Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752384AbcLLMPR (ORCPT ); Mon, 12 Dec 2016 07:15:17 -0500 Received: from us01smtprelay-2.synopsys.com ([198.182.60.111]:46565 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750933AbcLLMPP (ORCPT ); Mon, 12 Dec 2016 07:15:15 -0500 Subject: Re: [PATCH v5 1/2] Add OV5647 device tree documentation To: Sakari Ailus , Ramiro Oliveira References: <20161212114900.GS16630@valkosipuli.retiisi.org.uk> CC: , , , , , , , , , , , , , , , , , , , From: Ramiro Oliveira Message-ID: <0f72309f-ec5e-4252-f6d7-7a7f7a9dc4c5@synopsys.com> Date: Mon, 12 Dec 2016 12:15:04 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <20161212114900.GS16630@valkosipuli.retiisi.org.uk> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.107.25.125] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3317 Lines: 89 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. Regarding the clock, should I create a new property? 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? >> >>> >>> An example DT snippet wouldn't hurt. >> >> Sure, I can add a example snippet. >> >>> >> >