From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752278Ab1LCOqk (ORCPT ); Sat, 3 Dec 2011 09:46:40 -0500 Received: from mail-qw0-f46.google.com ([209.85.216.46]:49363 "EHLO mail-qw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751687Ab1LCOqh convert rfc822-to-8bit (ORCPT ); Sat, 3 Dec 2011 09:46:37 -0500 Subject: Re: [PATCH] w1: add fast search for single slave bus Mime-Version: 1.0 (Apple Message framework v1084) Content-Type: text/plain; charset=us-ascii From: =?iso-8859-1?Q?Jean-Fran=E7ois_Dagenais?= In-Reply-To: <1322510807-3247-1-git-send-email-h.feurstein@gmail.com> Date: Sat, 3 Dec 2011 09:46:29 -0500 Cc: Evgeniy Polyakov , linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8BIT Message-Id: <258EF057-8FF6-4432-A9E5-77F87607C45F@gmail.com> References: <1322510807-3247-1-git-send-email-h.feurstein@gmail.com> To: Hubert Feurstein X-Mailer: Apple Mail (2.1084) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2011-11-28, at 15:06, Hubert Feurstein wrote: > This enables a much more efficient way of device searching. It uses the > 1-wire read-rom operation which allows the direct reading of the slave > address. BUT this works only with exactly one slave on the bus. > > Signed-off-by: Hubert Feurstein > --- > drivers/w1/Kconfig | 8 ++++++++ > drivers/w1/w1.c | 11 +++++++++++ > 2 files changed, 19 insertions(+), 0 deletions(-) > > diff --git a/drivers/w1/Kconfig b/drivers/w1/Kconfig > index fd2c7bd..e5006bc 100644 > --- a/drivers/w1/Kconfig > +++ b/drivers/w1/Kconfig > @@ -25,6 +25,14 @@ config W1_CON > 2. Userspace commands. Includes read/write and search/alarm search commands. > 3. Replies to userspace commands. > > +config W1_FAST_SEARCH > + bool "Fast search (single slave bus only!)" > + ---help--- > + This enables a much more efficient way of device searching. It uses the > + 1-wire read-rom operation which allows the direct reading of the slave > + address. BUT this works only with exactly one slave on the bus. > + If unsure, say 'N'. > + Not needed I think, see below... > source drivers/w1/masters/Kconfig > source drivers/w1/slaves/Kconfig > > diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c > index c374978..7c648ec 100644 > --- a/drivers/w1/w1.c > +++ b/drivers/w1/w1.c > @@ -892,6 +892,17 @@ void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb > break; > } > > +#ifdef CONFIG_W1_FAST_SEARCH > + if (dev->max_slave_count == 1) { > + w1_write_8(dev, W1_READ_ROM); > + > + if (w1_read_block(dev, (u8 *)&rn, 8) == 8 && rn) > + cb(dev, rn); > + > + break; > + } > +#endif > + I would drop the CONFIG item and just add this "if" block to the search function unconditionnaly. Unless I am missing something, it wouldn't hurt multi-slave setups... > /* Start the search */ > w1_write_8(dev, search_type); > for (i = 0; i < 64; ++i) { > -- > 1.7.4.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/