From patchwork Mon Nov 16 13:52:59 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jacopo Mondi X-Patchwork-Id: 324867 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=-12.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, 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 7E208C63798 for ; Mon, 16 Nov 2020 13:53:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 533E2222B9 for ; Mon, 16 Nov 2020 13:53:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729575AbgKPNxb (ORCPT ); Mon, 16 Nov 2020 08:53:31 -0500 Received: from relay2-d.mail.gandi.net ([217.70.183.194]:37101 "EHLO relay2-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726286AbgKPNxb (ORCPT ); Mon, 16 Nov 2020 08:53:31 -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 5B9514000B; Mon, 16 Nov 2020 13:53:26 +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, robh@kernel.org, devicetree@vger.kernel.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 Subject: [PATCH v5 2/8] dt-bindings: media: max9286: Document 'maxim, initial-reverse-channel-mV' Date: Mon, 16 Nov 2020 14:52:59 +0100 Message-Id: <20201116135305.81319-3-jacopo+renesas@jmondi.org> X-Mailer: git-send-email 2.29.1 In-Reply-To: <20201116135305.81319-1-jacopo+renesas@jmondi.org> References: <20201116135305.81319-1-jacopo+renesas@jmondi.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Document the 'initial-reverse-channel-mV' 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: Kieran Bingham Signed-off-by: Jacopo Mondi --- .../bindings/media/i2c/maxim,max9286.yaml | 23 +++++++++++++++++++ 1 file changed, 23 insertions(+) -- 2.29.1 diff --git a/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml b/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml index 9ea827092fdd..f61234d204fa 100644 --- a/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml +++ b/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml @@ -51,6 +51,26 @@ properties: '#gpio-cells': const: 2 + maxim,initial-reverse-channel-mV: + $ref: '/schemas/types.yaml#/definitions/uint32' + minimum: 30 + maximum: 200 + default: 170 + description: | + Initial amplitude of the reverse control channel, in millivolts. + + 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 170mV. + + A typical value for the reverse channel amplitude to communicate with + a remote serializer whose high-threshold noise immunity is not enabled + is 100mV. + ports: type: object description: | @@ -221,6 +241,7 @@ required: - ports - i2c-mux - gpio-controller + - maxim,initial-reverse-channel-mV additionalProperties: false @@ -243,6 +264,8 @@ examples: gpio-controller; #gpio-cells = <2>; + maxim,initial-reverse-channel-mV = <170>; + ports { #address-cells = <1>; #size-cells = <0>;