Re: [PATCH v6 1/2] media: i2c/ov5645: add the device tree binding document

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Todor,

On Wednesday 19 Oct 2016 12:14:55 Todor Tomov wrote:
> On 10/19/2016 11:49 AM, Laurent Pinchart wrote:
> > On Friday 14 Oct 2016 15:01:08 Todor Tomov wrote:
> >> On 09/08/2016 03:22 PM, Laurent Pinchart wrote:
> >>> On Thursday 08 Sep 2016 12:13:54 Todor Tomov wrote:
> >>>> Add the document for ov5645 device tree binding.
> >>>> 
> >>>> Signed-off-by: Todor Tomov <todor.tomov@linaro.org>
> >>>> ---
> >>>> 
> >>>>  .../devicetree/bindings/media/i2c/ov5645.txt       | 52 ++++++++++++++
> >>>>  1 file changed, 52 insertions(+)
> >>>>  create mode 100644
> >>>>  Documentation/devicetree/bindings/media/i2c/ov5645.txt
> >>>> 
> >>>> diff --git a/Documentation/devicetree/bindings/media/i2c/ov5645.txt
> >>>> b/Documentation/devicetree/bindings/media/i2c/ov5645.txt new file mode
> >>>> 100644
> >>>> index 0000000..bcf6dba
> >>>> --- /dev/null
> >>>> +++ b/Documentation/devicetree/bindings/media/i2c/ov5645.txt
> >>>> @@ -0,0 +1,52 @@
> >>>> +* Omnivision 1/4-Inch 5Mp CMOS Digital Image Sensor
> >>>> +
> >>>> +The Omnivision OV5645 is a 1/4-Inch CMOS active pixel digital image
> >>>> sensor with
> >>>> +an active array size of 2592H x 1944V. It is programmable through a
> >>>> serial I2C
> >>>> +interface.
> >>>> +
> >>>> +Required Properties:
> >>>> +- compatible: Value should be "ovti,ov5645".
> >>>> +- clocks: Reference to the xclk clock.
> >>>> +- clock-names: Should be "xclk".
> >>>> +- clock-frequency: Frequency of the xclk clock.
> >>>> +- enable-gpios: Chip enable GPIO. Polarity is GPIO_ACTIVE_HIGH.
> > 
> > By the way, isn't the pin called pwdnb and isn't it active low ?
> 
> Yes, the pin is called "pwdnb" and is active low (must be up for power to be
> up). I have changed the name to "enable" as it is more generally used -
> this change was suggested by Rob Herring. As the logic switches with this
> change of the name I have stated it is active high which ends up in the
> same condition (enable must be up for the power to be up). I think this is
> correct, isn't it?

I thought that the rule was to name the GPIO properties based on the name of 
the pin. I could be wrong though. Rob, what's your opinion ?

> >>>> +- reset-gpios: Chip reset GPIO. Polarity is GPIO_ACTIVE_LOW.
> >>> 
> >>> Shouldn't the enable and reset GPIOs be optional ?
> >> 
> >> I don't think so. The operations on the GPIOs are part of the power up
> >> sequence of the sensor so we must have control over them to execute the
> >> exact sequence.
> > 
> > Right, let's keep them mandatory. If we later have to make them optional
> > for a board that pulls one of those signals up (assuming this can work at
> > all) we'll revisit the bindings.
> 
> Ok.
> 
> >>>> +- vdddo-supply: Chip digital IO regulator.
> >>>> +- vdda-supply: Chip analog regulator.
> >>>> +- vddd-supply: Chip digital core regulator.
> >>>> +
> >>>> +The device node must contain one 'port' child node for its digital
> >>>> output
> >>>> +video port, in accordance with the video interface bindings defined in
> >>>> +Documentation/devicetree/bindings/media/video-interfaces.txt.
> >>>> +
> >>>> +Example:
> >>>> +
> >>>> +	&i2c1 {
> >>>> +		...
> >>>> +
> >>>> +		ov5645: ov5645@78 {
> >>>> +			compatible = "ovti,ov5645";
> >>>> +			reg = <0x78>;
> >>>> +
> >>>> +			enable-gpios = <&gpio1 6 GPIO_ACTIVE_HIGH>;
> >>>> +			reset-gpios = <&gpio5 20 GPIO_ACTIVE_LOW>;
> >>>> +			pinctrl-names = "default";
> >>>> +			pinctrl-0 = <&camera_rear_default>;
> >>>> +
> >>>> +			clocks = <&clks 200>;
> >>>> +			clock-names = "xclk";
> >>>> +			clock-frequency = <23880000>;
> >>>> +
> >>>> +			vdddo-supply = <&camera_dovdd_1v8>;
> >>>> +			vdda-supply = <&camera_avdd_2v8>;
> >>>> +			vddd-supply = <&camera_dvdd_1v2>;
> >>>> +
> >>>> +			port {
> >>>> +				ov5645_ep: endpoint {
> >>>> +					clock-lanes = <1>;
> >>>> +					data-lanes = <0 2>;
> >>>> +					remote-endpoint = <&csi0_ep>;
> >>>> +				};
> >>>> +			};
> >>>> +		};
> >>>> +	};

-- 
Regards,

Laurent Pinchart