From patchwork Wed Jan 13 18:55:02 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jacopo Mondi X-Patchwork-Id: 12017659 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 4D739C43331 for ; Wed, 13 Jan 2021 18:55:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 17EDD2250E for ; Wed, 13 Jan 2021 18:55:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728583AbhAMSzu (ORCPT ); Wed, 13 Jan 2021 13:55:50 -0500 Received: from relay5-d.mail.gandi.net ([217.70.183.197]:55347 "EHLO relay5-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728552AbhAMSzu (ORCPT ); Wed, 13 Jan 2021 13:55:50 -0500 X-Originating-IP: 93.61.96.190 Received: from uno.LocalDomain (93-61-96-190.ip145.fastwebnet.it [93.61.96.190]) (Authenticated sender: jacopo@jmondi.org) by relay5-d.mail.gandi.net (Postfix) with ESMTPSA id ACAF41C000E; Wed, 13 Jan 2021 18:55:05 +0000 (UTC) From: Jacopo Mondi To: kieran.bingham+renesas@ideasonboard.com, laurent.pinchart+renesas@ideasonboard.com, niklas.soderlund+renesas@ragnatech.se, geert@linux-m68k.org Cc: Jacopo Mondi , linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org, Hyun Kwon , Manivannan Sadhasivam , sergei.shtylyov@gmail.com, Rob Herring , Laurent Pinchart Subject: [PATCH v7 4/7] dt-bindings: media: max9286: Document 'maxim,reverse-channel-microvolt' Date: Wed, 13 Jan 2021 19:55:02 +0100 Message-Id: <20210113185506.119808-5-jacopo+renesas@jmondi.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210113185506.119808-1-jacopo+renesas@jmondi.org> References: <20210113185506.119808-1-jacopo+renesas@jmondi.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Document the 'reverse-channel-microvolt' vendor property in the bindings document of the max9286 driver. The newly introduced property allows to specifying the initial configuration of the GMSL reverse control channel to accommodate remote serializers pre-programmed with the high threshold power supply noise immunity enabled. Reviewed-by: Rob Herring Reviewed-by: Laurent Pinchart Reviewed-by: Kieran Bingham Signed-off-by: Jacopo Mondi --- .../bindings/media/i2c/maxim,max9286.yaml | 22 +++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml b/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml index 68ee8c7d9e79..1406236e37ef 100644 --- a/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml +++ b/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml @@ -50,6 +50,26 @@ properties: '#gpio-cells': const: 2 + maxim,reverse-channel-microvolt: + minimum: 30000 + maximum: 200000 + default: 170000 + description: | + Initial amplitude of the reverse control channel, in micro volts. + + The initial amplitude shall be adjusted to a value compatible with the + configuration of the connected remote serializer. + + Some camera modules (for example RDACM20) include an on-board MCU that + pre-programs the embedded serializer with power supply noise immunity + (high-threshold) enabled. A typical value of the deserializer's reverse + channel amplitude to communicate with pre-programmed serializers is + 170000 micro volts. + + A typical value for the reverse channel amplitude to communicate with + a remote serializer whose high-threshold noise immunity is not enabled + is 100000 micro volts + ports: type: object description: | @@ -242,6 +262,8 @@ examples: gpio-controller; #gpio-cells = <2>; + maxim,reverse-channel-microvolt = <170000>; + ports { #address-cells = <1>; #size-cells = <0>;