From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966962AbeCALEd (ORCPT ); Thu, 1 Mar 2018 06:04:33 -0500 Received: from mx2.suse.de ([195.135.220.15]:44025 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966703AbeCALEG (ORCPT ); Thu, 1 Mar 2018 06:04:06 -0500 Date: Thu, 1 Mar 2018 12:04:04 +0100 From: Jean Delvare To: Guenter Roeck Cc: Wolfram Sang , linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/2] i2c: piix4: Use usleep_range() Message-ID: <20180301120404.42f10064@endymion> In-Reply-To: <1519678013-32749-1-git-send-email-linux@roeck-us.net> References: <1519678013-32749-1-git-send-email-linux@roeck-us.net> Organization: SUSE Linux X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.31; x86_64-suse-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 26 Feb 2018 12:46:52 -0800, Guenter Roeck wrote: > The piix4 i2c driver is extremely slow. Replacing msleep() > with usleep_range() increases its speed substantially. > Use sleep ranges similar to those used in the i2c-801 driver > to keep things simple. > > Signed-off-by: Guenter Roeck > --- > v2: Changed timeout values for usleep_range() > 2000/2000 -> 2000/2100 > 500/1000 -> 250/500 > 200/500 -> 250/500 > > drivers/i2c/busses/i2c-piix4.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c > index 462948e2c535..4c1f6aaec0fc 100644 > --- a/drivers/i2c/busses/i2c-piix4.c > +++ b/drivers/i2c/busses/i2c-piix4.c > @@ -462,13 +462,13 @@ static int piix4_transaction(struct i2c_adapter *piix4_adapter) > > /* We will always wait for a fraction of a second! (See PIIX4 docs errata) */ > if (srvrworks_csb5_delay) /* Extra delay for SERVERWORKS_CSB5 */ > - msleep(2); > + usleep_range(2000, 2100); > else > - msleep(1); > + usleep_range(250, 500); > > while ((++timeout < MAX_TIMEOUT) && > ((temp = inb_p(SMBHSTSTS)) & 0x01)) > - msleep(1); > + usleep_range(250, 500); > > /* If the SMBus is still busy, we give up */ > if (timeout == MAX_TIMEOUT) { Reviewed-by: Jean Delvare -- Jean Delvare SUSE L3 Support