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From:   Jacopo Mondi <jacopo+renesas@jmondi.org>
To:     kieran.bingham+renesas@ideasonboard.com,
        laurent.pinchart+renesas@ideasonboard.com,
        niklas.soderlund+renesas@ragnatech.se
Cc:     Jacopo Mondi <jacopo+renesas@jmondi.org>,
        linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
        linux-kernel@vger.kernel.org, Hyun Kwon <hyunk@xilinx.com>,
        Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Subject: [PATCH v3 2/7] dt-bindings: media: max9286: Document 'maxim,high-threshold'
Date:   Fri, 16 Oct 2020 14:06:20 +0200
Message-Id: <20201016120625.64337-3-jacopo+renesas@jmondi.org>
In-Reply-To: <20201016120625.64337-1-jacopo+renesas@jmondi.org>
References: <20201016120625.64337-1-jacopo+renesas@jmondi.org>
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Document the 'maxim,high-threshold' vendor property in the bindings
document of the max9286 driver.

The newly introduced boolean property allows controlling 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 <jacopo+renesas@jmondi.org>
---
 .../bindings/media/i2c/maxim,max9286.yaml         | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml b/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml
index 9ea827092fdd..50e08a7d3204 100644
--- a/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml
+++ b/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml
@@ -51,6 +51,19 @@ properties:
   '#gpio-cells':
     const: 2
 
+  maxim,high-threshold:
+    description: |
+      A boolean property to increase the initial amplitude of the reverse
+      control channel to compensate for remote serializers pre-programmed with
+      high threshold noise-immunity.
+
+      Some camera modules (in example the RDACM20 one) include an on-board MCU
+      that pre-programs the embedded serializer with reverse channel power
+      supply noise immunity enabled. The deserializer shall increase its
+      reverse channel amplitude to compensate that and be able to communicate
+      with the remote end.
+    type: boolean
+
   ports:
     type: object
     description: |
@@ -243,6 +256,8 @@ examples:
         gpio-controller;
         #gpio-cells = <2>;
 
+        maxim,high-threshold;
+
         ports {
           #address-cells = <1>;
           #size-cells = <0>;
-- 
2.28.0