From: Timur Tabi <timur@freescale.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] fsl_i2c: increase I2C timeout values and make them configurable
Date: Thu, 10 Sep 2009 08:07:36 -0500 [thread overview]
Message-ID: <4AA8FA18.20103@freescale.com> (raw)
In-Reply-To: <OF50645EAC.EE2D33E5-ONC125762D.002C17DA-C125762D.002D6101@transmode.se>
Joakim Tjernlund wrote:
> BTW, the fdr and dfsr calculations appears totally bogus. It seems
> like the table is taken from some examples in AN2919 and it is pure luck
> that it works most of the time. For me it does not work 100%, instead I get
> random errors which hangs both the controller and the RTC device.
Well, the problem is that for a given frequency, there are several values of fdr/dfsr that theoretically work. So I picked what I thought would be good values for dfsr, but maybe it's not possible to pick such values.
A while back, someone posted a version of this code that computed the values of fdr/dfsr. I nack'd that patch because I thought the algorithm was too convoluted, but perhaps what we really need is a combination of sorts. The code should read the value of DFSR from the register, and then calculate an appropriate FDR to go with it.
--
Timur Tabi
Linux kernel developer at Freescale
next prev parent reply other threads:[~2009-09-10 13:07 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-09 9:19 [U-Boot] fsl_i2c: increase I2C timeout values and make them configurable Joakim Tjernlund
2009-09-09 14:24 ` Timur Tabi
2009-09-09 14:33 ` Joakim Tjernlund
2009-09-10 8:15 ` Joakim Tjernlund
2009-09-10 13:07 ` Timur Tabi [this message]
2009-09-10 13:20 ` Joakim Tjernlund
2009-09-10 13:29 ` Timur Tabi
2009-09-10 13:58 ` Joakim Tjernlund
2009-09-10 15:22 ` Timur Tabi
2009-09-10 15:46 ` Joakim Tjernlund
2009-09-10 15:57 ` Timur Tabi
2009-09-10 14:57 ` Joakim Tjernlund
2009-09-10 15:26 ` Timur Tabi
2009-09-10 15:53 ` Joakim Tjernlund
2009-09-10 16:13 ` Timur Tabi
2009-09-10 16:30 ` Joakim Tjernlund
2009-09-10 17:13 ` Joakim Tjernlund
2009-09-11 8:44 ` Joakim Tjernlund
[not found] ` <4AAA6ACD.9040905@free <4AAE55FA.4070702@freescale.com>
2009-09-11 15:20 ` Timur Tabi
2009-09-14 13:53 ` Detlev Zundel
2009-09-14 14:18 ` Wolfgang Grandegger
2009-09-14 14:40 ` Timur Tabi
2009-09-14 15:54 ` Joakim Tjernlund
2009-09-15 11:53 ` Wolfgang Grandegger
2009-09-15 12:24 ` Joakim Tjernlund
2009-09-15 18:53 ` Joakim Tjernlund
2009-09-14 16:01 ` Wolfgang Grandegger
2009-09-14 16:18 ` Joakim Tjernlund
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