From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heiko Schocher Date: Thu, 03 Jul 2014 06:34:45 +0200 Subject: [U-Boot] [PATCH 1/3] i2c: tegra: use repeated start for reads In-Reply-To: <53B45156.1090202@wwwdotorg.org> References: <1403715449-2177-1-git-send-email-swarren@wwwdotorg.org> <53B45156.1090202@wwwdotorg.org> Message-ID: <53B4DD65.1050302@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hello Stephen, Am 02.07.2014 20:37, schrieb Stephen Warren: > On 06/25/2014 10:57 AM, Stephen Warren wrote: >> From: Stephen Warren >> >> I2C read transactions are typically implemented as follows: >> >> START(write) address REPEATED_START(read) data... STOP >> >> However, Tegra's I2C driver currently implements reads as follows: >> >> START(write) address STOP START(read) data... STOP >> >> This sequence confuses at least the AS3722 PMIC on the Jetson TK1 board, >> leading to corrupted read data in some cases. Fix the driver to chain >> the transactions together using repeated starts to solve this. > > Heiko, do these patches look good? Yes, they look good to me... Hmm.. as you ask, I think you want to have them in v2014.07 ? As it is a bugfix it should go into it, but as it also changes the behaviour of the driver, I am unsure if it can go in so close before the new release ... some Tested-by would be nice ... I applied them to the u-boot-i2c.git tree, and if nobody objects against them, I send tomorrow a pull request to Tom. bye, Heiko -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany