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From: David Brownell <david-b@pacbell.net>
To: dmitry pervushin <dpervushin@gmail.com>,
	Rui Sousa <rui.sousa@laposte.net>
Cc: Vitaly Wool <vwool@ru.mvista.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	basicmark@yahoo.com, komal_shah802003@yahoo.com,
	stephen@streetfiresound.com,
	spi-devel-general@lists.sourceforge.net, Joachim_Jaeger@digi.com
Subject: Re: [spi-devel-general] Re: [PATCH 2.6-git 0/4] SPI core refresh
Date: Tue, 13 Dec 2005 08:35:38 -0800	[thread overview]
Message-ID: <200512130835.38754.david-b@pacbell.net> (raw)
In-Reply-To: <1134475765.1590.2.camel@fj-laptop>

> On Mon, 2005-12-12 at 19:01 +0100, Rui Sousa wrote:
> > How do you handle IRQ's generated by a SPI device (e.g ack the
> > interrupt, check if it was the SPI device that generated the
> > interrupt, ...) if you can't read/write on the SPI bus from interrupt
> > context?

I don't understand the question.  The SPI controller may be busy
handling transactions for a different device, so the best you
could do from _any_ IRQ handler is to queue some messages that
will get to the IRQ-issuing device sometime later.  It's not
possible to make the other transactions finish any faster, or
abort them safely mid-transfer.

The way the ads7846 driver handles it, for example, is to issue
a transaction collecting a bunch of touchscreen sensor readings.
And disable its (nonsharable) irq, since the interrupt will be
raised for some time and there's no portable way for Linux to
force the IRQ to trigger only on the relevant edge.

See the 2.6.15-rc5-mm1 patches...

- Dave


  parent reply	other threads:[~2005-12-13 16:37 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-12-12 15:20 [PATCH 2.6-git 0/4] SPI core refresh Vitaly Wool
2005-12-12 15:22 ` [PATCH 2.6-git 1/4] SPI core refresh: SPI core patch Vitaly Wool
2005-12-12 15:49   ` Russell King
2005-12-12 15:24 ` [PATCH 2.6-git 2/4] SPI core refresh: MTD dataflash driver Vitaly Wool
2005-12-12 15:26 ` [PATCH 2.6-git 3/4] SPI core refresh: SPI/PNX controller Vitaly Wool
2005-12-12 15:27 ` [PATCH 2.6-git 4/4] SPI core refresh: dumb EEPROM driver Vitaly Wool
2005-12-12 18:01 ` [PATCH 2.6-git 0/4] SPI core refresh Rui Sousa
2005-12-13 12:09   ` [spi-devel-general] " dmitry pervushin
2005-12-13 15:11     ` Rui Sousa
2005-12-13 17:06       ` dmitry pervushin
2005-12-14  6:57       ` Vitaly Wool
2005-12-14 14:28         ` Rui Sousa
2005-12-13 16:35     ` David Brownell [this message]
2005-12-13 18:02       ` Rui Sousa
2005-12-13 14:06 ` [PATCH/RFC] SPI: add async message handing library to David Brownell's core Vitaly Wool
2005-12-13 16:53   ` [PATCH/RFC] SPI: add DMAUNSAFE analog " Vitaly Wool
2005-12-13 19:01     ` David Brownell
2005-12-13 19:15       ` Greg KH
2005-12-14 13:50         ` Vitaly Wool
2005-12-14 17:18           ` Greg KH
2005-12-14 17:53             ` Vitaly Wool
2005-12-14 18:50               ` [PATCH/RFC] SPI: add DMAUNSAFE analog David Brownell
2005-12-14 19:29                 ` Vitaly Wool
2005-12-14 19:02               ` [PATCH/RFC] SPI: add DMAUNSAFE analog to David Brownell's core David Brownell
2005-12-14 19:19                 ` Vitaly Wool
2005-12-14 19:33                   ` [spi-devel-general] Re: [PATCH/RFC] SPI: add DMAUNSAFE analog David Brownell
2005-12-14 19:34                 ` [PATCH/RFC] SPI: add DMAUNSAFE analog to David Brownell's core Vitaly Wool
2005-12-15  6:47                 ` Vitaly Wool
2005-12-15 16:44                   ` Greg KH
2005-12-15 22:23                     ` Vitaly Wool
2005-12-15 23:02                       ` Greg KH
2005-12-16  8:37                         ` Vitaly Wool
2005-12-16 17:34                           ` Greg KH
2005-12-16 18:32                             ` [spi-devel-general] Re: [PATCH/RFC] SPI: add DMAUNSAFE analog David Brownell
2005-12-15 20:06                   ` David Brownell
2005-12-15 22:17                     ` Vitaly Wool
2005-12-15 22:33                       ` Greg KH
2005-12-16  3:34                         ` Andy Isaacson
2005-12-16  5:17                           ` Greg KH
2005-12-14 19:16               ` [PATCH/RFC] SPI: add DMAUNSAFE analog to David Brownell's core Greg KH
2005-12-14 19:30                 ` Vitaly Wool
2005-12-15 10:00               ` [spi-devel-general] " dmitry pervushin
2005-12-14 17:22           ` David Brownell
2005-12-14 17:50             ` Vitaly Wool
2005-12-14 19:17               ` [PATCH/RFC] SPI: add DMAUNSAFE analog David Brownell
2005-12-14 20:11                 ` Vitaly Wool
2005-12-13 21:47       ` [PATCH/RFC] SPI: add DMAUNSAFE analog to David Brownell's core Vitaly Wool
2005-12-13 22:15       ` Vitaly Wool
2005-12-14 16:55         ` David Brownell
2005-12-14 17:23           ` Vitaly Wool
2005-12-14 18:48   ` [PATCH/RFC] SPI: add async message handing library " Stephen Street
2005-12-14 19:41     ` Vitaly Wool
2005-12-14 21:19       ` Stephen Street
2005-12-14 19:31   ` [PATCH/RFC] SPI: add async message handing library David Brownell
2005-12-15 12:19   ` [PATCH/RFC] SPI: async message handing library update Vitaly Wool
2005-12-18 18:59     ` David Brownell
2005-12-19 15:40       ` [spi-devel-general] " dmitry pervushin
2005-12-20  7:23         ` David Brownell
2005-12-20 18:02       ` Vitaly Wool
2005-12-22 17:28         ` David Brownell
2005-12-22 22:10           ` Vitaly Wool
2005-12-22 23:55             ` David Brownell
2005-12-21 13:17       ` Vitaly Wool

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