From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B034EC54EE9 for ; Mon, 19 Sep 2022 10:59:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230071AbiISK7L (ORCPT ); Mon, 19 Sep 2022 06:59:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56732 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230063AbiISK63 (ORCPT ); Mon, 19 Sep 2022 06:58:29 -0400 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CAEF02A410; Mon, 19 Sep 2022 03:55:43 -0700 (PDT) Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id C83CE9BA; Mon, 19 Sep 2022 12:55:41 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1663584942; bh=+7fSKzrL50JXSna7WNufX+/+e8+zsZJyumoEjC09AIE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hWlqCXO1lMgKlYKE4GYc/x12J/+Nl8KIeUzK0Y8kJ0g7L+XxbZjLQcO9TKKnV1dPe Ipe0qi2RyUSG/rPXWJcWvjTNt+4BTysYwhB1NRTfVP2zthJ5RgRN7f3Wnm23b//PVN dpqtrlrLTpCLCzXYBvgtmZ6OLeJb4umcWVmykinA= Date: Mon, 19 Sep 2022 13:55:28 +0300 From: Laurent Pinchart To: Sakari Ailus Cc: Marco Felsch , mchehab@kernel.org, robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, kishon@ti.com, vkoul@kernel.org, hverkuil@xs4all.nl, jacopo@jmondi.org, kieran.bingham+renesas@ideasonboard.com, linux-media@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-phy@lists.infradead.org, kernel@pengutronix.de Subject: Re: [PATCH v2 3/4] media: dt-bindings: add bindings for Toshiba TC358746 Message-ID: References: <20220916134535.128131-1-m.felsch@pengutronix.de> <20220916134535.128131-4-m.felsch@pengutronix.de> <20220919100844.bb7tzbql2vpk76xz@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 19, 2022 at 10:23:55AM +0000, Sakari Ailus wrote: > On Mon, Sep 19, 2022 at 12:08:44PM +0200, Marco Felsch wrote: > > On 22-09-18, Laurent Pinchart wrote: > > > On Fri, Sep 16, 2022 at 03:45:34PM +0200, Marco Felsch wrote: > > > > Add the bindings for the Toshiba TC358746 Parallel <-> MIPI-CSI bridge > > > > driver. > > > > > > > > Signed-off-by: Marco Felsch > > > > Reviewed-by: Rob Herring > > > > --- > > > > Changelog: > > > > > > > > v2: > > > > - addded Robs r-b > > > > - s/than/then/ > > > > - added hsync/vsync/bus-type, make hsync/vsync required > > > > - fix example indent > > > > > > > > .../bindings/media/i2c/toshiba,tc358746.yaml | 179 ++++++++++++++++++ > > > > 1 file changed, 179 insertions(+) > > > > create mode 100644 Documentation/devicetree/bindings/media/i2c/toshiba,tc358746.yaml > > > > > > > > diff --git a/Documentation/devicetree/bindings/media/i2c/toshiba,tc358746.yaml b/Documentation/devicetree/bindings/media/i2c/toshiba,tc358746.yaml > > > > new file mode 100644 > > > > index 000000000000..1fa574400bc2 > > > > --- /dev/null > > > > +++ b/Documentation/devicetree/bindings/media/i2c/toshiba,tc358746.yaml > > > > @@ -0,0 +1,179 @@ > > > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > > > > +%YAML 1.2 > > > > +--- > > > > +$id: http://devicetree.org/schemas/media/i2c/toshiba,tc358746.yaml# > > > > +$schema: http://devicetree.org/meta-schemas/core.yaml# > > > > + > > > > +title: Toshiba TC358746 Parallel to MIPI CSI2 Bridge > > > > + > > > > +maintainers: > > > > + - Marco Felsch > > > > + > > > > +description: |- > > > > + The Toshiba TC358746 converts a parallel video stream into a MIPI CSI-2 > > > > + stream. The direction can be either parallel-in -> csi-out or csi-in -> > > > > + parallel-out The chip is programmable trough I2C and SPI but the SPI > > > > + interface is only supported in parallel-in -> csi-out mode. > > > > + > > > > + Note that the current device tree bindings only support the > > > > + parallel-in -> csi-out path. > > > > + > > > > +properties: > > > > + compatible: > > > > + const: toshiba,tc358746 > > > > + > > > > + reg: > > > > + maxItems: 1 > > > > + > > > > + clocks: > > > > + description: > > > > + The phandle to the reference clock source. This corresponds to the > > > > + hardware pin REFCLK. > > > > + maxItems: 1 > > > > + > > > > + clock-names: > > > > + const: refclk > > > > + > > > > +# The bridge can act as clock provider for the sensor. To enable this support > > > > +# #clock-cells must be specified. Attention if this feature is used then the > > > > +# mclk rate must be at least: (2 * link-frequency) / 8 > > > > +# `------------------ยด ^ > > > > +# internal PLL rate smallest possible mclk-div > > > > + "#clock-cells": > > > > + const: 0 > > > > + > > > > + clock-output-names: > > > > + description: > > > > + The clock name of the MCLK output, the default name is tc358746-mclk. > > > > + maxItems: 1 > > > > + > > > > + vddc-supply: > > > > + description: Digital core voltage supply, 1.2 volts > > > > + > > > > + vddio-supply: > > > > + description: Digital I/O voltage supply, 1.8 volts > > > > + > > > > + vddmipi-supply: > > > > + description: MIPI CSI phy voltage supply, 1.2 volts > > > > + > > > > + reset-gpios: > > > > + description: > > > > + The phandle and specifier for the GPIO that controls the chip reset. > > > > + This corresponds to the hardware pin RESX which is physically active low. > > > > + maxItems: 1 > > > > + > > > > + ports: > > > > + $ref: /schemas/graph.yaml#/properties/ports > > > > + properties: > > > > + port@0: > > > > + $ref: /schemas/graph.yaml#/$defs/port-base > > > > + description: Input port > > > > + > > > > + properties: > > > > + endpoint: > > > > + $ref: /schemas/media/video-interfaces.yaml# > > > > + unevaluatedProperties: false > > > > + > > > > + properties: > > > > + hsync-active: > > > > + enum: > > > > + - 0 # Hvalid active high > > > > + vsync-active: > > > > + enum: > > > > + - 0 # Vvalid active high > > > > + bus-type: > > > > + enum: > > > > + - 5 # Parallel > > > > + > > > > + required: > > > > + - hsync-active > > > > + - vsync-active > > > > > > Let's make bus-type required too, to prepare for BT.656 support. > > > > I would have done it when the BT.656 support is added. Since the BT.656 > > don't require the sync signals I would have made a descision: > > - either: hsync/vsync present -> parallel with external syncs, or > > - bus-type present -> parallel bus with embedded syncs. > > > > So we don't bother the system-integrator with specifying unnecessary > > properties. Also having v/hsync required in place with the bus-type (set > > to bt.656) can cause confusion about the final used mode. > > The V4L2 fwnode framework can guess the type of the bus but it's not > recommended to use the feature. Explicit bus types in DT indeed makes it easier for drivers, so if a device can support multiple bus types (even if not implemented yet in the corresponding drivers), the property should be there. > Why do you have hsync-active and vsync-active if both are always zero? Can > the hardware not support other configuration? -- Regards, Laurent Pinchart