From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0F0BB3EBF0C; Sun, 25 Jan 2026 10:22:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769336536; cv=none; b=m27PMsXM8otb47UEE0qcBBC8IywjpXA4Ol1h8nNy6yQOGjdsN/bvFPAWH3DS5dmtGEXfWDIihLEY5d/D+cseanF4uWR+4AxAPppoS6HCLNom2790HvAe/edEjlojdYHBOoI2i4JC0suqGVw3ybhOre2PiFg4yyCBCrnIQsb4U0U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769336536; c=relaxed/simple; bh=kPcLWa/o3rjsJMhWGoaV5KilA7EaTEWHRAIvHjLome4=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=pxrMiB0BKsppbFLGYkjavLUwyaDAgRa+2cKw9oIWVnZWbTf2eJG4B27SsvWeYoOz5cDAVPZ0tvtAT0ZXCAHXXatpIdzi+yaIhofGKNauUcmEvDUWwwCSZQgsq6c2q/a+gFe/G3pzPsWB9nP1rxL9sb1o5VlcYPzZpeozOpcbHho= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=q7mVYeeq; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="q7mVYeeq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C7C3FC4CEF1; Sun, 25 Jan 2026 10:22:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769336535; bh=kPcLWa/o3rjsJMhWGoaV5KilA7EaTEWHRAIvHjLome4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=q7mVYeeqOJ8GuQi3cJbvxZy3DkaOJA+wUm3UfAdnn2WCOOsq9sDMODT3gHaZKV8Vn jXOy+X4bket6JZG4yDp7hM7haqKXrFh9QSPnxq96IqZtcGjCj1K7aUYkUgE+cdiuzM PlWiEU0D79UB/Rp+kEN4S4aNsuAq0sqBynnfgKlfQWR+0rC17uVRhtMeYobV3J/6fC AgI12ZoXqQnvzILuv0MOgnSAVVJTnb03fnfQUMw7vxQ60VpNktfOFuB8Them2KUpaV hurCNCz4YMl2DAhWOkJBkjHGm/45roAaGHcokhE13pSJr7YMjYT/Jf/JoxT55omw5V CLofBM5M0IWqQ== Date: Sun, 25 Jan 2026 10:22:07 +0000 From: Jonathan Cameron To: Oleksij Rempel Cc: Conor Dooley , Rob Herring , Krzysztof Kozlowski , Conor Dooley , kernel@pengutronix.de, linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org, devicetree@vger.kernel.org, Andy Shevchenko , David Lechner , Nuno =?UTF-8?B?U8Oh?= , David Jander Subject: Re: [PATCH v1 2/8] dt-bindings: iio: dac: maxim,ds4424: add maxim,rfs-ohms property Message-ID: <20260125102207.37ce3501@jic23-huawei> In-Reply-To: References: <20260119182424.1660601-1-o.rempel@pengutronix.de> <20260119182424.1660601-3-o.rempel@pengutronix.de> <20260119-turbine-feminize-9dcd5c86feec@spud> <20260123092819.6ae81211@jic23-huawei> X-Mailer: Claws Mail 4.3.1 (GTK 3.24.51; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Fri, 23 Jan 2026 11:03:38 +0100 Oleksij Rempel wrote: > On Fri, Jan 23, 2026 at 09:28:19AM +0000, Jonathan Cameron wrote: > > On Mon, 19 Jan 2026 18:27:52 +0000 > > Conor Dooley wrote: > > > > > On Mon, Jan 19, 2026 at 07:24:18PM +0100, Oleksij Rempel wrote: > > > > 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. > Then does this need to be a fix on the driver side? Or are you just suggesting not proving the scale if we don't have enough info? That's fine if so. > > DT binding should require it. > > ACK