From: ludovic.desroches@atmel.com (ludovic.desroches) Date: Mon, 27 Aug 2012 15:27:48 +0200 Subject: [PATCH v11 4/4] G45 TWI: remove open drain setting for twi function gpios In-Reply-To: References: <6acdbd0f06cb9902efc510346564e10b07fa0b91.1345618760.git.n.voss@weinmann.de> <503B4AE6.4090107@atmel.com> Message-ID: <503B75D4.2030803@atmel.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Le 08/27/2012 03:22 PM, Voss, Nikolaus a ?crit : > Hi Ludovic, > > ludovic.desroches wrote on Monday, August 27, 2012 12:25 PM: >> Le 11/08/2011 12:11 PM, Nikolaus Voss a ?crit : >>> The G45 datasheets explicitly states that setting the open drain property >>> on peripheral function gpios is not allowed. (How about other A91 chips?) >> >> Did you remove open drain because you had some issues or because you >> had seen it into datasheet? >> >> I tried with and without open drain. The behavior was the same. Looking >> to the G45 datasheet, I didn't see that the open drain property is not >> allowed on peripheral function gpios: >> >> 'The Multi Drive can be selected whether the I/O line >> is controlled by the PIO controller or assigned to a peripheral function.' >> >> The datasheet should have been updated or there is another place where >> it is mentioned that open drain property is not allowed in this case. > > well, it didn't work on my G45. I found the following note in the > TWI chapter 31.6.1 of the G45 datasheet: > "The user must not program TWD and TWCK as open-drain. > It is already done by the hardware." Ok so it seems there is a contradiction. I'll try to inquire about this point. Regards Ludovic > > After removing the open-drain setting, it worked. > > Regards, > Nikolaus > > > >