From patchwork Tue Dec 15 17:09:54 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jacopo Mondi X-Patchwork-Id: 344700 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, USER_AGENT_GIT 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 7EA0DC4361B for ; Tue, 15 Dec 2020 17:11:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 320432251E for ; Tue, 15 Dec 2020 17:11:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729768AbgLORKt (ORCPT ); Tue, 15 Dec 2020 12:10:49 -0500 Received: from relay5-d.mail.gandi.net ([217.70.183.197]:44731 "EHLO relay5-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728206AbgLORKl (ORCPT ); Tue, 15 Dec 2020 12:10:41 -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 relay5-d.mail.gandi.net (Postfix) with ESMTPSA id 456C71C000A; Tue, 15 Dec 2020 17:09:57 +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 v6 2/5] dt-bindings: media: max9286: Document 'maxim, reverse-channel-microvolt' Date: Tue, 15 Dec 2020 18:09:54 +0100 Message-Id: <20201215170957.92761-3-jacopo+renesas@jmondi.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201215170957.92761-1-jacopo+renesas@jmondi.org> References: <20201215170957.92761-1-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: Kieran Bingham Signed-off-by: Jacopo Mondi Reviewed-by: Laurent Pinchart --- v5->v6: - Use standard unit suffix 'microvolt' for the custom property - Drop '$ref' as according to 'example-schema.yaml': "Vendor specific properties having a standard unit suffix don't need a type." --- .../bindings/media/i2c/maxim,max9286.yaml | 23 +++++++++++++++++++ 1 file changed, 23 insertions(+) -- 2.29.2 diff --git a/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml b/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml index 9ea827092fdd..b22ba3e0db4a 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,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: | @@ -221,6 +241,7 @@ required: - ports - i2c-mux - gpio-controller + - maxim,reverse-channel-microvolt additionalProperties: false @@ -243,6 +264,8 @@ examples: gpio-controller; #gpio-cells = <2>; + maxim,reverse-channel-microvolt = <170000>; + ports { #address-cells = <1>; #size-cells = <0>;