From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Dooks Subject: Re: [PATCH v2] i2c-s3c2410: Remove unconditional 1ms delay on each transfer Date: Mon, 5 Apr 2010 23:44:02 +0100 Message-ID: <20100405224402.GA32401@fluff.org.uk> References: <1270214109-28226-1-git-send-email-broonie@opensource.wolfsonmicro.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1270214109-28226-1-git-send-email-broonie-yzvPICuk2AATkU/dhu1WVueM+bqZidxxQQ4Iyu8u01E@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Mark Brown Cc: Ben Dooks , linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: linux-i2c@vger.kernel.org On Fri, Apr 02, 2010 at 02:15:09PM +0100, Mark Brown wrote: > The S3C I2C controller indicates completion of I2C transfers before > the bus has a stop condition on it. In order to ensure that we do not > attempt to start a new transfer before the bus is idle the driver > currently inserts a 1ms delay. This is vastly larger than is generally > required and has a visible effect on performance under load, such as > when bringing up audio CODECs or reading back status information with > non-bulk I2C reads. ok, so far no problems with this on an s3c2440. I'll add it to the next tree. -- Ben (ben-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org, http://www.fluff.org/) 'a smiley only costs 4 bytes' From mboxrd@z Thu Jan 1 00:00:00 1970 From: ben@fluff.org (Ben Dooks) Date: Mon, 5 Apr 2010 23:44:02 +0100 Subject: [PATCH v2] i2c-s3c2410: Remove unconditional 1ms delay on each transfer In-Reply-To: <1270214109-28226-1-git-send-email-broonie@opensource.wolfsonmicro.com> References: <1270214109-28226-1-git-send-email-broonie@opensource.wolfsonmicro.com> Message-ID: <20100405224402.GA32401@fluff.org.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Apr 02, 2010 at 02:15:09PM +0100, Mark Brown wrote: > The S3C I2C controller indicates completion of I2C transfers before > the bus has a stop condition on it. In order to ensure that we do not > attempt to start a new transfer before the bus is idle the driver > currently inserts a 1ms delay. This is vastly larger than is generally > required and has a visible effect on performance under load, such as > when bringing up audio CODECs or reading back status information with > non-bulk I2C reads. ok, so far no problems with this on an s3c2440. I'll add it to the next tree. -- Ben (ben at fluff.org, http://www.fluff.org/) 'a smiley only costs 4 bytes'