Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934043AbdGTGbW (ORCPT ); Thu, 20 Jul 2017 02:31:22 -0400 Received: from mail-it0-f65.google.com ([209.85.214.65]:33708 "EHLO mail-it0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933005AbdGTGbU (ORCPT ); Thu, 20 Jul 2017 02:31:20 -0400 MIME-Version: 1.0 In-Reply-To: <20170718091906.trvcaacdfrizjfks@dell> References: <20170712101309.6045-1-enric.balletbo@collabora.com> <20170712101309.6045-2-enric.balletbo@collabora.com> <20170718091906.trvcaacdfrizjfks@dell> From: Enric Balletbo Serra Date: Thu, 20 Jul 2017 08:31:18 +0200 Message-ID: Subject: Re: [PATCH v3 1/4] mfd: cros_ec: Get rid of cros_ec_check_features from cros_ec_dev. To: Lee Jones Cc: Gwendal Grignou , Enric Balletbo i Serra , Jonathan Cameron , Benson Leung , Javier Martinez Canillas , Guenter Roeck , Linux Kernel , linux-iio@vger.kernel.org, rtc-linux@googlegroups.com Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id v6K6VZCP028792 Content-Length: 2352 Lines: 60 Lee, 2017-07-18 11:19 GMT+02:00 Lee Jones : > On Mon, 17 Jul 2017, Enric Balletbo Serra wrote: > >> Hi Gwendal, >> >> 2017-07-13 22:33 GMT+02:00 Gwendal Grignou : >> > On Wed, Jul 12, 2017 at 3:13 AM, Enric Balletbo i Serra >> > wrote: >> >> The cros_ec_dev driver should be used only to expose the Chrome OS Embedded >> >> Controller to user-space and should not be used to add MFD devices by >> >> calling mfd_add_devices. This patch moves this logic to the MFD cros_ec >> >> driver and removes the MFD bits from the character device driver. Also >> >> makes independent the IIO driver from the character device as also has no >> >> sense. >> > >> > cros_ec_dev serves another purpose: it allows to represent an EC that >> > does not have a cros_ec structure. It happens when there are several >> > EC in a chromebook, and one EC is connected through another EC. >> > One example is Samus (Pixel 2): where we have: >> > >> > (main SOC, Application Processor) AP --> (main Embedded Controller) EC >> > ---> (Power Delivery [PD}) EC >> > >> > We access to the PD EC via pass-through commands through the main EC. >> > Each EC has a cros_ec_dev structure, but only the main EC as a >> > cros_ec_device structure (I will forever regret the structure names). >> > >> > Now form the AP point of view, both ECs use the same protocol. That >> > why the sensors and other devcies that are registered by looking at >> > the feature fields are registered with cros_ec_dev as their parent. >> > Other devices that are registered from the device tree, predating the >> > feature field support, are registered with cros_ec_device as their >> > parent. >> > >> >> Interesting I didn't know that. So are you saying that this patch will >> break support for devices like Pixel 2? I tested the patches on >> various devices but not on Pixel 2 so could be. > > Does this affect the rest of the series? > Yes, because this patch moves cros_ec_check_features from char dev driver... > Or should I review/apply as usual? > Please, hold on while I figure out what's exactly the problem with Samus. Sorry for the noise. Cheers, Enric > -- > Lee Jones > Linaro STMicroelectronics Landing Team Lead > Linaro.org │ Open source software for ARM SoCs > Follow Linaro: Facebook | Twitter | Blog