From mboxrd@z Thu Jan 1 00:00:00 1970 From: Krzysztof Kozlowski Subject: Re: [PATCH] spi: s3c64xx: Get fifosize via device tree Date: Sun, 14 Feb 2016 17:31:52 +0900 Message-ID: <56C03B78.1040100@samsung.com> References: <1455031585-11113-1-git-send-email-ym0914@gmail.com> <56C02634.8020204@samsung.com> <56C03731.5040107@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pa0-f50.google.com ([209.85.220.50]:33886 "EHLO mail-pa0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751468AbcBNIcD (ORCPT ); Sun, 14 Feb 2016 03:32:03 -0500 In-Reply-To: <56C03731.5040107@gmail.com> Sender: linux-samsung-soc-owner@vger.kernel.org List-Id: linux-samsung-soc@vger.kernel.org To: Youngmin Nam , kgene@kernel.org, broonie@kernel.org Cc: k.kozlowski.k@gmail.com, linux-samsung-soc@vger.kernel.org, linux-spi@vger.kernel.org W dniu 14.02.2016 o 17:13, Youngmin Nam pisze: > Hello Krzysztof, > > As you mentioned, spi fifosize is not configurable in the given SoC. > The point is we can set fifosize without changing driver code. > For example, if some SoC in exynos7 series has different spi fifosize of on each channel with current > our compatible, we can't cover this situation without adding new compatible into spi driver code. Yes, because new SoC is not compatible with old ones... so a new compatible is required! > Whenever new SoC kind of exynos7 come out, we should add new compatible into driver code only for fifosize change. > I think this is not efficient. I think we can reduces this works through DT handling. I agree that this is not the most efficient possible way of setting some specific properties of devices but this is the way how DT works. What if the property is not present on board with Exynos7? What value should be used? You did not want to add a new compatible but you are adding a compatible-like property which apparently is required for some devices. That looks bad. It's easy to make a mistake, messes with compatibles. Best regards, Krzysztof