linux-kernel - Re: [PATCH 2/2] dt-bindings: iio: magnetometer: document Infineon TLV493D 3D Magnetic sensor

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aIg5_x4UMLjRk4dn@dixit>
Date: Tue, 29 Jul 2025 08:33:27 +0530
From: Dixit Parmar <dixitparmar19@...il.com>
To: David Lechner <dlechner@...libre.com>
Cc: Jonathan Cameron <jic23@...nel.org>,
	Nuno Sá <nuno.sa@...log.com>,
	Andy Shevchenko <andy@...nel.org>, Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>, linux-kernel@...r.kernel.org,
	linux-iio@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH 2/2] dt-bindings: iio: magnetometer: document Infineon
 TLV493D 3D Magnetic sensor

On Sat, Jul 26, 2025 at 03:43:56PM -0500, David Lechner wrote:
> On 7/26/25 4:37 AM, Dixit Parmar wrote:
> > Document the bindings for Infineon TLV493D Low-Power 3D Magnetic Sensor
> > controlled by I2C interface. Main applications includes joysticks, control
> > elements (white goods, multifunction knops), or electric meters (anti
> > tampering).
> > 
> > The device can be configured in to different operating modes by optional
> > device-tree "mode" property. Also, the temperature sensing part requires
> > raw offset captured at 25°C and that can be specified by "temp-offset"
> > optional device-tree property.
> > 
> > Datasheet: https://www.infineon.com/assets/row/public/documents/24/49/infineon-tlv493d-a1b6-datasheet-en.pdf
> > 
> > Signed-off-by: Dixit Parmar <dixitparmar19@...il.com>
> > ---
> >  .../iio/magnetometer/infineon,tlv493d.yaml         | 57 ++++++++++++++++++++++
> >  1 file changed, 57 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/iio/magnetometer/infineon,tlv493d.yaml b/Documentation/devicetree/bindings/iio/magnetometer/infineon,tlv493d.yaml
> > new file mode 100644
> > index 000000000000..0442cf41503b
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/magnetometer/infineon,tlv493d.yaml
> > @@ -0,0 +1,57 @@
> > +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/iio/magnetometer/infineon,tlv493d.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Infineon Technologies TLV493D Low-Power 3D Magnetic Sensor
> > +
> > +maintainers:
> > +  - Dixit Parmar <dixitparmar19@...il.com>
> > +
> > +properties:
> > +  $nodename:
> > +    pattern: '^magnetometer@[0-9a-f]+$'
> > +
> > +  compatible:
> > +    const: infineon,tlv493d-a1b6
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  vdd-supply:
> > +    description: 2.8V to 3.5V supply
> 
> The SDA pin can also be a /INT signal, so we need to have an
> optional interrupts property as well.
>
Okay. Will add it.
> > +
> > +  mode:
> > +    description: Sensor operating mode. Must be one of the defined enum values.
> > +    $ref: /schemas/types.yaml#/definitions/uint32
> > +    enum:
> > +      - 0 # Power Down Mode. No measurement.
> > +      - 1 # Fast Mode
> > +      - 2 # Low-Power Mode
> > +      - 3 # Ultra Low-Power Mode
> > +      - 4 # Master Controlled Mode
> > +    default: 4
> 
> This is not the sort of thing that really belongs in a devicetree.
> We should be describing here how the chip is wired up, and only
> control how it works based on that.
> 
> If there are any wiring conditions that could affect this setting,
> they could go here. For example, if the power supply doesn't have
> enough current, then we can only operate in one of the low power
> modes. Otherwise generally we just stick to the best performing
> mode. And specifying the power down mode here really doesn't make
> sense - you could never use the sensor!
> 
Got it. Will remove it.
> > +
> > +  temp-offset:
> > +    description: Raw temperature offset at 25°C to apply before applying scale and correction.
> > +    $ref: /schemas/types.yaml#/definitions/uint32
> > +    default: 340
> 
> This is another one that likely doesn't belong in the devicetree.
> There is a standard *_calibbias attribute that can be used for
> such a calibration if needed.
> 
Its factory setting so I thought if there is any deviation from that
than we can handle it like this but as you pointed out, its not the
right way, so will stick to 340 default factory value as per the
datasheet.
> > +
> > +required:
> > +  - compatible
> > +  - reg
> 
> Power supplies are usually required.
> 
Ack.
> > +
> > +additionalProperties: false
> > +
> > +example:
> > +  - |
> > +    i2c {
> > +      #address-cells = <1>;
> > +      #size-cells = <0>;
> > +      magnetometer@5e {
> > +        compatible = "infineon,tlv493d-a1b6";
> > +        reg = <0x5e>;
> > +        vdd = <&hall_vcc>;
> > +      };
> > +    };
> > 
> 
Thanks for the review,
Dixit