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From: Richard Retanubun <RichardRetanubun@RuggedCom.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH] Coldfire: I2C: Update I2CFDR frequency divider 0x0E value from 192 to 204
Date: Wed, 18 Mar 2009 13:07:27 -0400	[thread overview]
Message-ID: <49C12A4F.5090607@RuggedCom.com> (raw)

 From 9a7a9dfb1ed367b275bc19f7c40c98b63de75fb2 Mon Sep 17 00:00:00 2001
From: Richard Retanubun <RichardRetanubun@RuggedCom.com>
Date: Wed, 18 Mar 2009 12:52:35 -0400
Subject: [PATCH] Update I2CFDR frequency divider 0x0E value from 192 to 204.

This patch changes the divider factor of 14 for I2CFDR.
Through empirical experiments on a M5271EVB with a 25MHz osc,
multiplied to 75MHz system frequency, the divider 0x0E that is
supposed to be div-by-192, results in i2c clock of ~376 KHz
(which is ~div-by-204). Using the alternate divider for div-by-192
(49) results in an i2c clock of ~390 KHz, a better clock approximation.

Signed-off-by: Richard Retanubun <RichardRetanubun@RuggedCom.com>
---
  drivers/i2c/fsl_i2c.c |    4 ++--
  1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/fsl_i2c.c b/drivers/i2c/fsl_i2c.c
index ce646fd..c61bf84 100644
--- a/drivers/i2c/fsl_i2c.c
+++ b/drivers/i2c/fsl_i2c.c
@@ -113,8 +113,8 @@ static const struct {
  	{56, 41}, {64, 42}, {68, 7}, {72, 43},
  	{80, 8}, {80, 44}, {88, 9}, {96, 41},
  	{104, 10}, {112, 42}, {128, 11}, {128, 43},
-	{144, 12}, {160, 13}, {160, 48}, {192, 14},
-	{192, 49}, {224, 50}, {240, 15}, {256, 51},
+	{144, 12}, {160, 13}, {160, 48}, {192, 49},
+	{204, 14}, {224, 50}, {240, 15}, {256, 51},
  	{288, 16}, {320, 17}, {320, 52}, {384, 18},
  	{384, 53}, {448, 54}, {480, 19}, {512, 55},
  	{576, 20}, {640, 21}, {640, 56}, {768, 22},
-- 
1.5.6.5

             reply	other threads:[~2009-03-18 17:07 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-03-18 17:07 Richard Retanubun [this message]
2009-03-18 17:22 ` [U-Boot] [PATCH] Coldfire: I2C: Update I2CFDR frequency divider 0x0E value from 192 to 204 Kumar Gala
2009-03-18 18:04   ` Richard Retanubun
2009-03-18 19:01     ` Kumar Gala
2009-03-19  7:47 ` Heiko Schocher
2009-03-25  2:20   ` TC Liew
2009-03-25 12:50     ` Richard Retanubun

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