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

Matti Vaittinen
2024-07-05T10:54:19Z

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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>

---
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
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>;
};