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From: jacmet@sunsite.dk (Peter Korsgaard)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] at91sam9g45: fix i2c bus speed
Date: Thu, 23 Sep 2010 12:21:14 +0200	[thread overview]
Message-ID: <87fwx0ahgl.fsf@macbook.be.48ers.dk> (raw)
In-Reply-To: <20100923093104.GA22397@n2100.arm.linux.org.uk> (Russell King's message of "Thu, 23 Sep 2010 10:31:04 +0100")

>>>>> "Russell" == Russell King <- ARM Linux <linux@arm.linux.org.uk>> writes:

Hi,

 Russell> udelay(5) should always give something approximating a 5us
 Russell> delay, as we calibrate this delay loop against the system
 Russell> timer.  What I could believe is probably going on here is that
 Russell> writing to the hardware is adding additional delays - but
 Russell> that's nothing to do with the CPU speed itself.

Well, the gpio handling (sw) overhead is to a certain degree related to
the CPU speed.

-- 
Bye, Peter Korsgaard

  parent reply	other threads:[~2010-09-23 10:21 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-22  9:31 [PATCH] at91sam9g45: fix i2c bus speed Peter Korsgaard
2010-09-22 10:48 ` Jean-Christophe PLAGNIOL-VILLARD
2010-09-22 11:08   ` Peter Korsgaard
2010-09-22 14:34     ` Jean-Christophe PLAGNIOL-VILLARD
2010-09-22 14:54       ` Wolfgang Wegner
2010-09-22 16:09         ` Jean-Christophe PLAGNIOL-VILLARD
2010-09-22 15:18       ` Peter Korsgaard
2010-09-22 16:05         ` Nicolas Ferre
2010-09-22 16:10         ` Jean-Christophe PLAGNIOL-VILLARD
2010-09-22 16:06 ` Nicolas Ferre
2010-09-23  8:18 ` Nicolas Ferre
2010-09-23  9:22   ` Peter Korsgaard
2010-09-23  9:31     ` Russell King - ARM Linux
2010-09-23 10:09       ` Jean-Christophe PLAGNIOL-VILLARD
2010-09-23 10:24         ` Peter Korsgaard
2010-09-23 10:21       ` Peter Korsgaard [this message]
2010-09-23 10:36         ` Russell King - ARM Linux
2010-09-23 10:54           ` Peter Korsgaard
2010-09-23 11:16             ` Jean-Christophe PLAGNIOL-VILLARD
2010-09-23 11:32               ` Peter Korsgaard
2010-09-23 12:00                 ` Jean-Christophe PLAGNIOL-VILLARD
2010-09-23 11:07           ` Jean-Christophe PLAGNIOL-VILLARD

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