From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752305AbcLLMT4 (ORCPT ); Mon, 12 Dec 2016 07:19:56 -0500 Received: from nblzone-211-213.nblnetworks.fi ([83.145.211.213]:41912 "EHLO hillosipuli.retiisi.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751615AbcLLMTz (ORCPT ); Mon, 12 Dec 2016 07:19:55 -0500 Date: Mon, 12 Dec 2016 14:19:47 +0200 From: Sakari Ailus To: Ramiro Oliveira Cc: mchehab@kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, robh+dt@kernel.org, devicetree@vger.kernel.org, davem@davemloft.net, gregkh@linuxfoundation.org, geert+renesas@glider.be, akpm@linux-foundation.org, linux@roeck-us.net, hverkuil@xs4all.nl, dheitmueller@kernellabs.com, slongerbeam@gmail.com, lars@metafoo.de, robert.jarzmik@free.fr, pavel@ucw.cz, pali.rohar@gmail.com, sakari.ailus@linux.intel.com, mark.rutland@arm.com, CARLOS.PALMINHA@synopsys.com Subject: Re: [PATCH v5 1/2] Add OV5647 device tree documentation Message-ID: <20161212121947.GU16630@valkosipuli.retiisi.org.uk> References: <20161212114900.GS16630@valkosipuli.retiisi.org.uk> <0f72309f-ec5e-4252-f6d7-7a7f7a9dc4c5@synopsys.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0f72309f-ec5e-4252-f6d7-7a7f7a9dc4c5@synopsys.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Ramiro, On Mon, Dec 12, 2016 at 12:15:04PM +0000, Ramiro Oliveira wrote: > Hi Sakari > > On 12/12/2016 11:49 AM, Sakari Ailus wrote: > > Hi Ramiro, > > > > On Mon, Dec 12, 2016 at 11:39:31AM +0000, Ramiro Oliveira wrote: > >> Hi Sakari, > >> > >> Thank you for the feedback. > >> > >> On 12/7/2016 10:33 PM, Sakari Ailus wrote: > >>> Hi Ramiro, > >>> > >>> Thank you for the patch. > >>> > >>> On Mon, Dec 05, 2016 at 05:36:33PM +0000, Ramiro Oliveira wrote: > >>>> Add device tree documentation. > >>>> > >>>> Signed-off-by: Ramiro Oliveira > >>>> --- > >>>> .../devicetree/bindings/media/i2c/ov5647.txt | 19 +++++++++++++++++++ > >>>> 1 file changed, 19 insertions(+) > >>>> create mode 100644 Documentation/devicetree/bindings/media/i2c/ov5647.txt > >>>> > >>>> diff --git a/Documentation/devicetree/bindings/media/i2c/ov5647.txt b/Documentation/devicetree/bindings/media/i2c/ov5647.txt > >>>> new file mode 100644 > >>>> index 0000000..4c91b3b > >>>> --- /dev/null > >>>> +++ b/Documentation/devicetree/bindings/media/i2c/ov5647.txt > >>>> @@ -0,0 +1,19 @@ > >>>> +Omnivision OV5647 raw image sensor > >>>> +--------------------------------- > >>>> + > >>>> +OV5647 is a raw image sensor with MIPI CSI-2 and CCP2 image data interfaces > >>>> +and CCI (I2C compatible) control bus. > >>>> + > >>>> +Required properties: > >>>> + > >>>> +- compatible : "ovti,ov5647"; > >>>> +- reg : I2C slave address of the sensor; > >>>> + > >>>> +The common video interfaces bindings (see video-interfaces.txt) should be > >>>> +used to specify link to the image data receiver. The OV5647 device > >>>> +node should contain one 'port' child node with an 'endpoint' subnode. > >>>> + > >>>> +Following properties are valid for the endpoint node: > >>>> + > >>>> +- data-lanes : (optional) specifies MIPI CSI-2 data lanes as covered in > >>>> + video-interfaces.txt. The sensor supports only two data lanes. > >>> > >>> Doesn't this sensor require a external clock, a reset GPIO and / or a > >>> regulator or a few? Do you need data-lanes, unless you can change the order > >>> or the number? > >> > >> In the setup I'm using, I'm not aware of any reset GPIO or regulator. I do use a > >> external clock but it's fixed and not controlled by SW. Should I add a property > >> for this? > > > > The sensor datasheet defines a power-up and power-down sequence for the > > device. If you don't implement these sequences in the driver on a DT based > > system, nothing suggests that they're implemented correctly. Could it be > > that the boot loader simply enables the regulators or another device > > requires them to be enabled? > > > > I presume at least the reset GPIO should be controlled explicitly in order > > to ensure correct function. Although hardware can be surprising: I have one > > production system that has no reset GPIO for the sensor albeit the sensor > > datasheet says that's part of the power up sequence. > > > > Sorry for the misunderstanding. I wanted to say that, there is no SW controlled > reset. In the board we're using to connect the sensor to our D-PHY we have a > GPIO controller that when it receives power, it removes the sensor from reset, > so I have no control over that. Do you mean to say that there's a GPIO controller but there's not (yet?) a driver for that or that the reset line is actually hard-wired to something else? > > Regarding the clock, should I create a new property? Yes. The sensor does require a clock. > > And also, regarding the data-lanes, AFAIK it isn't possible to change the order > of the data and clock lanes so should I remove that property? Sounds good to me. > > >> > >>> > >>> An example DT snippet wouldn't hurt. > >> > >> Sure, I can add a example snippet. > >> > >>> > >> > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-media" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Sakari Ailus e-mail: sakari.ailus@iki.fi XMPP: sailus@retiisi.org.uk