From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 25F4E3C4576; Wed, 20 May 2026 10:01:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779271320; cv=none; b=oQG9sohhU6U3OK2SQVz6CifmOfKoAOPfTnn622uHHe9L4yJyr6tHbb+BWw/5DKuWeQS+K33D4eRjaTBzMoSdyzOb+kWNuDdFsqeTrPlA7fXQCiDYMfKHNUffgeFmCmJdYhRDDiCQWAK9M4ABuyshGvKJsh8F4mt3JVZnDZpjY/M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779271320; c=relaxed/simple; bh=qKMywVhaNw1tNHLhSK5k0a7DjEgI8FfNy9d3GoQjxis=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=OVDLUWKR9gFyfI/P6Obu+I3aeuxhiN+9k2tiVH5Ge09XorLP9NDTIf5MuXHMsooApiZzosqY/2Z+Wp0/o+7UW5h0SL+pNIcJSBNj7xs1HkzFwVvygRb33l1V74MWRZr3LmQIQrmVCbywa52cpi6fK7q21H192EiwWZMwAoJkMm8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XXVHq6ej; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XXVHq6ej" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AE1511F000E9; Wed, 20 May 2026 10:01:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779271318; bh=ND4Dzr/UsDZIl/Bhjbr0HOI2CU59MYoi8lOgRpb7/dg=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=XXVHq6ej+P3wxX8LJol8gghobYkIYzYi36g2WlGkBJRLMzIZvUo/xzlneSf+l7up1 sxXYZWQdcTvTgNyxz2ycKnIsItolNDPZx3MLz9NyDv1FPwNK4xTRaif4ecRSd/Zo9Y QDO38YqYm3ah1IbpPPnXjBDv88vUoUUCi3WjrEqD7j7XpyuhsQkUCewXgUh1LCVd+e suK5pugHoERES/9mxbwGv7tKdUbmiwmiDscjTKsDVmplrKBC3V+rPZbYrscC1zHkSa B1tTieB91JHnV4Qmgxqo2/B9qoQRrtqyers8rTKJF47XQHPXJDY6yuDiGE5mMhZdR7 DXgqpqw+R33sw== Date: Wed, 20 May 2026 11:01:49 +0100 From: Jonathan Cameron To: Piyush Patle Cc: ak@it-klinger.de, andriy.shevchenko@linux.intel.com, dlechner@baylibre.com, nuno.sa@analog.com, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v8 v8 02/11] dt-bindings: iio: adc: hx711: add VSUP supply property Message-ID: <20260520110149.4086c934@jic23-huawei> In-Reply-To: References: <20260511174342.123820-1-piyushpatle228@gmail.com> <20260511174342.123820-3-piyushpatle228@gmail.com> <20260512130622.1f3f4d08@jic23-huawei> <20260512130809.5ab5eb90@jic23-huawei> X-Mailer: Claws Mail 4.4.0 (GTK 3.24.52; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Tue, 19 May 2026 02:47:44 +0530 Piyush Patle wrote: > On Tue, May 12, 2026 at 5:38=E2=80=AFPM Jonathan Cameron wrote: > > > > On Tue, 12 May 2026 13:06:22 +0100 > > Jonathan Cameron wrote: > > =20 > > > On Mon, 11 May 2026 23:13:27 +0530 > > > Piyush Patle wrote: > > > =20 > > > > Document the optional VSUP supply used by the HX711 on-chip regulat= or. > > > > > > > > Signed-off-by: Piyush Patle > > > > Reviewed-by: Andy Shevchenko > > > > Acked-by: Conor Dooley > > > > --- =20 > > > > > > I got curious given the driver doesn't yet turn this on and wanted > > > to just sanity check it via a datasheet. > > > > > > Why are we including this one but not dvdd-supply? The suggested > > > wiring does connect them to the same supply but it's external to the > > > chip so in theory they might not be. Curiously dvdd supply is allowed > > > to be 0.1 V lower than vsup-supply. =20 > The HX711 does have a DVDD pin, but it is the output of the internal > LDO and is normally just bypassed to ground. VSUP is the rail supplied by > the board, so that was the one I documented here. Not according to the diagram in figure 1 of https://cdn.sparkfun.com/datasheets/Sensors/ForceFlex/hx711_english.pdf That clearly shows DVDD connected to same input supply as VSUP. There is a note in there to say that if the internal regulator is not used VSUP should always be connected to the higher of DVDD and AVDD. > That said, dvdd-supply is already allowed for HX711 nodes by patch 04, > as only vref-supply is forbidden for HX711. So the binding does not block > a board from describing DVDD if needed. Agreed you add it later, but it should be in this patch that is adding miss= ing dt-bindings for the existing part. > The driver does not use DVDD for HX711 today, but explicit support can be > added later if there is a real user for it. We should make dt-bindings complete. That doesn't mean the driver has to use them though! Hence I'd like to see dvdd added in this patch rather than later with a statement of why it is used for the hx711. As far as I can tell it should really be required and documented as a bug in the original binding. Jonathan > > > > I should have said, given there is nothing wrong with what you have here > > and the above is a possible additional change - applied to the testing > > branch of iio.git. > > > > Thanks, > > > > Jonathan > > =20 > Thanks for applying patches 01-03. > > > =20 > > > > Documentation/devicetree/bindings/iio/adc/avia-hx711.yaml | 4 ++++ > > > > 1 file changed, 4 insertions(+) > > > > > > > > diff --git a/Documentation/devicetree/bindings/iio/adc/avia-hx711.y= aml b/Documentation/devicetree/bindings/iio/adc/avia-hx711.yaml > > > > index 1ea60dff98d5..a8eaa1f18de5 100644 > > > > --- a/Documentation/devicetree/bindings/iio/adc/avia-hx711.yaml > > > > +++ b/Documentation/devicetree/bindings/iio/adc/avia-hx711.yaml > > > > @@ -33,6 +33,10 @@ properties: > > > > description: > > > > Analog supply voltage (AVDD). > > > > > > > > + vsup-supply: > > > > + description: > > > > + Supply voltage for the on-chip regulator (VSUP). > > > > + > > > > clock-frequency: > > > > description: > > > > Controls the SCK bit-bang timing. The value is used to deriv= e the =20 > > > =20 > > =20 >=20