From patchwork Thu Jan 14 17:04:26 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jacopo Mondi X-Patchwork-Id: 363181 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 D1AF1C433E0 for ; Thu, 14 Jan 2021 17:06:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A3B1523B52 for ; Thu, 14 Jan 2021 17:06:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727802AbhANRFQ (ORCPT ); Thu, 14 Jan 2021 12:05:16 -0500 Received: from relay2-d.mail.gandi.net ([217.70.183.194]:59523 "EHLO relay2-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725854AbhANRFP (ORCPT ); Thu, 14 Jan 2021 12:05:15 -0500 X-Originating-IP: 93.34.118.233 Received: from uno.lan (93-34-118-233.ip49.fastwebnet.it [93.34.118.233]) (Authenticated sender: jacopo@jmondi.org) by relay2-d.mail.gandi.net (Postfix) with ESMTPSA id 19FCC40007; Thu, 14 Jan 2021 17:04:30 +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 v8 2/5] dt-bindings: media: max9286: Document 'maxim, reverse-channel-microvolt' Date: Thu, 14 Jan 2021 18:04:26 +0100 Message-Id: <20210114170429.139762-3-jacopo+renesas@jmondi.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210114170429.139762-1-jacopo+renesas@jmondi.org> References: <20210114170429.139762-1-jacopo+renesas@jmondi.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Document the 'maxim,reverse-channel-microvolt' vendor property in the bindings document of the max9286 driver. The newly introduced property allows to specify 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>;