Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754039AbcL3NGB (ORCPT ); Fri, 30 Dec 2016 08:06:01 -0500 Received: from mail-qk0-f181.google.com ([209.85.220.181]:35745 "EHLO mail-qk0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753973AbcL3NFt (ORCPT ); Fri, 30 Dec 2016 08:05:49 -0500 MIME-Version: 1.0 In-Reply-To: <20161229162919.j2ej2cyeuoqnxykf@earth> References: <1481494905-18037-1-git-send-email-bgolaszewski@baylibre.com> <1481494905-18037-3-git-send-email-bgolaszewski@baylibre.com> <20161229162919.j2ej2cyeuoqnxykf@earth> From: Linus Walleij Date: Fri, 30 Dec 2016 14:05:48 +0100 Message-ID: Subject: Re: [PATCH 2/2] iio: misc: add support for GPIO power switches To: Sebastian Reichel Cc: Bartosz Golaszewski , Jonathan Cameron , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , Rob Herring , Mark Rutland , "linux-iio@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Kevin Hilman , Patrick Titiano , Neil Armstrong , Alexandre Courbot , "linux-gpio@vger.kernel.org" , "linux-pm@vger.kernel.org" , Mark Brown , Liam Girdwood 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-Length: 1656 Lines: 41 n Thu, Dec 29, 2016 at 5:29 PM, Sebastian Reichel wrote: > On Wed, Dec 28, 2016 at 01:50:17PM +0100, Linus Walleij wrote: >> On Sun, Dec 11, 2016 at 11:21 PM, Bartosz Golaszewski >> wrote: >> >> > Some power-measuring ADCs work together with power load switches which >> > allow to power-cycle measured devices. >> > >> > An example use case would be measuring the power consumption of a >> > development board during boot using a power monitor such as TI INA226 >> > and power-cycling the board remotely using a TPS229* power switch. >> > >> > Add an iio driver for simple GPIO power switches and expose a sysfs >> > attribute allowing to toggle their state. >> > >> > Signed-off-by: Bartosz Golaszewski >> >> I don't get this, isn't this doing the same as >> drivers/power/reset/gpio-poweroff.c >> ? >> >> With the only difference that the latter uses the standard syscall >> from pm_power_off to reboot the system instead of some random >> sysfs file. > > As far as I understand it, the TPS229 is used by Barzosz to poweroff > a remote system. The gpio-poweroff driver is used to poweroff the > local system. Thanks yeah I understood this from the context of later patches. Well if such a property is used it should be the property of the remote system per se, and the remote system should then also be desribed in DT, not half-described by dangling references at random nodes. So this needs to be re-architected to either describe the remote system in DT and handle it in the kernel, or handle it all from userspace if it is a one-off non-product thing. Yours, Linus Walleij