From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755295AbbATQw2 (ORCPT ); Tue, 20 Jan 2015 11:52:28 -0500 Received: from bhuna.collabora.co.uk ([93.93.135.160]:60988 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751453AbbATQwZ (ORCPT ); Tue, 20 Jan 2015 11:52:25 -0500 Message-ID: <54BE87C4.4040108@collabora.co.uk> Date: Tue, 20 Jan 2015 17:52:20 +0100 From: Javier Martinez Canillas User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.2.0 MIME-Version: 1.0 To: Lee Jones CC: Olof Johansson , Doug Anderson , Bill Richardson , Simon Glass , Gwendal Grignou , Jonathan Corbet , linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH RESEND v2 3/7] mfd: cros_ec: Add cros_ec_lpc driver for x86 devices References: <1420205572-2640-1-git-send-email-javier.martinez@collabora.co.uk> <1420205572-2640-4-git-send-email-javier.martinez@collabora.co.uk> <20150120081104.GT21886@x1> <54BE7B08.1010900@collabora.co.uk> <20150120163410.GC30656@x1> In-Reply-To: <20150120163410.GC30656@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 01/20/2015 05:34 PM, Lee Jones wrote: >> >> So, the Embedded Controller driver (drivers/mfd/cros_ec.c) falls into that >> category and in fact has been in the mfd driver for a long time. Now, if >> an mfd device support different type of buses (e.g: i2c, spi, etc) I see >> that both the core driver and the driver for the transport method are >> in the drivers/mfd directory. As an example: >> >> drivers/mfd/arizona-{core,i2c,spi}.c >> drivers/mfd/da9052-{core,i2c,spi}.c >> drivers/mfd/mc13xxx-{core,i2c,spi}.c >> drivers/mfd/tps65912-{core,i2c,spi}.c >> drivers/mfd/wm831x-{core,i2c,spi,otp}.c >> >> In the cros_ec case, we already have drivers/mfd/cros_ec_{i2c,spi}.c so >> since the Low Pin Count is another transport method I thought that this >> driver belonged to the drivers/mfd directory. >> >> Now, all those drivers may be wrong and the buses don't belong to the mfd >> subsystem but then I think we need to document that since it seems that is >> the correct way to do it just by looking at the other drivers. > > I don't think the drivers you mentioned above do anything practical. > For instance, they are not SPI/IC2/etc drivers. They should only > offer some abstraction layers which are used to communicate with the > device. The driver you are submitting looks a lot more like a device > driver, which should live somewhere else. Don't ask me where though, > I'm not even sure what a Low Pin Controller does. > The driver added by $subject doesn't really do anything practical either. LPC [0] is just another transport method like i2c or spi that is used on x86 Chromebooks to access the Embedded Controller. So the driver is really not that different than the cros_ec_{i2c,spi}.c drivers. Best regards, Javier [0]: http://en.wikipedia.org/wiki/Low_Pin_Count