From patchwork Thu Nov 12 16:27:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jacopo Mondi X-Patchwork-Id: 11900615 X-Patchwork-Delegate: kieran@bingham.xyz Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 192AF697 for ; Thu, 12 Nov 2020 16:27:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 006CE2100A for ; Thu, 12 Nov 2020 16:27:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727739AbgKLQ1w (ORCPT ); Thu, 12 Nov 2020 11:27:52 -0500 Received: from relay11.mail.gandi.net ([217.70.178.231]:46259 "EHLO relay11.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727646AbgKLQ1w (ORCPT ); Thu, 12 Nov 2020 11:27:52 -0500 Received: from uno.lan (93-34-118-233.ip49.fastwebnet.it [93.34.118.233]) (Authenticated sender: jacopo@jmondi.org) by relay11.mail.gandi.net (Postfix) with ESMTPSA id 94C5A100013; Thu, 12 Nov 2020 16:27:48 +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 Subject: [PATCH v4 2/8] dt-bindings: media: max9286: Document 'maxim,,initial-reverse-channel-mV" Date: Thu, 12 Nov 2020 17:27:23 +0100 Message-Id: <20201112162729.101384-3-jacopo+renesas@jmondi.org> X-Mailer: git-send-email 2.29.1 In-Reply-To: <20201112162729.101384-1-jacopo+renesas@jmondi.org> References: <20201112162729.101384-1-jacopo+renesas@jmondi.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@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 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. Signed-off-by: Jacopo Mondi Reviewed-by: Kieran Bingham --- .../bindings/media/i2c/maxim,max9286.yaml | 23 +++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml b/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml index 9ea827092fdd..c506a0261325 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 (in 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>;