Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757813AbaKTSQ0 (ORCPT ); Thu, 20 Nov 2014 13:16:26 -0500 Received: from mail-qc0-f177.google.com ([209.85.216.177]:48880 "EHLO mail-qc0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757419AbaKTSQZ (ORCPT ); Thu, 20 Nov 2014 13:16:25 -0500 MIME-Version: 1.0 In-Reply-To: <546DD783.2030902@collabora.co.uk> References: <1416238213-15263-1-git-send-email-javier.martinez@collabora.co.uk> <1416238213-15263-3-git-send-email-javier.martinez@collabora.co.uk> <20141118142645.GD24004@x1> <546DD783.2030902@collabora.co.uk> From: Bill Richardson Date: Thu, 20 Nov 2014 10:16:03 -0800 X-Google-Sender-Auth: uB1vrhszeBXEWPrjE_gV6Q9czq4 Message-ID: Subject: Re: [PATCH 2/3] mfd: cros_ec: Create sysfs attributes for the ChromeOS EC. To: Javier Martinez Canillas Cc: Lee Jones , Doug Anderson , Olof Johansson , Simon Glass , Gwendal Grignou , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 20, 2014 at 3:58 AM, Javier Martinez Canillas wrote: > > I don't really know why there are two interfaces for this but I guess > that different user-space utilities use one or another. Maybe the > ChromiumOS folks can comment on this. The /dev/cros_ec interface responds to ioctls and is the primary means by which userspace applications talk to the EC (replacing three really awkward bus-specific libraries). It emits a simplified version string when read so that humans can tell if the EC is alive and speaking the same protocol that the userspace app expects. The /sys/class/chromeos/cros_ec/* tree was originally envisioned as a way to provide additional human-readable interfaces to a subset of the EC commands, but except for the lightbar it's not often used. The version component here shows all the version-related info that the EC can provide. I apologize for the poor kernel conventions used here. In my ignorance, I apparently chose the worst code possible to use as a template, and then invented some new stupidness of my own. Bill -- Art for Art's Sake Engineering for Money -- 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/