Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752861AbcLLNID (ORCPT ); Mon, 12 Dec 2016 08:08:03 -0500 Received: from us01smtprelay-2.synopsys.com ([198.182.60.111]:47253 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750712AbcLLNIA (ORCPT ); Mon, 12 Dec 2016 08:08:00 -0500 Subject: Re: [PATCH v5 1/2] Add OV5647 device tree documentation To: Sakari Ailus , Ramiro Oliveira References: <20161212114900.GS16630@valkosipuli.retiisi.org.uk> <0f72309f-ec5e-4252-f6d7-7a7f7a9dc4c5@synopsys.com> <20161212121947.GU16630@valkosipuli.retiisi.org.uk> CC: , , , , , , , , , , , , , , , , , , , From: Ramiro Oliveira Message-ID: Date: Mon, 12 Dec 2016 13:07:53 +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: <20161212121947.GU16630@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: 4243 Lines: 115 Hi Sakari On 12/12/2016 12:19 PM, Sakari Ailus wrote: > 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? > The reset line is hardwired to a GPIO controller that when powered-on removes the sensor from reset. However I have no control over the GPIO controller. >> >> 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 >