Re: [PATCH v2 1/8] media: dt-bindings: i2c: Document ov5670

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

Hi Sakari,

On Tue, Mar 15, 2022 at 09:59:17AM +0200, Sakari Ailus wrote:
> On Tue, Mar 15, 2022 at 08:32:58AM +0100, Krzysztof Kozlowski wrote:
> > On 14/03/2022 17:27, Jacopo Mondi wrote:
> > > Provide the bindings documentation for Omnivision OV5670 image sensor.
> > > 
> > > Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
> > > 
> > > ---
> > > v1->v2 (comments from Krzysztof)
> > > 
> > > - Rename to include manufacturer name
> > > - Add entry to MAINTAINERS
> > > - Add maxItems: to -gpios properties
> > > - Use common clock properties
> > > - Use enum: [1, 2] for data lanes
> > > - Fix whitespace issue in example
> > > ---
> > > 
> > >  .../bindings/media/i2c/ovti,ov5670.yaml       | 99 +++++++++++++++++++
> > >  MAINTAINERS                                   |  1 +
> > >  2 files changed, 100 insertions(+)
> > >  create mode 100644 Documentation/devicetree/bindings/media/i2c/ovti,ov5670.yaml
> > > 
> > > diff --git a/Documentation/devicetree/bindings/media/i2c/ovti,ov5670.yaml b/Documentation/devicetree/bindings/media/i2c/ovti,ov5670.yaml
> > > new file mode 100644
> > > index 000000000000..73cf72203f17
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/media/i2c/ovti,ov5670.yaml
> > > @@ -0,0 +1,99 @@
> > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > > +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/media/i2c/ovti,ov5670.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: Omnivision OV5670 5 Megapixels raw image sensor
> > > +
> > > +maintainers:
> > > +  - Jacopo Mondi <jacopo@jmondi.org>
> > > +
> > > +description: |-
> > > +  The OV5670 is a 5 Megapixels raw image sensor which provides images in 10-bits
> > > +  RAW BGGR Bayer format on a 2 data lanes MIPI CSI-2 serial interface and is
> > > +  controlled through an I2C compatible control bus.
> > > +
> > > +properties:
> > > +  compatible:
> > > +    const: ovti,ov5670
> > > +
> > > +  reg:
> > > +    maxItems: 1
> > > +
> > > +  assigned-clocks: true
> > > +  assigned-clock-parents: true
> > > +  assigned-clock-rates: true
> > 
> > You should not need these. These are coming with schema. You can add
> > these to example schema below and double-check.
> 
> They should probably be required actually.

Why so ?

> > > +
> > > +  clocks:
> > > +    description: System clock. From 6 to 27 MHz.
> > > +    maxItems: 1
> > > +
> > > +  pwdn-gpios:
> > > +    description: Reference to the GPIO connected to the PWDNB pin. Active low.
> > 
> > This does not look like a standard property, so you need a vendor prefix.
> 
> The similarly named property exists elsewhere. I wouldn't use a vendor
> prefix, also for the reason that the functionality is quite common. I guess
> alternative name would be possible, too --- "shutdown" seems to be more
> common.

There's a desire to standardize GPIO names ("reset" and "enable" being
the two most common candidates), but I'm not aware of an official list
of standard names. Have I missed it ?

In this case, I'd use powerdown-gpios, as it's more common than
pwdn-gpios (used in 21 bindings, compared to 2 for pwdn-gpios).

-- 
Regards,

Laurent Pinchart