From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mailout1.w1.samsung.com ([210.118.77.11]:30941 "EHLO mailout1.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750991Ab3HTMlr (ORCPT ); Tue, 20 Aug 2013 08:41:47 -0400 Message-id: <52136400.7040406@samsung.com> Date: Tue, 20 Aug 2013 14:41:36 +0200 From: Andrzej Hajda MIME-version: 1.0 Subject: Re: [PATCH v2] max77693: added device tree support References: <20130819104409.GA21520@lee--X1> <1376912426-14747-1-git-send-email-a.hajda@samsung.com> <52128BAD.6020903@wwwdotorg.org> In-reply-to: <52128BAD.6020903@wwwdotorg.org> Content-type: text/plain; charset=ISO-8859-1 Content-transfer-encoding: 7bit Sender: devicetree-owner@vger.kernel.org To: Stephen Warren Cc: Lee Jones , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Rob Landley , Samuel Ortiz , Grant Likely , Sylwester Nawrocki , Jonghwa Lee , Kyungmin Park , "open list:OPEN FIRMWARE AND..." , open list List-ID: Hi, Thanks for the review. On 08/19/2013 11:18 PM, Stephen Warren wrote: > On 08/19/2013 05:40 AM, Andrzej Hajda wrote: >> max77693 mfd main device uses only wakeup field >> from max77693_platform_data. This field is mapped >> to wakeup-source common property in device tree. >> diff --git a/Documentation/devicetree/bindings/mfd/max77693.txt b/Documentation/devicetree/bindings/mfd/max77693.txt >> Optional properties: >> - regulators : The regulators of max77693 have to be instantiated under subnod >> named "regulators" using the following format. >> +- wakeup-source : Indicates if the device can wakeup the system from the sleep >> + state. > Does the property mean "can" or "should"? > > "Can" implies that the property means something about the HW. What > exactly does it mean; perhaps that some specific output pin of the chip > has been wired to an input IRQ/GPIO of the SoC or PMIC that (can) wake > up the system? If so, which pin, signal, ...? Also, doesn't this also > depend on the SoC itself supporting its input IRQ/GPIO as a wakeup > source, so isn't some co-ordination required between the SoC and chip, > such that this property doesn't mean "can wakeup the system", but simply > "a signal is routed to the SoC, so perhaps it can wakeup the system". > > "Should" implies policy, which probably shouldn't be represented in > device tree, since DT should describe the HW and not how it should be used. After short digging I have realized that "wakeup-source" property is already parsed by of_i2c_register_devices core function and it should not be parsed again by the driver itself. So I suppose the description of it can be removed from max77693 binding. Do you agree? Anyway I will prepare separate patch removing wakeup related code from probe and related field from max77693 platform_data - i2c_board_info::flag field should be used instead. > > Finally, if there was already a binding for max77693.txt, I don't think > the patch subject "added device tree support" is entirely accurate; this > change to the binding document seems to be more about adding a new > feature than adding DT support to the driver... > This patch really adds DT support to max77693 mfd driver :) The binding file which is already in kernel currently has no related code in the max77693 driver. I will add clarification in the commit message. Regards Andrzej