Re: [PATCH v2 1/7] dt-bindings: iio: BU27034 => BU27034ANUC

Jonathan Cameron
2024-07-07T13:05:43Z

On Fri, 5 Jul 2024 13:54:12 +0300
Matti Vaittinen <mazziesaccount@gmail.com> wrote:

> The BU27034NUC was cancelled before it entered mass production. It was
> replaced by a new variant BU27034ANUC (note, added 'A'). The new
> variant gained a few significant changes, like removal of the 3.rd data
> channel and dropping some of the gain settings. This means that, from
> software point of view these ICs are incompatible. Lux calculation based
> on the data from the sensors needs to be done differently, and on the
> BU27034ANUC the channel 3 data is missing. Also, the gain setting
> differencies matter.
>
> Unfortunately, the identification register was not changed so there is no
> safe way for the software to distinguish the variants.
>
> According to the ROHM HQ engineers, the old BU27034NUC should not be
> encountered in the wild. Hence it makes sense to remove the support for
> the old BU27034NUC and add support for the new BU27034ANUC. Change the
> compatible in order to not load the incompatible old driver for new sensor
> (or, if someone had the old sensor, the new driver for it).
>
> Drop the compatible for old sensor which should not be in the wild and
> add a new compatible for the new model with accurate model suffix
> 'anuc'.
>
> Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Rename indeed makes sense. One minor, 'whilst you are here' comment inline.

>
> ---
> A patch renaming the file according to the new compatible will follow.
> If renaming is not needed or appropriate, that patch can be dropped.
>
> Revision history:
> v2: New patch
> ---
> .../devicetree/bindings/iio/light/rohm,bu27034.yaml | 9 ++++-----
> 1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/iio/light/rohm,bu27034.yaml b/Documentation/devicetree/bindings/iio/light/rohm,bu27034.yaml
> index 30a109a1bf3b..535bd18348ac 100644
> --- a/Documentation/devicetree/bindings/iio/light/rohm,bu27034.yaml
> +++ b/Documentation/devicetree/bindings/iio/light/rohm,bu27034.yaml
> @@ -4,20 +4,19 @@
> $id: http://devicetree.org/schemas/iio/light/rohm,bu27034.yaml#
> $schema: http://devicetree.org/meta-schemas/core.yaml#
>
> -title: ROHM BU27034 ambient light sensor
> +title: ROHM BU27034ANUC ambient light sensor
>
> maintainers:
> - Matti Vaittinen <mazziesaccount@gmail.com>
>
> description: |
> - ROHM BU27034 is an ambient light sesnor with 3 channels and 3 photo diodes
> + ROHM BU27034ANUC is an ambient light sesnor with 2 channels and 2 photo diodes

sensor

> capable of detecting a very wide range of illuminance. Typical application
> is adjusting LCD and backlight power of TVs and mobile phones.
> - https://fscdn.rohm.com/en/products/databook/datasheet/ic/sensor/light/bu27034nuc-e.pdf
>
> properties:
> compatible:
> - const: rohm,bu27034
> + const: rohm,bu27034anuc
>
> reg:
> maxItems: 1
> @@ -37,7 +36,7 @@ examples:
> #size-cells = <0>;
>
> light-sensor@38 {
> - compatible = "rohm,bu27034";
> + compatible = "rohm,bu27034anuc";
> reg = <0x38>;
> vdd-supply = <&vdd>;
> };