From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Vaussard Subject: Re: [PATCH 2/3] iio: potentiometer: mcp4531: Add device tree binding documentation Date: Tue, 21 Jun 2016 09:49:20 +0200 Message-ID: <5768F180.4080601@heig-vd.ch> References: <1466492137-32683-1-git-send-email-florian.vaussard@heig-vd.ch> <1466492137-32683-3-git-send-email-florian.vaussard@heig-vd.ch> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-iio-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Peter Rosin Cc: Florian Vaussard , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, 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 , linux-iio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: devicetree@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