From: Frank Pagliughi <fpagliughi@mindspring.com>
To: Frank Pagliughi <frank@sorosys.com>,
eCos Discussion <ecos-discuss@ecos.sourceware.org>
Subject: Re: [ECOS] Device driver open & close
Date: Wed, 27 Aug 2008 05:22:00 -0000 [thread overview]
Message-ID: <48B47309.8090608@mindspring.com> (raw)
In-Reply-To: <48B4601F.5010607@mindspring.com>
Frank Pagliughi wrote:
>
>
> Andrew Lunn wrote:
>> On Mon, Aug 25, 2008 at 07:31:09PM -0400, Frank Pagliughi wrote:
>>
>>> Hey All,
>>>
>>> Is there a mechanism by which a device driver can be notified when
>>> the application opens or closes the device. For example, I have an
>>> LCD in my system, and I would like to turn it on when the
>>> application opens the device and turn it off when it gets closed.
>>> Then turn it back on again if it gets re-opened, etc.
>>>
>>
>> open() should result in the lookup function being called on the
>> device.
>>
> This gets called for each open?
>> Close is a problem, since there is no device close function.
>>
>> You might be better using cyg_io_set_config() mechanism to turn it on
>> and off.
>>
> This is unfortunate. For another example, the system will have the
> ability to power down the compact flash drive(s). Which order should
> the power down happen?
> flush() the buffers, then cyg_io_set_config() to power down the
> drive, *then* close() ? I assume you can't use the handle to
> set_config after the close(). Right?
>
Oh, sorry, the disk drive is a bad example, and a whole different
problem, I suppose. Maybe a drive can power up/down when its filesystem
is mounted/unmounted?
I'm just doing the OS port & device drivers for a board that has to
really conserve power and thus turn devices off and on a lot. Someone
else will write the application, so I'm trying to make the interface as
simple and familiar as possible (therefore standard I/O api). It seems
that the eCos device API assumes that devices will be initialized then
stay on forever. So, any ideas are appreciated.
Thanks,
Frank
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next prev parent reply other threads:[~2008-08-26 21:20 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-26 4:49 Frank Pagliughi
2008-08-26 15:28 ` Andrew Lunn
2008-08-26 21:20 ` Frank Pagliughi
2008-08-27 5:22 ` Frank Pagliughi [this message]
2008-08-27 7:12 ` Andrew Lunn
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