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From: Marc Pignat <marc.pignat-7TsPiqsLilE@public.gmane.org>
To: Atsushi Nemoto <anemo-7JcRY8pycbNHfZP73Gtkiw@public.gmane.org>
Cc: david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org,
	spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH] atmel_spi: support zero length transfer
Date: Thu, 21 Feb 2008 10:26:16 +0100	[thread overview]
Message-ID: <200802211026.17816.marc.pignat@hevs.ch> (raw)
In-Reply-To: <20080221.105233.41199605.nemoto-IGagC74glE2asRnM1LW+pc8NsWr+9BEh@public.gmane.org>

Hi!

On Thursday 21 February 2008, Atsushi Nemoto wrote:
...
> Yes.  I tested it on AT91SAM9260 and it seems ENDRX rises soon.
> Though it can be possible to avoid starting DMA for zero length
> transfer, I think it is not worth to optimize for such a rare case.
Ok, verified to work on at91rm9200, should be tested on AVR32.

David, do you think writing 0 bytes is a valid use of this API?
IMHO, we should add a fied to the spi_transfer struct.

Regards

Marc


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WARNING: multiple messages have this Message-ID (diff)
From: Marc Pignat <marc.pignat@hevs.ch>
To: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: hskinnemoen@atmel.com, david-b@pacbell.net,
	spi-devel-general@lists.sourceforge.net,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] atmel_spi: support zero length transfer
Date: Thu, 21 Feb 2008 10:26:16 +0100	[thread overview]
Message-ID: <200802211026.17816.marc.pignat@hevs.ch> (raw)
In-Reply-To: <20080221.105233.41199605.nemoto@toshiba-tops.co.jp>

Hi!

On Thursday 21 February 2008, Atsushi Nemoto wrote:
...
> Yes.  I tested it on AT91SAM9260 and it seems ENDRX rises soon.
> Though it can be possible to avoid starting DMA for zero length
> transfer, I think it is not worth to optimize for such a rare case.
Ok, verified to work on at91rm9200, should be tested on AVR32.

David, do you think writing 0 bytes is a valid use of this API?
IMHO, we should add a fied to the spi_transfer struct.

Regards

Marc


  parent reply	other threads:[~2008-02-21  9:26 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-20 15:54 [PATCH] atmel_spi: support zero length transfer Atsushi Nemoto
2008-02-20 15:54 ` Atsushi Nemoto
     [not found] ` <20080221.005432.07645461.anemo-7JcRY8pycbNHfZP73Gtkiw@public.gmane.org>
2008-02-20 17:55   ` Marc Pignat
2008-02-20 17:55     ` Marc Pignat
     [not found]     ` <200802201855.02605.marc.pignat-7TsPiqsLilE@public.gmane.org>
2008-02-21  1:52       ` Atsushi Nemoto
2008-02-21  1:52         ` Atsushi Nemoto
     [not found]         ` <20080221.105233.41199605.nemoto-IGagC74glE2asRnM1LW+pc8NsWr+9BEh@public.gmane.org>
2008-02-21  9:26           ` Marc Pignat [this message]
2008-02-21  9:26             ` Marc Pignat
2008-02-21 19:23             ` David Brownell
     [not found]               ` <20080221192334.EE97A230A58-ZcXrCSuhvln6VZ3dlLfH/g4gEjPzgfUyLrfjE7I9kuVHxeISYlDBzl6hYfS7NtTn@public.gmane.org>
2008-02-22  9:30                 ` Marc Pignat
2008-02-22  9:30                   ` Marc Pignat
     [not found]                   ` <200802221030.32263.marc.pignat-7TsPiqsLilE@public.gmane.org>
2008-02-22 14:15                     ` Atsushi Nemoto
2008-02-22 14:15                       ` Atsushi Nemoto
     [not found]                       ` <20080222.231510.56565462.anemo-7JcRY8pycbNHfZP73Gtkiw@public.gmane.org>
2008-02-22 14:28                         ` Ned Forrester
2008-02-22 14:28                           ` [spi-devel-general] " Ned Forrester
2008-02-22 19:06                           ` David Brownell
     [not found]                             ` <20080222190613.0043B229B4D-ZcXrCSuhvln6VZ3dlLfH/g4gEjPzgfUyLrfjE7I9kuVHxeISYlDBzl6hYfS7NtTn@public.gmane.org>
2008-02-22 19:52                               ` Ned Forrester
2008-02-22 19:52                                 ` [spi-devel-general] " Ned Forrester
2008-02-22 18:58                         ` David Brownell
2008-02-22 18:58                           ` [spi-devel-general] " David Brownell
2008-02-23  2:55                     ` David Brownell
2008-02-23  2:55                       ` David Brownell
     [not found]                       ` <200802221855.25892.david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
2008-02-25  8:15                         ` Marc Pignat
2008-02-25  8:15                           ` Marc Pignat
2008-02-22 14:07                 ` Ned Forrester
2008-02-22 14:07                   ` [spi-devel-general] " Ned Forrester
2008-02-22 19:02                   ` David Brownell
     [not found]                     ` <20080222190228.2B0CB28E363-ZcXrCSuhvln6VZ3dlLfH/g4gEjPzgfUyLrfjE7I9kuVHxeISYlDBzl6hYfS7NtTn@public.gmane.org>
2008-02-22 19:36                       ` Ned Forrester
2008-02-22 19:36                         ` [spi-devel-general] " Ned Forrester
     [not found]                         ` <47BF2455.8030904-/d+BM93fTQY@public.gmane.org>
2008-02-23  2:37                           ` David Brownell
2008-02-23  2:37                             ` [spi-devel-general] " David Brownell
2008-02-25  0:25                           ` Atsushi Nemoto
2008-02-25  0:25                             ` [spi-devel-general] " Atsushi Nemoto

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