Re: [PATCH v2 2/2] hwmon: (sht4x) Add device tree match table and document it

[David Mosberger-Tang <davidm@egauge.net>]

On Sat, 2021-11-20 at 13:12 -0800, Guenter Roeck wrote:
> On 11/20/21 12:40 PM, David Mosberger-Tang wrote:
> > This patch enables automatic loading of the sht4x module via a device
> > tree table entry.
> > 
> > Signed-off-by: David Mosberger-Tang <davidm@egauge.net>
> > ---
> >   .../bindings/hwmon/sensirion,sht4x.yaml       | 50 +++++++++++++++++++
> >   drivers/hwmon/sht4x.c                         |  7 +++
> 
> This needs to be two separate patches, one the devicetree change and the other
> the source code change. DT maintainers need to be copied on the devicetree
> patch.

Isn't that going to be confusing if one but not the other patch makes
it into a repository?  Either you end up with an undocumented device
tree property or you end up with documentation for an unsupported
property.

> Also, please consider adding the device to trivial-devices.yaml instead since
> there are no special bindings.

I didn't know it existed.  Sure, that's much easier.

  --david

> Thanks,
> Guenter
> 
> >   2 files changed, 57 insertions(+)
> >   create mode 100644 Documentation/devicetree/bindings/hwmon/sensirion,sht4x.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/hwmon/sensirion,sht4x.yaml b/Documentation/devicetree/bindings/hwmon/sensirion,sht4x.yaml
> > new file mode 100644
> > index 000000000000..588c2e37b035
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/hwmon/sensirion,sht4x.yaml
> > @@ -0,0 +1,50 @@
> > +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/hwmon/sensirion,sht4x.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Sensirion SHT4x Humidity and Temperature Sensor IC
> > +
> > +maintainers:
> > +  - Navin Sankar Velliangiri navin@linumiz.com
> > +
> > +description: |
> > +  The SHT4x is a high-accuracy digital humidity and temperature sensor
> > +  designed especially for battery-driven high-volume consumer
> > +  electronics applications.  For further information refere to
> > +  Documentation/hwmon/sht4x.rst
> > +
> > +  This binding document describes the binding for the hardware monitor
> > +  portion of the driver.
> > +
> > +properties:
> > +  compatible:
> > +    enum:
> > +      - sensirion,sht4x
> > +
> > +  reg:
> > +    const: 0x44
> > +    description:
> > +      The I2c base address of the SHT4x.  0x44 for all chip versions
> > +      except for SHT41-BD1B, where it is 0x45.
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +    i2c {
> > +      #address-cells = <1>;
> > +      #size-cells = <0>;
> > +      clock-frequency = <400000>;
> > +
> > +      sht4x@44 {
> > +        compatible = "sensirion,sht4x";
> > +        reg = <0x44>;
> > +      };
> > +    };
> > +...
> > diff --git a/drivers/hwmon/sht4x.c b/drivers/hwmon/sht4x.c
> > index 3415d7a0e0fc..6e53d81e32d4 100644
> > --- a/drivers/hwmon/sht4x.c
> > +++ b/drivers/hwmon/sht4x.c
> > @@ -281,9 +281,16 @@ static const struct i2c_device_id sht4x_id[] = {
> >   };
> >   MODULE_DEVICE_TABLE(i2c, sht4x_id);
> >   
> > +static const struct of_device_id sht4x_of_match[] = {
> > +	{ .compatible = "sensirion,sht4x" },
> > +	{ }
> > +};
> > +MODULE_DEVICE_TABLE(of, sht4x_of_match);
> > +
> >   static struct i2c_driver sht4x_driver = {
> >   	.driver = {
> >   		.name = "sht4x",
> > +		.of_match_table = sht4x_of_match
> >   	},
> >   	.probe		= sht4x_probe,
> >   	.id_table	= sht4x_id,
> >