linutronix.de>

<snip>

Hi,

I wonder if it would be better to implement this as an ioctl, rather
than a write to the device.  Writing to a device is a pretty generic
thing, and this patch would tie that up to specifically controlling
interrupts.  An ioctl would be more appropriate, IMO, as you are
issuing a controlling command, i.e. disable or enable interrupts.

By the way, I have absolutely no idea how the UIO driver works, other
than reading http://lwn.net/Articles/232575/

-- 
Tom Spink