From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933025AbcFUILn (ORCPT ); Tue, 21 Jun 2016 04:11:43 -0400 Received: from mailcl2.heig-vd.ch ([193.134.216.183]:38187 "EHLO heig-vd.ch" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753576AbcFUILM (ORCPT ); Tue, 21 Jun 2016 04:11:12 -0400 X-Greylist: delayed 1292 seconds by postgrey-1.27 at vger.kernel.org; Tue, 21 Jun 2016 04:11:10 EDT Subject: Re: [PATCH 2/3] iio: potentiometer: mcp4531: Add device tree binding documentation To: Peter Rosin References: <1466492137-32683-1-git-send-email-florian.vaussard@heig-vd.ch> <1466492137-32683-3-git-send-email-florian.vaussard@heig-vd.ch> CC: Florian Vaussard , , Jonathan Cameron , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Slawomir Stepien , Joachim Eastwood , Matt Ranostay , Cristina Moraru , , From: Florian Vaussard Message-ID: <5768F180.4080601@heig-vd.ch> Date: Tue, 21 Jun 2016 09:49:20 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.192.127.110] X-ClientProxiedBy: EINTFEA.einet.ad.eivd.ch (10.192.41.59) To EINTMBXC.einet.ad.eivd.ch (10.192.41.65) X-MailCleaner-RDNS: invalid reverse DNS for 10.192.41.59 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On 06/21/2016 09:38 AM, Peter Rosin wrote: > On 2016-06-21 08:55, Florian Vaussard wrote: >> Add the device tree documentation for all the supported parts. Apart the >> compatible string and standard I2C binding, no other binding is currently >> needed. >> >> Signed-off-by: Florian Vaussard >> --- >> .../bindings/iio/potentiometer/mcp4531.txt | 84 ++++++++++++++++++++++ >> 1 file changed, 84 insertions(+) >> create mode 100644 Documentation/devicetree/bindings/iio/potentiometer/mcp4531.txt >> >> diff --git a/Documentation/devicetree/bindings/iio/potentiometer/mcp4531.txt b/Documentation/devicetree/bindings/iio/potentiometer/mcp4531.txt >> new file mode 100644 >> index 0000000..b052299 >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/iio/potentiometer/mcp4531.txt >> @@ -0,0 +1,84 @@ >> +* Microchip MCP453X/454X/455X/456X/463X/464X/465X/466X Digital Potentiometer >> + driver >> + >> +The node for this driver must be a child node of a I2C controller, hence >> +all mandatory properties for your controller must be specified. See directory: >> + >> + Documentation/devicetree/bindings/i2c >> + >> +for more details. >> + >> +Required properties: >> + - compatible: Must be one of the following, depending on the >> + model: >> + "microchip,mcp4531-502" >> + "microchip,mcp4531-103" >> + "microchip,mcp4531-503" > > *snip* > > I'm not directly opposed, but I have used the following and DT booting > works like a charm here. > > mcp4651-104@28 { > compatible = "mcp4651-104"; > reg = <0x28>; > }; > I was not aware that the i2c subsystem had a facility to match the compatible string against i2c_device_id. Good to know. > But, I suppose some DT documentation is not bad, and my understanding of > the device instantiation process and the i2c/dt interactions are not > complete, so my DT snippet might be an abomination? I'll leave the > decision if this is needed to someone with more experience on how other > drivers handle this. > Your compatible string is missing the vendor ID (microchip). This is the only objection that I can see to your proposition. Let's wait to hear from a DT maintainer. Thanks, Florian