From: Ned Forrester <nforrester@whoi•edu>
To: David Brownell <david-b@pacbell•net>
Cc: spi-devel-general@lists•sourceforge.net,
Stephen Street <stephen@streetfiresound•com>,
linuxppc-dev@ozlabs•org
Subject: Re: [spi-devel-general] [PATCH 2/3] [SPI] Add new mode: SPI_LOOP
Date: Thu, 26 Jul 2007 23:34:45 -0400 [thread overview]
Message-ID: <46A967D5.30606@whoi.edu> (raw)
In-Reply-To: <200707262007.07537.david-b@pacbell.net>
David Brownell wrote:
> On Thursday 26 July 2007, Anton Vorontsov wrote:
>> Loopback mode is supported by various controllers, this mode
>> is useful for testing, especially in conjunction with spidev
>> driver.
>
> ISTR that Stephen Street provided a loopback mode for debug
> in his pxa2xx_spi code. And I know you're fight that this
> mode shows up in a lot of hardware.
>
> Comments, anyone? This seems like a fair way to expose this
> mechanism. And I tend to agree that it'd mostly be useful in
> conjunction with "spidev".
Yes, it is in pxa2xx_spi. It is passed in a structure that is attached
to spi_board_info.controller_data. I have used it to great effect to
test data modes in the driver for which I have no external hardware
support: various bits/word, clock frequencies, fifo thresholds, dma
burst sizes, etc.
It works for me if this is moved to struct spi_device.
I don't think I have any code that could be readily turned into a
generic test program.
--
Ned Forrester nforrester@whoi•edu
Oceanographic Systems Lab 508-289-2226
Applied Ocean Physics and Engineering Dept.
Woods Hole Oceanographic Institution Woods Hole, MA 02543, USA
http://www.whoi.edu/sbl/liteSite.do?litesiteid=7212
http://www.whoi.edu/hpb/Site.do?id=1532
http://www.whoi.edu/page.do?pid=10079
next prev parent reply other threads:[~2007-07-27 4:03 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-26 13:47 [PATCH 0/3] [SPI] loopback mode support, [POWERPC] loopback mode for spi_mpc83xx Anton Vorontsov
2007-07-26 13:50 ` [PATCH 1/3] [SPI] Sync spidev.{h,c} with spi.h Anton Vorontsov
2007-07-27 3:02 ` [spi-devel-general] [PATCH 1/3] [SPI] Sync spidev.{h, c} " David Brownell
2007-07-26 13:50 ` [PATCH 2/3] [SPI] Add new mode: SPI_LOOP Anton Vorontsov
2007-07-27 3:07 ` [spi-devel-general] " David Brownell
2007-07-27 3:34 ` Ned Forrester [this message]
2007-08-01 18:25 ` David Brownell
2007-07-27 13:27 ` Anton Vorontsov
2007-07-26 13:51 ` [PATCH 3/3] [POWERPC][SPI] spi_mpc83xx: add support for loopback mode Anton Vorontsov
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