Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756607AbaKTL7J (ORCPT ); Thu, 20 Nov 2014 06:59:09 -0500 Received: from bhuna.collabora.co.uk ([93.93.135.160]:32887 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751680AbaKTL7G (ORCPT ); Thu, 20 Nov 2014 06:59:06 -0500 Message-ID: <546DD783.2030902@collabora.co.uk> Date: Thu, 20 Nov 2014 12:58:59 +0100 From: Javier Martinez Canillas User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.0 MIME-Version: 1.0 To: Lee Jones CC: Doug Anderson , Bill Richardson , Olof Johansson , Simon Glass , Gwendal Grignou , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/3] mfd: cros_ec: Create sysfs attributes for the ChromeOS EC. 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> In-Reply-To: <20141118142645.GD24004@x1> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Lee, On 11/18/2014 03:26 PM, Lee Jones wrote: > On Mon, 17 Nov 2014, Javier Martinez Canillas wrote: > >> From: Bill Richardson >> >> This adds the first few sysfs attributes for the Chrome OS EC. These >> controls are made available under /sys/devices/virtual/chromeos/cros_ec >> >> flashinfo - display current flash info > > drivers/mtd? > >> reboot - tell the EC to reboot in various ways > > drivers/power? > Well this driver is special in the sense that there is a Cortex-M Embedded Controller that has different peripherals (flash, keyboard, charger, etc). The kernel communicates with these peripherals by using a tunnel through the protocol used to communicate with the Embedded Controller (SPI/I2C/LPC). But you are right that this is not suitable for drivers/mfd, I just added there because that is the location in the downstream ChromeOS kernel but like you said, the MFD subsystem should not be a dumping ground for devices that is not clear where should live. On v2 I'll add this sysfs interface and the dev to drivers/platform/chrome/ since I think is a better place for the cros_ec dev driver. It will still be spawns from the cros_ec MFD driver though but that is OK for you AFAIU. >> version - information about the EC software and hardware > > What's the difference between this version and the version you can > read in the new _dev driver? > The version information read from the cros_ec dev interface is a subset of the information read from the version sysfs, e.g: $ cat /dev/cros_ec 1.0.0 pit_v1.1.1198-1cd618e pit_v1.1.1198-1cd618e read-only $ cat /sys/class/chromeos/cros_ec/version RO version: pit_v1.1.1198-1cd618e RW version: pit_v1.1.1198-1cd618e Firmware copy: RO Build info: pit_v1.1.1198-1cd618e 2014-04-30 16:29:52 @build122-m2 Chip vendor: stm Chip name: stm32l15x Chip revision: Board version: 0 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. Best regards, Javier -- 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/