From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Petazzoni Subject: Re: [PATCH v2 03/10] dt-bindings: sound: Add new reset compatible for sun4i-i2s Date: Wed, 18 Jan 2017 08:20:34 +1100 Message-ID: <20170118082034.62a6be25@free-electrons.com> References: <20170117201016.A5fiHT0P@smtp2p.mail.yandex.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20170117201016.A5fiHT0P@smtp2p.mail.yandex.net> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Icenowy Zheng Cc: mark.rutland@arm.com, devicetree@vger.kernel.org, alsa-devel@alsa-project.org, wens@csie.org, linux-kernel@vger.kernel.org, mturquette@baylibre.com, tiwai@suse.com, sboyd@codeaurora.org, lgirdwood@gmail.com, robh+dt@kernel.org, perex@perex.cz, linux-sunxi@googlegroups.com, broonie@kernel.org, alexandre.belloni@free-electrons.com, maxime.ripard@free-electrons.com, =?UTF-8?B?TXlsw6huZQ==?= Josserand , linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org List-Id: devicetree@vger.kernel.org Hello, On Wed, 18 Jan 2017 01:10:00 +0800, Icenowy Zheng wrote: > > Add a new compatible for sun4i-i2s driver to handle some > > SoCs that have a reset line that must be asserted/deasserted. > > > > This new compatible, "allwinner,sun6i-a31-i2s", requires two > > properties: > > - resets: phandle to the reset line > > - reset-names: the name of the reset line ("rst"). > > Except these differences, the compatible is identical to previous one > > which will not handle a reset line. > > But I think the IP block is identical, right? > > Should a new compatible be added only for reset-line? Having a different compatible in this case allows to make some stricter error checking: the driver can make sure that if the compatible string is sun6i-a31-i2s there *IS* a reset line specified in the DT. Without a separate compatible value, such a check is not possible, and the reset line is just optional. This can lead to people being confused if they forget to specify the reset line. Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com