Re: [PATCH v1 2/8] dt-bindings: iio: dac: maxim,ds4424: add maxim,rfs-ohms property
From: Oleksij Rempel <o.rempel@pengutronix.de>
Date: 2026-01-23 10:03:41
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linux-iio, lkml
On Fri, Jan 23, 2026 at 09:28:19AM +0000, Jonathan Cameron wrote:
On Mon, 19 Jan 2026 18:27:52 +0000 Conor Dooley [off-list ref] wrote:quoted
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?
No, this DAC controls the current. The current range is application specific and defined by the load resistors. Is it better to not provide scale if this information not available, guessing it will make things worse and potentially damage some HW.
DT binding should require it.
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