From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 48E81C433E7 for ; Mon, 12 Oct 2020 14:41:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E5642072D for ; Mon, 12 Oct 2020 14:41:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389054AbgJLOlO (ORCPT ); Mon, 12 Oct 2020 10:41:14 -0400 Received: from lhrrgout.huawei.com ([185.176.76.210]:2974 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2387930AbgJLOlO (ORCPT ); Mon, 12 Oct 2020 10:41:14 -0400 Received: from lhreml710-chm.china.huawei.com (unknown [172.18.7.107]) by Forcepoint Email with ESMTP id 64442A59CF58AD0B4C75; Mon, 12 Oct 2020 15:41:10 +0100 (IST) Received: from localhost (10.52.126.145) by lhreml710-chm.china.huawei.com (10.201.108.61) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1913.5; Mon, 12 Oct 2020 15:41:10 +0100 Date: Mon, 12 Oct 2020 15:39:23 +0100 From: Jonathan Cameron To: Tomas Novotny CC: Jonathan Cameron , , "Rob Herring" Subject: Re: [PATCH 20/29] dt-bindings:iio:dac:microchip,mcp4725 yaml conversion Message-ID: <20201012143923.000023d8@Huawei.com> In-Reply-To: <20201012160230.7a0c5eb8@tomas.local.tbs-biometrics.cz> References: <20201011170749.243680-1-jic23@kernel.org> <20201011170749.243680-21-jic23@kernel.org> <20201012160230.7a0c5eb8@tomas.local.tbs-biometrics.cz> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; i686-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.52.126.145] X-ClientProxiedBy: lhreml750-chm.china.huawei.com (10.201.108.200) To lhreml710-chm.china.huawei.com (10.201.108.61) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org On Mon, 12 Oct 2020 16:02:30 +0200 Tomas Novotny wrote: > Hi Jonathan, > > On Sun, 11 Oct 2020 18:07:40 +0100 > Jonathan Cameron wrote: > > > From: Jonathan Cameron > > > > I'm not sure vdd-supply absolutely has to be provided if vref-supply > > is, but as the previous binding docs stated it was required it seems > > reasonable to leave it as such. > > Good catch. Vdd is useless on MCP4726 if Vref is specified. The driver > requires Vdd... The driver will get the regulator but as it's not via an optional call it the regulator core will provide a stub regulator. If the ref regulator is present, all that will happen with vdd is a regulator_enable() call which is fine with a stub regulator (it's a noop). So we should be good to update the binding to specify the requirement. Perhaps it's one to do as a follow up patch? Given any existing DT must be providing that regulator, there is no rush for us to fix it :) > > How to proceed there? > > Thanks, > > Tomas > > > Signed-off-by: Jonathan Cameron > > Cc: Tomas Novotny > > --- > > .../devicetree/bindings/iio/dac/mcp4725.txt | 35 --------- > > .../bindings/iio/dac/microchip,mcp4725.yaml | 71 +++++++++++++++++++ > > 2 files changed, 71 insertions(+), 35 deletions(-) > > > > diff --git a/Documentation/devicetree/bindings/iio/dac/mcp4725.txt b/Documentation/devicetree/bindings/iio/dac/mcp4725.txt > > deleted file mode 100644 > > index 1bc6c093fbfe..000000000000 > > --- a/Documentation/devicetree/bindings/iio/dac/mcp4725.txt > > +++ /dev/null > > @@ -1,35 +0,0 @@ > > -Microchip mcp4725 and mcp4726 DAC device driver > > - > > -Required properties: > > - - compatible: Must be "microchip,mcp4725" or "microchip,mcp4726" > > - - reg: Should contain the DAC I2C address > > - - vdd-supply: Phandle to the Vdd power supply. This supply is used as a > > - voltage reference on mcp4725. It is used as a voltage reference on > > - mcp4726 if there is no vref-supply specified. > > - > > -Optional properties (valid only for mcp4726): > > - - vref-supply: Optional phandle to the Vref power supply. Vref pin is > > - used as a voltage reference when this supply is specified. > > - - microchip,vref-buffered: Boolean to enable buffering of the external > > - Vref pin. This boolean is not valid without the vref-supply. Quoting > > - the datasheet: This is offered in cases where the reference voltage > > - does not have the current capability not to drop its voltage when > > - connected to the internal resistor ladder circuit. > > - > > -Examples: > > - > > - /* simple mcp4725 */ > > - mcp4725@60 { > > - compatible = "microchip,mcp4725"; > > - reg = <0x60>; > > - vdd-supply = <&vdac_vdd>; > > - }; > > - > > - /* mcp4726 with the buffered external reference voltage */ > > - mcp4726@60 { > > - compatible = "microchip,mcp4726"; > > - reg = <0x60>; > > - vdd-supply = <&vdac_vdd>; > > - vref-supply = <&vdac_vref>; > > - microchip,vref-buffered; > > - }; > > diff --git a/Documentation/devicetree/bindings/iio/dac/microchip,mcp4725.yaml b/Documentation/devicetree/bindings/iio/dac/microchip,mcp4725.yaml > > new file mode 100644 > > index 000000000000..271998610ceb > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/iio/dac/microchip,mcp4725.yaml > > @@ -0,0 +1,71 @@ > > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) > > +%YAML 1.2 > > +--- > > +$id: http://devicetree.org/schemas/iio/dac/microchip,mcp4725.yaml# > > +$schema: http://devicetree.org/meta-schemas/core.yaml# > > + > > +title: Microchip mcp4725 and mcp4726 DAC > > + > > +maintainers: > > + - Tomas Novotny > > + > > +properties: > > + compatible: > > + enum: > > + - microchip,mcp4725 > > + - microchip,mcp4726 > > + > > + reg: > > + maxItems: 1 > > + > > + vdd-supply: > > + description: | > > + Provides both power and acts as the reference supply on the mcp4725. > > + For the mcp4726 it will be used as the reference voltage if vref-supply > > + is not provided. > > + > > + vref-supply: > > + description: > > + Vref pin is used as a voltage reference when this supply is specified. > > + > > + microchip,vref-buffered: > > + type: boolean > > + description: | > > + Enable buffering of the external Vref pin. This boolean is not valid > > + without the vref-supply. Quoting the datasheet: This is offered in > > + cases where the reference voltage does not have the current > > + capability not to drop its voltage when connected to the internal > > + resistor ladder circuit. > > + > > +allOf: > > + - if: > > + not: > > + properties: > > + compatible: > > + contains: > > + const: microchip,mcp4726 > > + then: > > + properties: > > + vref-supply: false > > + microchip,vref-buffered: false > > + > > +required: > > + - compatible > > + - reg > > + - vdd-supply > > + > > +additionalProperties: false > > + > > +examples: > > + - | > > + i2c { > > + #address-cells = <1>; > > + #size-cells = <0>; > > + > > + mcp4725@60 { > > + compatible = "microchip,mcp4725"; > > + reg = <0x60>; > > + vdd-supply = <&vdac_vdd>; > > + }; > > + }; > > +...