From: Moiz Sonasath <m-sonasath@ti.com>
Date: Wed, 17 Feb 2010 00:57:21 +0000 (-0600)
Subject: mfd: Disable TWL4030/5030 I2C1/I2C4 internal pull-ups
X-Git-Tag: v2.6.34-rc1~9^2~20
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a29aaf55cd6faa75e35abfe00bd3ffc537490485;p=pandora-kernel.git

mfd: Disable TWL4030/5030 I2C1/I2C4 internal pull-ups

This patch disables TWL4030/5030 I2C1 adn I2C4(SR) internal pull-up, to
use only the external HW resistor >=470 Ohm for the assured
functionality in HS mode.

While testing the I2C in High Speed mode, it was discovered that
without a proper pull-up resistor, there is data corruption during
multi-byte transfer. RTC(time_set) test case was used for testing.

From the analysis done, it was concluded that ideally we need a
pull-up of 1.6k Ohm(recomended) or atleast 470 Ohm or greater for
assured performance in HS mode.

Signed-off-by: Moiz Sonasath <m-sonasath@ti.com>
Signed-off-by: Allen Pais <allen.pais@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
---

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