On Mon, 19 Jan 2026 18:27:52 +0000
Conor Dooley [off-list ref] wrote:

On Mon, Jan 19, 2026 at 07:24:18PM +0100, Oleksij Rempel wrote:

quoted

Introduce the 'maxim,rfs-ohms' property. The full-scale output current
of these DACs is determined by external resistors (Rfs) connected to
the FS pins. The driver requires the physical resistance values to
calculate the correct current scale (Amps per step) for the IIO
subsystem.

Keep it optional to avoid forcing updates of existing DTs; without it
the driver cannot derive a correct IIO scale.  

I don't really follow the logic here, if the driver doesn't work
properly without it, shouldn't it be a required property even if that
means existing devicetrees get new warnings? Warnings are preferable to
the drivers malfunctioning on those devices, after all!

Agreed. The driver can paper over holes or I guess we could provide a default
if the datasheet has some reference value or similar?  

DT binding should require it.

quoted

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 .../devicetree/bindings/iio/dac/maxim,ds4424.yaml     | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/dac/maxim,ds4424.yaml b/Documentation/devicetree/bindings/iio/dac/maxim,ds4424.yaml
index efe63e6cb55d..b7af8464a4fc 100644
--- a/Documentation/devicetree/bindings/iio/dac/maxim,ds4424.yaml
+++ b/Documentation/devicetree/bindings/iio/dac/maxim,ds4424.yaml

@@ -27,6 +27,17 @@ properties:
 
   vcc-supply: true
 
+  maxim,rfs-ohms:
+    description: |
+      Array of resistance values in Ohms for the external Rfs resistors
+      connected to the FS pins.
+      - For DS44x2 (2 channels): 2 values required.
+      - For DS44x4 (4 channels): 4 values required.
+      Typical values range from 40000 (40 kOhm) to 160000 (160 kOhm).
+    minItems: 2
+    maxItems: 4
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+
 required:
   - compatible
   - reg

-- 
2.47.3