From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Dooks Subject: Re: [PATCH] i2c-s3c2410: Decrease delay after end of transaction Date: Tue, 20 Apr 2010 12:13:14 +0100 Message-ID: <20100420111314.GD2234@trinity.fluff.org> References: <1271760799-30913-1-git-send-email-yauhen.kharuzhy@promwad.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1271760799-30913-1-git-send-email-yauhen.kharuzhy@promwad.com> Sender: linux-samsung-soc-owner@vger.kernel.org To: Yauhen Kharuzhy Cc: Ben Dooks , Jean Delvare , linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org List-Id: linux-i2c@vger.kernel.org On Tue, Apr 20, 2010 at 01:53:19PM +0300, Yauhen Kharuzhy wrote: > msleep(1) which has been used for delay after issuing a STOP condition > to bus cause very big delay (min 1/HZ s). This is makes bulk register > update in I2C devices (for instance video camera) very slowly. > > Seems that this delay can be safely decreased to few tens of > microseconds. Mark Brown has already submitted a similar patch that uses the bus busy bit. will be in the i2c-next tree soon. > Signed-off-by: Yauhen Kharuzhy > --- > drivers/i2c/busses/i2c-s3c2410.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c > index d27072b..de20a4e 100644 > --- a/drivers/i2c/busses/i2c-s3c2410.c > +++ b/drivers/i2c/busses/i2c-s3c2410.c > @@ -521,7 +521,7 @@ static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c, > > /* ensure the stop has been through the bus */ > > - msleep(1); > + udelay(50); > > out: > return ret; > -- > 1.6.6.1 > -- -- Ben Q: What's a light-year? A: One-third less calories than a regular year.