From mboxrd@z Thu Jan 1 00:00:00 1970 From: Krzysztof Kozlowski Subject: Re: [RFC PATCH] Input: tm2-touchkey - add hardware dependency Date: Mon, 24 Apr 2017 13:56:06 +0200 Message-ID: References: <20170424094231.435f82de@endymion> <20170424114841.130cad35@endymion> <20170424133414.1395ba3d@endymion> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: Received: from mail.kernel.org ([198.145.29.136]:58294 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1169294AbdDXL4M (ORCPT ); Mon, 24 Apr 2017 07:56:12 -0400 Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 88297200D9 for ; Mon, 24 Apr 2017 11:56:10 +0000 (UTC) Received: from mail-it0-f46.google.com (mail-it0-f46.google.com [209.85.214.46]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id ECCCA200E8 for ; Mon, 24 Apr 2017 11:56:07 +0000 (UTC) Received: by mail-it0-f46.google.com with SMTP id x188so51844521itb.0 for ; Mon, 24 Apr 2017 04:56:07 -0700 (PDT) In-Reply-To: <20170424133414.1395ba3d@endymion> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Jean Delvare Cc: linux-input@vger.kernel.org, Jaechul Lee , Beomho Seo , Javier Martinez Canillas , Andi Shyti , Chanwoo Choi , Rob Herring , Dmitry Torokhov On Mon, Apr 24, 2017 at 1:34 PM, Jean Delvare wrote: > On Mon, 24 Apr 2017 11:58:09 +0200, Krzysztof Kozlowski wrote: >> On Mon, Apr 24, 2017 at 11:48 AM, Jean Delvare wrote: >> > On Mon, 24 Apr 2017 10:00:32 +0200, Krzysztof Kozlowski wrote: >> > > On Mon, Apr 24, 2017 at 9:42 AM, Jean Delvare wrote: >> > > > The tm2-touchkey driver is only useful on specific platforms. Add the >> > > > missing hardware dependency so that the driver is not proposed on >> > > > systems where the device does not exist. >> > > >> > > Although the device exists in only two upstreamed Exynos boards but >> > > there is no hardware dependency on Exynos. The hardware does not >> > > depend on Exynos. >> > >> > I understand that, and this is the reason why there was no dependency >> > expressed so far. But this is irrelevant to the problem I am trying to >> > solve, which is that people configuring a kernel for platforms where >> > this device is known to NOT exist shouldn't be bothered with a question >> > about its driver. This is what I meant with "hardware dependency" but >> > you can call it "hardware focus" or "intended hardware target" if you >> > prefer. >> >> You need a depends-like version of "imply" keyword. I think it is >> worth adding it to solve such problems and help in configuring the >> system. However I am not convinced that "depends" should be used in >> the meaning of "intended use". > > You are a bit late to the party I am afraid. COMPILE_TEST was > introduced for this very usage 4 years ago and I count 760 occurrences > of it. Not as many as I would like but I think this is going in the > right direction. That is not the purpose of COMPILE_TEST. It serves only to allow compile testing of everything, not selecting "soft dependencies". It allows you to build kernel which will not even work in certain cases. Also it does not bring any information about wanted or unwanted links - like "imply". > To be honest, I have also considered the possibility of a dedicated > keyword to express these "intended hardware target" soft dependencies. > Maybe it would make things clearer. But I never had the time to look > into it. Feel free to propose something if you are interested. Workaround might be using default = N, unless ARCH_EXYNOS. Something like: default y if ARCH_EXYNOS Best regards, Krzysztof