From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexey Starikovskiy Subject: Re: [RFC] EC registers - Adding sysfs interface? Date: Tue, 13 Nov 2007 21:46:17 +0300 Message-ID: <4739F0F9.2030701@suse.de> References: <200711131724.31868.carlos@strangeworlds.co.uk> <4739EFB0.7080507@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from charybdis-ext.suse.de ([195.135.221.2]:56288 "EHLO emea5-mh.id5.novell.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755281AbXKMSql (ORCPT ); Tue, 13 Nov 2007 13:46:41 -0500 In-Reply-To: <4739EFB0.7080507@suse.de> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Carlos Corbacho Cc: linux-acpi@vger.kernel.org Alexey Starikovskiy wrote: > Carlos Corbacho wrote: >> Alexey, >> >> I'm considering writing a sysfs interface for the EC registers, and >> was wondering if you would be ok with such a patch (before I start >> work on it)? > What do you need that for? >> >> I'd like to expose the registers to userspace, as it is already >> possible to access the EC registers in userspace via /dev/ports (and >> quite a few of us > Well, this is not an argument. You have access to all memory through > /dev/mem, so what? >> would like to access them) - however, the problem with doing this is >> that ACPI throws quite a few warnings/ errors in dmesg whilst doing >> this; it would therefore be far preferable to expose the registers >> through sysfs, which would in turn be based on the ec_{read,write} >> calls, so we don't end up stepping on ACPI's toes. > I think it is better to do it in file system that allows seek(). So you > could do with 1 file instead of 256 of them. >> >> So, basically, I'm proposing something like: >> >> /sys/firmware/acpi/ec/ecX >> | >> |-> 0 >> |-> 1 >> |-> 2 >> |-> etc... (up to 255) >> >> Where each file returns the contents of the EC register in question >> (via ec_read()), and writing to the file calls ec_write(). > Carlos, I don't like the idea of 256 files. This will consume too many > resources and will not bring much value. > If you want to have something permanent, it should be slim and fast. How about character /dev/ec0? > If we talk about some debug/research/RE, do it as you like, but don't > ask for submission into kernel :) > Regards, > Alex. >